scsi: virtio_scsi: Remove duplicate check if queue is broken

virtqueue_enable_cb() will call virtqueue_poll() which will check if queue
is broken at beginning, so remove the virtqueue_is_broken() call

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Link: https://lore.kernel.org/r/20240116045836.12475-1-lirongqing@baidu.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Add mq_poll support

This adds polling support to virtio-scsi. It's based on and works similar
to virtblk support where we add a module param to specify the number of
poll queues then subtract to calculate the IO queues.

When using 8 poll queues and a vhost worker per queue we see 4K IOPs
with fio:

fio --filename=/dev/sda --direct=1 --rw=randread --bs=4k \
--ioengine=io_uring --hipri --iodepth=128 --numjobs=$NUM_JOBS

increase like:

jobs base poll
1 207K 296K
2 392K 552K
3 581K 860K
4 765K 1235K
5 936K 1598K
6 1104K 1880K
7 1253K 2095K
8 1311k 2187K

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20231214052649.57743-1-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

scsi: core: Improve type safety of scsi_rescan_device()

Most callers of scsi_rescan_device() have the scsi_device pointer readily
available. Pass a struct scsi_device pointer to scsi_rescan_device()
instead of a struct device pointer. This change prevents that a pointer to
another struct device would be passed accidentally to scsi_rescan_device().

Remove the scsi_rescan_device() declaration from the scsi_priv.h header
file since it duplicates the declaration in <scsi/scsi_host.h>.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230822153043.4046244-1-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Remove a useless function call

'inq_result' is known to be NULL. There is no point calling kfree().

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/08740635cdb0f8293e57c557b22e048daae50961.1685345683.git.christophe.jaillet@wanadoo.fr
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio-scsi: Declare SCSI host template const

Make it explicit that the SCSI host template is not modified.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230322195515.1267197-75-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: fix handling of kmalloc failure

There is no check about the return value of kmalloc in
virtscsi_rescan_hotunplug. Add the check to avoid use
of null pointer 'inq_result' in case of the failure
of kmalloc.

Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Message-Id: <20230202064124.22277-1-zyytlz.wz@163.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

scsi: virtio_scsi: Convert to scsi_execute_cmd()

scsi_execute_req() is going to be removed. Convert virtio_scsi to
scsi_execute_cmd().

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: core: Change the return type of .eh_timed_out()

Commit 6600593cbd93 ("block: rename BLK_EH_NOT_HANDLED to BLK_EH_DONE")
made it impossible for .eh_timed_out() implementations to call
scsi_done() without causing a crash.

Restore support for SCSI timeout handlers to call scsi_done() as follows:

* Change all .eh_timed_out() handlers as follows:

- Change the return type into enum scsi_timeout_action.
- Change BLK_EH_RESET_TIMER into SCSI_EH_RESET_TIMER.
- Change BLK_EH_DONE into SCSI_EH_NOT_HANDLED.

* In scsi_timeout(), convert the SCSI_EH_* values into BLK_EH_* values.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221018202958.1902564-3-bvanassche@acm.org
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Drop DID_NEXUS_FAILURE use

DID_NEXUS_FAILURE is internal to the SCSI layer. Drivers must not use it
because:

1. It's not propagated upwards, so SG IO/passthrough users will not see an
error and think a command was successful.

2. There is no handling for it in scsi_decide_disposition() so it results
in entering SCSI error handling.

virtio_scsi gets this when something like qemu returns
VIRTIO_SCSI_S_NEXUS_FAILURE. It looks like qemu returns that error code if
host OS returns DID_NEXUS_FAILURE (qemu's internal
SCSI_HOST_RESERVATION_ERROR maps to DID_NEXUS_FAILURE). This shouldn't
happen for Linux since we don't propagate that error code to userspace.

This has us convert VIRTIO_SCSI_S_NEXUS_FAILURE to a
SAM_STAT_RESERVATION_CONFLICT in case some other virt layer is returning
it. In that case we will still get the reservation confict failure we
expect.

Link: https://lore.kernel.org/r/20220812010027.8251-6-michael.christie@oracle.com
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Drop DID_TARGET_FAILURE use

DID_TARGET_FAILURE is internal to the SCSI layer. Drivers must not use it
because:

1. It's not propagated upwards, so SG IO/passthrough users will not see an
error and think a command was successful.

2. There is no handling for it in scsi_decide_disposition() so it results
in entering SCSI error handling.

virtio_scsi gets this when something like qemu returns
VIRTIO_SCSI_S_TARGET_FAILURE. It looks like qemu returns that error code
if a host OS returns it, but this shouldn't happen for Linux since we never
propagate that error to userspace.

This has us use DID_BAD_TARGET in case some other virt layer is returning
it. In that case we will still get a hard error like before and it conveys
something unexpected happened.

Link: https://lore.kernel.org/r/20220812010027.8251-5-michael.christie@oracle.com
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

block: Change the return type of blk_mq_map_queues() into void

Since blk_mq_map_queues() and the .map_queues() callbacks always return 0,
change their return type into void. Most callers ignore the returned value
anyway.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.garry@huawei.com>
Acked-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Link: https://lore.kernel.org/r/20220815170043.19489-3-bvanassche@acm.org
[axboe: fold in fix from Bart]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

scsi: virtio-scsi: Eliminate anonymous module_init & module_exit

Eliminate anonymous module_init() and module_exit(), which can lead to
confusion or ambiguity when reading System.map, crashes/oops/bugs, or an
initcall_debug log.

Give each of these init and exit functions unique driver-specific names to
eliminate the anonymous names.

Example 1: (System.map)
ffffffff832fc78c t init
ffffffff832fc79e t init
ffffffff832fc8f8 t init

Example 2: (initcall_debug log)
calling init+0x0/0x12 @ 1
initcall init+0x0/0x12 returned 0 after 15 usecs
calling init+0x0/0x60 @ 1
initcall init+0x0/0x60 returned 0 after 2 usecs
calling init+0x0/0x9a @ 1
initcall init+0x0/0x9a returned 0 after 74 usecs

Link: https://lore.kernel.org/r/20220316192010.19001-6-rdunlap@infradead.org
Fixes: 4fe74b1cb051 ("[SCSI] virtio-scsi: SCSI driver for QEMU based virtual machines")
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

virtio: wrap config->reset calls

This will enable cleanups down the road.
The idea is to disable cbs, then add "flush_queued_cbs" callback
as a parameter, this way drivers can flush any work
queued after callbacks have been disabled.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20211013105226.20225-1-mst@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

block: remove the ->rq_disk field in struct request

Just use the disk attached to the request_queue instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Revert "virtio-scsi: don't let virtio core to validate used buffer length"

This reverts commit c57911ebfbfe745cb95da2bcf547c5bae000590f.

Attempts to validate length in the core did not work out. We'll drop
them for now, so revert the dependent changes in drivers.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

scsi: virtio_scsi: Call scsi_done() directly

Conditional statements are faster than indirect calls. Hence call
scsi_done() directly. Additionally, update a comment that refers to the
REQ_ATOM_COMPLETE flag since that flag has been removed a long time ago.

Link: https://lore.kernel.org/r/20211007204618.2196847-2-bvanassche@acm.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

virtio-scsi: don't let virtio core to validate used buffer length

We never tries to use used length, so the patch prevents the virtio
core from validating used length.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20211027022107.14357-5-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

block: move integrity handling out of <linux/blkdev.h>

Split the integrity/metadata handling definitions out into a new header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

scsi: virtio_scsi: Fix spelling mistake "Unsupport" -> "Unsupported"

There are a couple of spelling mistakes in pr_info and pr_err messages.
Fix them.

Link: https://lore.kernel.org/r/20210924230330.143785-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request

Prepare for removal of the request pointer by using scsi_cmd_to_rq()
instead. This patch does not change any functionality.

Link: https://lore.kernel.org/r/20210809230355.8186-49-bvanassche@acm.org
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Add validation for residual bytes from response

This ensures that the residual bytes in response (might come from an
untrusted device) will not exceed the data buffer length.

Link: https://lore.kernel.org/r/20210615105218.214-1-xieyongji@bytedance.com
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Do not overwrite SCSI status

When a sense code is present we should not override the SAM status; the
driver already sets it based on the response from the hypervisor.

In addition we should only copy the sense buffer if one is actually
provided by the hypervisor.

Link: https://lore.kernel.org/r/20210622091153.29231-1-hare@suse.de
Fixes: 464a00c9e0ad ("scsi: core: Kill DRIVER_SENSE")
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: core: Kill DRIVER_SENSE

Replace the check for DRIVER_SENSE with a check for
scsi_status_is_check_condition().

Audit all callsites to ensure the SAM status is set correctly. For
backwards compability move the DRIVER_SENSE definition to sg.h, and update
sg, bsg, and scsi_ioctl to set the DRIVER_SENSE driver_status whenever
SAM_STAT_CHECK_CONDITION is present.

[mkp: fix zeroday srp warning]

Link: https://lore.kernel.org/r/20210427083046.31620-10-hare@suse.de
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

fix

scsi: core: Stop using DRIVER_ERROR

Return the actual error code in __scsi_execute() (which, according to the
documentation, should have happened anyway). And audit all callers to cope
with negative return values from __scsi_execute() and friends.

[mkp: resolve conflict and return bool]

Link: https://lore.kernel.org/r/20210427083046.31620-7-hare@suse.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Rescan the entire target on transport reset when LUN is 0

VirtIO 1.0 spec says:

The removed and rescan events ... when sent for LUN 0, they MAY
apply to the entire target so the driver can ask the initiator
to rescan the target to detect this.

This change introduces the behaviour described above by scanning the entire
SCSI target when LUN is set to 0. This is both a functional and a
performance fix. It aligns the driver with the spec and allows control
planes to hotplug targets with large numbers of LUNs without having to
request a RESCAN for each one of them.

Link: https://lore.kernel.org/r/CY4PR02MB33354370E0A81E75DD9DFE74FB520@CY4PR02MB3335.namprd02.prod.outlook.com
Suggested-by: Felipe Franciosi <felipe@nutanix.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Matej Genci <matej.genci@nutanix.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

virtio_scsi: correct tags for config space fields

Tag config space fields as having virtio endian-ness.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

scsi: virtio-scsi: Correctly handle the case where all LUNs are unplugged

Commit 5ff843721467 ("scsi: virtio_scsi: unplug LUNs when events missed")
missed a corner case in which all the LUNs are unplugged at the same time.

In this case INQUIRY returns DID_BAD_TARGET. Detect this and unplug the
LUN.

Link: https://lore.kernel.org/r/20200729194806.4933-2-mlevitsk@redhat.com
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Demote seemingly unintentional kerneldoc header

This is the only use of kerneldoc in the sourcefile and no descriptions are
provided.

Fixes the following W=1 kernel build warning(s):

drivers/scsi/virtio_scsi.c:109: warning: Function parameter or member 'vscsi' not described in 'virtscsi_complete_cmd'
drivers/scsi/virtio_scsi.c:109: warning: Function parameter or member 'buf' not described in 'virtscsi_complete_cmd'

Link: https://lore.kernel.org/r/20200713080001.128044-13-lee.jones@linaro.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Remove unnecessary condition check

kmem_cache_destroy() and mempool_destroy() both correctly handle null
pointer parameters. There is no need to check if the parameter is null
before calling these functions.

Link: https://lore.kernel.org/r/1594307167-8807-1-git-send-email-xianting_tian@126.com
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Xianting Tian <xianting_tian@126.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: core: remove .for_blk_mq

Not in use anymore. Remove the flag.

Cc: Sathya Prakash <sathya.prakash@broadcom.com>
Cc: Chaitra P B <chaitra.basappa@broadcom.com>
Cc: Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Cc: Ewan D. Milne <emilne@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Link: https://lore.kernel.org/r/20200119071432.18558-3-ming.lei@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: unplug LUNs when events missed

The event handler calls scsi_scan_host() when events are missed, which will
hotplug new LUNs. However, this function won't remove any unplugged LUNs.
The result is that hotunplug doesn't work properly when the number of
unplugged LUNs exceeds the event queue size (currently 8).

Scan existing LUNs when events are missed to check if they are still
present. If not, remove them.

Link: https://lore.kernel.org/r/20190905181903.29756-1-mlupfer@ddn.com
Signed-off-by: Matt Lupfer <mlupfer@ddn.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: implement request batching

Adding the command and kicking the virtqueue so far was done one after
another. Make the kick optional, so that we can take into account
SCMD_LAST. We also need a commit_rqs callback to kick the device if
blk-mq aborts the submission before the last request is reached.

Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Use struct_size() helper

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct virtio_scsi {
...
struct virtio_scsi_vq req_vqs[];
};

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues

with:

struct_size(vscsi, req_vqs, num_queues)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

scsi: virtio_scsi: remove unused 'affinity_hint_set'

The 'affinity_hint_set' is not used any longer since commit
0d9f0a52c8b9 ("virtio_scsi: use virtio IRQ affinity").

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 78

Based on 1 normalized pattern(s):

this work is licensed under the terms of the gnu gpl version 2 or
later see the copying file in the top level directory

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 6 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520075210.858783702@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scsi: virtio_scsi: limit number of hw queues by nr_cpu_ids

When tag_set->nr_maps is 1, the block layer limits the number of hw queues
by nr_cpu_ids. No matter how many hw queues are used by virtio-scsi, as it
has (tag_set->nr_maps == 1), it can use at most nr_cpu_ids hw queues.

In addition, specifically for pci scenario, when the 'num_queues' specified
by qemu is more than maxcpus, virtio-scsi would not be able to allocate
more than maxcpus vectors in order to have a vector for each queue. As a
result, it falls back into MSI-X with one vector for config and one shared
for queues.

Considering above reasons, this patch limits the number of hw queues used
by virtio-scsi by nr_cpu_ids.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

scsi: virtio_scsi: Use HCTX_TYPE_DEFAULT for blk_mq_tag_set->map

Use HCTX_TYPE_DEFAULT instead of 0 to avoid hardcoding.

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: don't send sc payload with tmfs

The virtio scsi spec defines struct virtio_scsi_ctrl_tmf as a set of
device-readable records and a single device-writable response entry:

struct virtio_scsi_ctrl_tmf
{
// Device-readable part
le32 type;
le32 subtype;
u8 lun[8];
le64 id;
// Device-writable part
u8 response;
}

The above should be organised as two descriptor entries (or potentially
more if using VIRTIO_F_ANY_LAYOUT), but without any extra data after "le64
id" or after "u8 response".

The Linux driver doesn't respect that, with virtscsi_abort() and
virtscsi_device_reset() setting cmd->sc before calling virtscsi_tmf(). It
results in the original scsi command payload (or writable buffers) added to
the tmf.

This fixes the problem by leaving cmd->sc zeroed out, which makes
virtscsi_kick_cmd() add the tmf to the control vq without any payload.

Cc: stable@vger.kernel.org
Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: remove bidirectional command support

No real need for bidi support once the OSD code is gone.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: flip the default on use_clustering

Most SCSI drivers want to enable "clustering", that is merging of
segments so that they might span more than a single page. Remove the
ENABLE_CLUSTERING define, and require drivers to explicitly set
DISABLE_CLUSTERING to disable this feature.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Remove per-target data because it is no longer used

Commit b5b6e8c8d3b4 ("scsi: virtio_scsi: fix IO hang caused by automatic
irq vector affinity") removed all virtio_scsi hostdata users. Since the
SCSI host data is no longer used, also remove the host data itself.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

blk-mq: abstract out queue map

This is in preparation for allowing multiple sets of maps per
queue, if so desired.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

scsi: virtio_scsi: fix pi_bytes{out,in} on 4 KiB block size devices

When the underlying device is a 4 KiB logical block size device with a
protection interval exponent of 0, i.e. 4096 bytes data + 8 bytes PI, the
driver miscalculates the pi_bytes{out,in} by a factor of 8x (64 bytes).

This leads to errors on all reads and writes on 4 KiB logical block size
devices when CONFIG_BLK_DEV_INTEGRITY is enabled and the
VIRTIO_SCSI_F_T10_PI feature bit has been negotiated.

Fixes: e6dc783a38ec0 ("virtio-scsi: Enable DIF/DIX modes in SCSI host LLD")
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Edwards <gedwards@ddn.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

treewide: kmalloc() -> kmalloc_array()

The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
patch replaces cases of:

kmalloc(a * b, gfp)

with:
kmalloc_array(a * b, gfp)

as well as handling cases of:

kmalloc(a * b * c, gfp)

with:

kmalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

kmalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

kmalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The tools/ directory was manually excluded, since it has its own
implementation of kmalloc().

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
kmalloc(
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
kmalloc(
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
kmalloc(
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
kmalloc(
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
kmalloc(
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
kmalloc(
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
kmalloc(
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
kmalloc(
- sizeof(__u8) * COUNT
+ COUNT
, ...)
|
kmalloc(
- sizeof(char) * COUNT
+ COUNT
, ...)
|
kmalloc(
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kmalloc
+ kmalloc_array
(
- sizeof(TYPE) * (COUNT_ID)
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(TYPE) * COUNT_ID
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(TYPE) * (COUNT_CONST)
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(TYPE) * COUNT_CONST
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(THING) * (COUNT_ID)
+ COUNT_ID, sizeof(THING)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(THING) * COUNT_ID
+ COUNT_ID, sizeof(THING)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(THING) * (COUNT_CONST)
+ COUNT_CONST, sizeof(THING)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(THING) * COUNT_CONST
+ COUNT_CONST, sizeof(THING)
, ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kmalloc
+ kmalloc_array
(
- SIZE * COUNT
+ COUNT, SIZE
, ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
kmalloc(
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kmalloc(
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kmalloc(
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kmalloc(
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kmalloc(
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kmalloc(
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kmalloc(
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kmalloc(
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
kmalloc(
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kmalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kmalloc(
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kmalloc(
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kmalloc(
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
kmalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
kmalloc(
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kmalloc(
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kmalloc(
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kmalloc(
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kmalloc(
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kmalloc(
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kmalloc(
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kmalloc(
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
kmalloc(C1 * C2 * C3, ...)
|
kmalloc(
- (E1) * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
|
kmalloc(
- (E1) * (E2) * E3
+ array3_size(E1, E2, E3)
, ...)
|
kmalloc(
- (E1) * (E2) * (E3)
+ array3_size(E1, E2, E3)
, ...)
|
kmalloc(
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
kmalloc(sizeof(THING) * C2, ...)
|
kmalloc(sizeof(TYPE) * C2, ...)
|
kmalloc(C1 * C2 * C3, ...)
|
kmalloc(C1 * C2, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(TYPE) * (E2)
+ E2, sizeof(TYPE)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(TYPE) * E2
+ E2, sizeof(TYPE)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(THING) * (E2)
+ E2, sizeof(THING)
, ...)
|
- kmalloc
+ kmalloc_array
(
- sizeof(THING) * E2
+ E2, sizeof(THING)
, ...)
|
- kmalloc
+ kmalloc_array
(
- (E1) * E2
+ E1, E2
, ...)
|
- kmalloc
+ kmalloc_array
(
- (E1) * (E2)
+ E1, E2
, ...)
|
- kmalloc
+ kmalloc_array
(
- E1 * E2
+ E1, E2
, ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>

scsi: virtio_scsi: unify scsi_host_template

Now that virtio_scsi uses blk-mq exclusively, we can remove the
scsi_host_template and associated plumbing for the legacy I/O path.

[mkp: commit desc]

Cc: Omar Sandoval <osandov@fb.com>,
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
Cc: James Bottomley <james.bottomley@hansenpartnership.com>,
Cc: Christoph Hellwig <hch@lst.de>,
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Suggested-by: Christoph Hellwig <hch@lst.de>,
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: fix IO hang caused by automatic irq vector affinity

Since commit 84676c1f21e8ff5 ("genirq/affinity: assign vectors to all
possible CPUs") it is possible to end up in a scenario where only
offline CPUs are mapped to an interrupt vector.

This is only an issue for the legacy I/O path since with blk-mq/scsi-mq
an I/O can't be submitted to a hardware queue if the queue isn't mapped
to an online CPU.

Fix this issue by forcing virtio-scsi to use blk-mq.

[mkp: commit desc]

Cc: Omar Sandoval <osandov@fb.com>,
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
Cc: James Bottomley <james.bottomley@hansenpartnership.com>,
Cc: Christoph Hellwig <hch@lst.de>,
Cc: Don Brace <don.brace@microsemi.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Laurence Oberman <loberman@redhat.com>
Fixes: 84676c1f21e8 ("genirq/affinity: assign vectors to all possible CPUs")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio: virtio_scsi: Set can_queue to the length of the virtqueue.

Since switching to blk-mq as the default in commit 5c279bd9e406
("scsi: default to scsi-mq"), virtio-scsi LUNs consume about 10x as
much kernel memory.

qemu currently allocates a fixed 128 entry virtqueue. can_queue
currently is set to 1024. But with indirect descriptors, each command
in the queue takes 1 virtqueue entry, so the number of commands which
can be queued is equal to the length of the virtqueue.

Note I intend to send a patch to qemu to allow the virtqueue size to be
configured from the qemu command line.

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: always read VPD pages for multiqueue too

Multi-queue virtio-scsi uses a different scsi_host_template struct. Add
the .device_alloc field there, too.

Fixes: 25d1d50e23275e141e3a3fe06c25a99f4c4bf4e0
Cc: stable@vger.kernel.org
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: let host do exception handling

virtio_scsi tries to do exception handling after the default 30 seconds
timeout expires. However, it's better to let the host control the
timeout, otherwise with a heavy I/O load it is likely that an abort will
also timeout. This leads to fatal errors like filesystems going
offline.

Disable the 'sd' timeout and allow the host to do exception handling,
following the precedent of the storvsc driver.

Hannes has a proposal to introduce timeouts in virtio, but this provides
an immediate solution for stable kernels too.

[mkp: fixed typo]

Reported-by: Douglas Miller <dougmill@linux.vnet.ibm.com>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: linux-scsi@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: virtio_scsi: Remove code that zeroes driver-private command data

Since the SCSI core zeroes driver-private command data, remove
that code from the virtio driver.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

virtio: wrap find_vqs

We are going to add more parameters to find_vqs, let's wrap the call so
we don't need to tweak all drivers every time.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

scsi: virtio_scsi: Always try to read VPD pages

Passed through SCSI targets may have transfer limits which come from the
host SCSI controller or something on the host side other than the target
itself.

To make this work properly, the hypervisor can adjust the target's VPD
information to advertise these limits. But for that to work, the guest
has to look at the VPD pages, which we won't do by default if it is an
SPC-2 device, even if it does actually support it.

This adds a workaround to address this, forcing devices attached to a
virtio-scsi controller to always check the VPD pages. This is modelled
on a similar workaround for the storvsc (Hyper-V) SCSI controller,
although that exists for slightly different reasons.

A specific case which causes this is a volume from IBM's IPR RAID
controller (which presents as an SPC-2 device, although it does support
VPD) passed through with qemu's 'scsi-block' device.

[mkp: fixed typo]

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

virtio_scsi: use virtio IRQ affinity

Use automatic IRQ affinity assignment in the virtio layer if available,
and build the blk-mq queues based on it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio: allow drivers to request IRQ affinity when creating VQs

Add a struct irq_affinity pointer to the find_vqs methods, which if set
is used to tell the PCI layer to create the MSI-X vectors for our I/O
virtqueues with the proper affinity from the start. Compared to after
the fact affinity hints this gives us an instantly working setup and
allows to allocate the irq descritors node-local and avoid interconnect
traffic. Last but not least this will allow blk-mq queues are created
based on the interrupt affinity for storage drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

scsi: virtio_scsi: Reject commands when virtqueue is broken

In the case of a graceful set of detaches, where the virtio-scsi-ccw
disk is removed from the guest prior to the controller, the guest
behaves quite normally. Specifically, the detach gets us into
sd_sync_cache to issue a Synchronize Cache(10) command, which
immediately fails (and is retried a couple of times) because the device
has been removed. Later, the removal of the controller sees two CRWs
presented, but there's no further indication of the removal from the
guest viewpoint.

[ 17.217458] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 17.219257] sd 0:0:0:0: [sda] Synchronize Cache(10) failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[ 21.449400] crw_info : CRW reports slct=0, oflw=0, chn=1, rsc=3, anc=0, erc=4, rsid=2
[ 21.449406] crw_info : CRW reports slct=0, oflw=0, chn=0, rsc=3, anc=0, erc=4, rsid=0

However, on s390, the SCSI disks can be removed "by surprise" when an
entire controller (host) is removed and all associated disks are removed
via the loop in scsi_forget_host. The same call to sd_sync_cache is
made, but because the controller has already been removed, the
Synchronize Cache(10) command is neither issued (and then failed) nor
rejected.

That the I/O isn't returned means the guest cannot have other devices
added nor removed, and other tasks (such as shutdown or reboot) issued
by the guest will not complete either. The virtio ring has already been
marked as broken (via virtio_break_device in virtio_ccw_remove), but we
still attempt to queue the command only to have it remain there. The
calling sequence provides a bit of distinction for us:

virtscsi_queuecommand()
-> virtscsi_kick_cmd()
-> virtscsi_add_cmd()
-> virtqueue_add_sgs()
-> virtqueue_add()
if success
return 0
elseif vq->broken or vring_mapping_error()
return -EIO
else
return -ENOSPC

A return of ENOSPC is generally a temporary condition, so returning
"host busy" from virtscsi_queuecommand makes sense here, to have it
redriven in a moment or two. But the EIO return code is more of a
permanent error and so it would be wise to return the I/O itself and
allow the calling thread to finish gracefully. The result is these four
kernel messages in the guest (the fourth one does not occur prior to
this patch):

[ 22.921562] crw_info : CRW reports slct=0, oflw=0, chn=1, rsc=3, anc=0, erc=4, rsid=2
[ 22.921580] crw_info : CRW reports slct=0, oflw=0, chn=0, rsc=3, anc=0, erc=4, rsid=0
[ 22.921978] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 22.921993] sd 0:0:0:0: [sda] Synchronize Cache(10) failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK

I opted to fill in the same response data that is returned from the more
graceful device detach, where the disk device is removed prior to the
controller device.

Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

virtio scsi: Convert to hotplug state machine

Install the callbacks via the state machine. It uses the multi instance
infrastructure of the hotplug code to handle each interface.

virtscsi_set_affinity() is removed from virtscsi_init() because
virtscsi_cpu_notif_add() (the function which registers the instance) is invoked
right after it and the cpuhp_state_add_instance() functions invokes the startup
callback on all online CPUs.

The same thing can not be applied virtscsi_cpu_notif_remove() because
virtscsi_remove_vqs() invokes virtscsi_set_affinity() with affinity = false as
argument but the old CPU_DEAD state invoked the function with affinity = true
(which does not match the DEAD callback).

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: linux-scsi@vger.kernel.org
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: virtualization@lists.linux-foundation.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160906170457.32393-11-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

scsi: virtio_scsi: Use complete() instead complete_all()

There is only one waiter for the completion, therefore there is no need
to use complete_all(). Let's make that clear by using complete() instead
of complete_all().

The usage pattern of the completion is:

waiter context waker context

virtscsi_tmf()
DECLARE_COMPLETION_ONSTACK()
virtscsi_kick_cmd()
wait_for_completion()

virtscsi_complete_free()
complete()

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

virtio scsi: fix unused variable warning

drivers/scsi/virtio_scsi.c: In function 'virtscsi_probe':
drivers/scsi/virtio_scsi.c:952:11: warning: unused variable 'host_prot' [-Wunused-variable]
int err, host_prot;
^

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio_scsi: don't select CONFIG_BLK_DEV_INTEGRITY

T10 PI is just another optional feature, LLDDs should work without
the infrastructure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

virtio/scsi: verify device has config space

Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/scsi needs config space access so make it
fail gracefully if not there.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio: drop VIRTIO_F_VERSION_1 from drivers

Core activates this bit automatically now,
drop it from drivers that set it explicitly.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio_scsi: v1.0 support

Note: for consistency, and to avoid sparse errors,
convert all fields, even those no longer in use
for virtio v1.0.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

scsi: drop reason argument from ->change_queue_depth

Drop the now unused reason argument from the ->change_queue_depth method.
Also add a return value to scsi_adjust_queue_depth, and rename it to
scsi_change_queue_depth now that it can be used as the default
->change_queue_depth implementation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>

scsi: avoid ->change_queue_depth indirection for queue full tracking

All drivers use the implementation for ramping the queue up and down, so
instead of overloading the change_queue_depth method call the
implementation diretly if the driver opts into it by setting the
track_queue_depth flag in the host template.

Note that a few drivers validated the new queue depth in their
change_queue_depth method, but as we never go over the queue depth
set during slave_configure or the sysfs file this isn't nessecary
and can safely be removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Venkatesh Srinivas <venkateshs@google.com>

virtio_scsi: support multi hw queue of blk-mq

Since virtio_scsi has supported multi virtqueue already,
it is natural to map the virtque to hw-queue of blk-mq.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

scsi: don't set tagging state from scsi_adjust_queue_depth

Remove the tagged argument from scsi_adjust_queue_depth, and just let it
handle the queue depth. For most drivers those two are fairly separate,
given that most modern drivers don't care about the SCSI "tagged" status
of a command at all, and many old drivers allow queuing of multiple
untagged commands in the driver.

Instead we start out with the ->simple_tags flag set before calling
->slave_configure, which is how all drivers actually looking at
->simple_tags except for one worke anyway. The one other case looks
broken, but I've kept the behavior as-is for now.

Except for that we only change ->simple_tags from the ->change_queue_type,
and when rejecting a tag message in a single driver, so keeping this
churn out of scsi_adjust_queue_depth is a clear win.

Now that the usage of scsi_adjust_queue_depth is more obvious we can
also remove all the trivial instances in ->slave_alloc or ->slave_configure
that just set it to the cmd_per_lun default.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

virtio_scsi: drop scan callback

Enable VQs early like we do for restore.
This makes it possible to drop the scan callback,
moving scanning into the probe function, and making
code simpler.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio_scsi: fix race on device removal

We cancel event work on device removal, but an interrupt
could trigger immediately after this, and queue it
again.

To fix, set a flag.

Loosely based on patch by Paolo Bonzini

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virito_scsi: use freezable WQ for events

Michael S. Tsirkin noticed a race condition:
we reset device on freeze, but system WQ is still
running so it might try adding bufs to a VQ meanwhile.

To fix, switch to handling events from the freezable WQ.

Reported-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio_scsi: enable VQs early on restore

virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after restore returns, virtio scsi violated
this rule on restore by kicking event vq within restore.

To fix, call virtio_device_ready before using event queue.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio_scsi: move kick event out from virtscsi_init

We currently kick event within virtscsi_init,
before host is fully initialized.

This can in theory confuse guest if device
consumes the buffers immediately.

To fix, move virtscsi_kick_event_all out to scan/restore.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-scsi: Implement change_queue_depth for virtscsi targets

change_queue_depth allows changing per-target queue depth via sysfs.

It also allows the SCSI midlayer to ramp down the number of concurrent
inflight requests in response to a SCSI BUSY status response and allows
the midlayer to ramp the count back up to the device maximum when the
BUSY condition has resolved.

Signed-off-by: Venkatesh Srinivas <venkateshs@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

virtio-scsi: replace target spinlock with seqcount

The spinlock of tgt_lock is only for serializing read and write
req_vq, one lockless seqcount is enough for the purpose.

On one 16core VM with vhost-scsi backend, the patch can improve
IOPS with 3% on random read test.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
[Add initialization in virtscsi_target_alloc. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

virtio-scsi: fix various bad behavior on aborted requests

Even though the virtio-scsi spec guarantees that all requests related
to the TMF will have been completed by the time the TMF itself completes,
the request queue's callback might not have run yet. This causes requests
to be completed more than once, and as a result triggers a variety of
BUGs or oopses.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Venkatesh Srinivas <venkateshs@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@lst.de>

virtio-scsi: avoid cancelling uninitialized work items

Calling the workqueue interface on uninitialized work items isn't a
good idea even if they're zeroed. It's not failing catastrophically only
through happy accidents.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@lst.de>

virtio-scsi: Enable DIF/DIX modes in SCSI host LLD

This patch updates virtscsi_probe() to setup necessary Scsi_Host
level protection resources. (currently hardcoded to 1)

It changes virtscsi_add_cmd() to attach outgoing / incoming
protection SGLs preceeding the data payload, and is using the
new virtio_scsi_cmd_req_pi->pi_bytes[out,in] field to signal
to signal to vhost/scsi bytes to expect for protection data.

(Add missing #include <linux/blkdev.h> for blk_integrity - sfr + nab)

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@dev.mellanox.co.il>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

virtio_scsi: don't call virtqueue_add_sgs(... GFP_NOIO) holding spinlock.

This triggers every time we do a SCSI abort:

virtscsi_tmf -> virtscsi_kick_cmd (grab lock and call) -> virtscsi_add_cmd
-> virtqueue_add_sgs (GFP_NOIO)

Logs look like this:
sd 0:0:0:0: [sda] abort
BUG: sleeping function called from invalid context at mm/slub.c:966
in_atomic(): 1, irqs_disabled(): 1, pid: 6, name: kworker/u2:0
3 locks held by kworker/u2:0/6:
#0: ("scsi_tmf_%d"shost->host_no){......}, at: [<c0153180>] process_one_work+0xe0/0x3d0
#1: ((&(&cmd->abort_work)->work)){......}, at: [<c0153180>] process_one_work+0xe0/0x3d0
#2: (&(&virtscsi_vq->vq_lock)->rlock){......}, at: [<c043f508>] virtscsi_kick_cmd+0x18/0x1b0
CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.15.0-rc5+ #110
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-rc1-0-gb1d4dc9-20140515_140003-nilsson.home.kraxel.org 04/01/2014
Workqueue: scsi_tmf_0 scmd_eh_abort_handler

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

virtio_scsi: use cmd_size

Taken almost entirely from Nicholas Bellinger's scsi-mq conversion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>

virtio_scsi: remove ACCESS_ONCE() and smp_read_barrier_depends()

Access to tgt->req_vq is strictly serialized by spin_lock
of tgt->tgt_lock, so the ACCESS_ONCE() isn't necessary.

smp_read_barrier_depends() in virtscsi_req_done was introduced
to order reading req_vq and decreasing tgt->reqs, but it isn't
needed now because req_vq is read from
scsi->req_vqs[vq->index - VIRTIO_SCSI_VQ_BASE] instead of
tgt->req_vq, so remove the unnecessary barrier.

Also remove related comment about the barrier.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

[SCSI] virtio-scsi: Skip setting affinity on uninitialized vq

virtscsi_init calls virtscsi_remove_vqs on err, even before initializing
the vqs. The latter calls virtscsi_set_affinity, so let's check the
pointer there before setting affinity on it.

This fixes a panic when setting device's num_queues=2 on RHEL 6.5:

qemu-system-x86_64 ... \
-device virtio-scsi-pci,id=scsi0,addr=0x13,...,num_queues=2 \
-drive file=/stor/vm/dummy.raw,id=drive-scsi-disk,... \
-device scsi-hd,drive=drive-scsi-disk,...

[ 0.354734] scsi0 : Virtio SCSI HBA
[ 0.379504] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
[ 0.380141] IP: [<ffffffff814741ef>] __virtscsi_set_affinity+0x4f/0x120
[ 0.380141] PGD 0
[ 0.380141] Oops: 0000 [#1] SMP
[ 0.380141] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0+ #5
[ 0.380141] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007
[ 0.380141] task: ffff88003c9f0000 ti: ffff88003c9f8000 task.ti: ffff88003c9f8000
[ 0.380141] RIP: 0010:[<ffffffff814741ef>] [<ffffffff814741ef>] __virtscsi_set_affinity+0x4f/0x120
[ 0.380141] RSP: 0000:ffff88003c9f9c08 EFLAGS: 00010256
[ 0.380141] RAX: 0000000000000000 RBX: ffff88003c3a9d40 RCX: 0000000000001070
[ 0.380141] RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
[ 0.380141] RBP: ffff88003c9f9c28 R08: 00000000000136c0 R09: ffff88003c801c00
[ 0.380141] R10: ffffffff81475229 R11: 0000000000000008 R12: 0000000000000000
[ 0.380141] R13: ffffffff81cc7ca8 R14: ffff88003cac3d40 R15: ffff88003cac37a0
[ 0.380141] FS: 0000000000000000(0000) GS:ffff88003e400000(0000) knlGS:0000000000000000
[ 0.380141] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 0.380141] CR2: 0000000000000020 CR3: 0000000001c0e000 CR4: 00000000000006f0
[ 0.380141] Stack:
[ 0.380141] ffff88003c3a9d40 0000000000000000 ffff88003cac3d80 ffff88003cac3d40
[ 0.380141] ffff88003c9f9c48 ffffffff814742e8 ffff88003c26d000 ffff88003c26d000
[ 0.380141] ffff88003c9f9c68 ffffffff81474321 ffff88003c26d000 ffff88003c3a9d40
[ 0.380141] Call Trace:
[ 0.380141] [<ffffffff814742e8>] virtscsi_set_affinity+0x28/0x40
[ 0.380141] [<ffffffff81474321>] virtscsi_remove_vqs+0x21/0x50
[ 0.380141] [<ffffffff81475231>] virtscsi_init+0x91/0x240
[ 0.380141] [<ffffffff81365290>] ? vp_get+0x50/0x70
[ 0.380141] [<ffffffff81475544>] virtscsi_probe+0xf4/0x280
[ 0.380141] [<ffffffff81363ea5>] virtio_dev_probe+0xe5/0x140
[ 0.380141] [<ffffffff8144c669>] driver_probe_device+0x89/0x230
[ 0.380141] [<ffffffff8144c8ab>] __driver_attach+0x9b/0xa0
[ 0.380141] [<ffffffff8144c810>] ? driver_probe_device+0x230/0x230
[ 0.380141] [<ffffffff8144c810>] ? driver_probe_device+0x230/0x230
[ 0.380141] [<ffffffff8144ac1c>] bus_for_each_dev+0x8c/0xb0
[ 0.380141] [<ffffffff8144c499>] driver_attach+0x19/0x20
[ 0.380141] [<ffffffff8144bf28>] bus_add_driver+0x198/0x220
[ 0.380141] [<ffffffff8144ce9f>] driver_register+0x5f/0xf0
[ 0.380141] [<ffffffff81d27c91>] ? spi_transport_init+0x79/0x79
[ 0.380141] [<ffffffff8136403b>] register_virtio_driver+0x1b/0x30
[ 0.380141] [<ffffffff81d27d19>] init+0x88/0xd6
[ 0.380141] [<ffffffff81d27c18>] ? scsi_init_procfs+0x5b/0x5b
[ 0.380141] [<ffffffff81ce88a7>] do_one_initcall+0x7f/0x10a
[ 0.380141] [<ffffffff81ce8aa7>] kernel_init_freeable+0x14a/0x1de
[ 0.380141] [<ffffffff81ce8b3b>] ? kernel_init_freeable+0x1de/0x1de
[ 0.380141] [<ffffffff817dec20>] ? rest_init+0x80/0x80
[ 0.380141] [<ffffffff817dec29>] kernel_init+0x9/0xf0
[ 0.380141] [<ffffffff817e68fc>] ret_from_fork+0x7c/0xb0
[ 0.380141] [<ffffffff817dec20>] ? rest_init+0x80/0x80
[ 0.380141] RIP [<ffffffff814741ef>] __virtscsi_set_affinity+0x4f/0x120
[ 0.380141] RSP <ffff88003c9f9c08>
[ 0.380141] CR2: 0000000000000020
[ 0.380141] ---[ end trace 8074b70c3d5e1d73 ]---
[ 0.475018] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
[ 0.475018]
[ 0.475068] Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffff9fffffff)
[ 0.475068] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009

[jejb: checkpatch fixes]
Signed-off-by: Fam Zheng <famz@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

virtio-scsi: Fix hotcpu_notifier use-after-free with virtscsi_freeze

vqs are freed in virtscsi_freeze but the hotcpu_notifier is not
unregistered. We will have a use-after-free usage when the notifier
callback is called after virtscsi_freeze.

Fixes: 285e71ea6f3583a85e27cb2b9a7d8c35d4c0d558
("virtio-scsi: reset virtqueue affinity when doing cpu hotplug")

Cc: stable@vger.kernel.org
Signed-off-by: Asias He <asias.hejun@gmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio_scsi: verify if queue is broken after virtqueue_get_buf()

If virtqueue_get_buf() returned with a NULL pointer avoid a possibly
endless loop by checking for a broken virtqueue.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio: use size-based config accessors.

This lets the transport do endian conversion if necessary, and insulates
the drivers from the difference.

Most drivers can use the simple helpers virtio_cread() and virtio_cwrite().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio: pm: use CONFIG_PM_SLEEP instead of CONFIG_PM

The freeze and restore functions defined in virtio drivers are used
for suspend and hibernate, so CONFIG_PM_SLEEP is more appropriate than
CONFIG_PM. This patch replace all CONFIG_PM with CONFIG_PM_SLEEP for
virtio drivers that implement freeze and restore callbacks.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-scsi: Fix virtqueue affinity setup

vscsi->num_queues counts the number of request virtqueue which does not
include the control and event virtqueue. It is wrong to subtract
VIRTIO_SCSI_VQ_BASE from vscsi->num_queues.

This patch fixes the following panic.

(qemu) device_del scsi0

BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
PGD 0
Oops: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 659 Comm: kworker/0:1 Not tainted 3.11.0-rc2+ #1172
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: kacpi_hotplug _handle_hotplug_event_func
task: ffff88007bee1cc0 ti: ffff88007bfe4000 task.ti: ffff88007bfe4000
RIP: 0010:[<ffffffff8179b29f>] [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
RSP: 0018:ffff88007bfe5a38 EFLAGS: 00010202
RAX: 0000000000000010 RBX: ffff880077fd0d28 RCX: 0000000000000050
RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000000
RBP: ffff88007bfe5a58 R08: ffff880077f6ff00 R09: 0000000000000001
R10: ffffffff8143e673 R11: 0000000000000001 R12: 0000000000000001
R13: ffff880077fd0800 R14: 0000000000000000 R15: ffff88007bf489b0
FS: 0000000000000000(0000) GS:ffff88007ea00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000020 CR3: 0000000079f8b000 CR4: 00000000000006f0
Stack:
ffff880077fd0d28 0000000000000000 ffff880077fd0800 0000000000000008
ffff88007bfe5a78 ffffffff8179b37d ffff88007bccc800 ffff88007bccc800
ffff88007bfe5a98 ffffffff8179b3b6 ffff88007bccc800 ffff880077fd0d28
Call Trace:
[<ffffffff8179b37d>] virtscsi_set_affinity+0x2d/0x40
[<ffffffff8179b3b6>] virtscsi_remove_vqs+0x26/0x50
[<ffffffff8179c7d2>] virtscsi_remove+0x82/0xa0
[<ffffffff814cb6b2>] virtio_dev_remove+0x22/0x70
[<ffffffff8167ca49>] __device_release_driver+0x69/0xd0
[<ffffffff8167cb9d>] device_release_driver+0x2d/0x40
[<ffffffff8167bb96>] bus_remove_device+0x116/0x150
[<ffffffff81679936>] device_del+0x126/0x1e0
[<ffffffff81679a06>] device_unregister+0x16/0x30
[<ffffffff814cb889>] unregister_virtio_device+0x19/0x30
[<ffffffff814cdad6>] virtio_pci_remove+0x36/0x80
[<ffffffff81464ae7>] pci_device_remove+0x37/0x70
[<ffffffff8167ca49>] __device_release_driver+0x69/0xd0
[<ffffffff8167cb9d>] device_release_driver+0x2d/0x40
[<ffffffff8167bb96>] bus_remove_device+0x116/0x150
[<ffffffff81679936>] device_del+0x126/0x1e0
[<ffffffff8145edfc>] pci_stop_bus_device+0x9c/0xb0
[<ffffffff8145f036>] pci_stop_and_remove_bus_device+0x16/0x30
[<ffffffff81474a9e>] acpiphp_disable_slot+0x8e/0x150
[<ffffffff81474f6a>] hotplug_event_func+0xba/0x1a0
[<ffffffff814906c8>] ? acpi_os_release_object+0xe/0x12
[<ffffffff81475911>] _handle_hotplug_event_func+0x31/0x70
[<ffffffff810b5333>] process_one_work+0x183/0x500
[<ffffffff810b66e2>] worker_thread+0x122/0x400
[<ffffffff810b65c0>] ? manage_workers+0x2d0/0x2d0
[<ffffffff810bc5de>] kthread+0xce/0xe0
[<ffffffff810bc510>] ? kthread_freezable_should_stop+0x70/0x70
[<ffffffff81ca045c>] ret_from_fork+0x7c/0xb0
[<ffffffff810bc510>] ? kthread_freezable_should_stop+0x70/0x70
Code: 01 00 00 00 74 59 45 31 e4 83 bb c8 01 00 00 02 74 46 66 2e 0f 1f 84 00 00 00 00 00 49 63 c4 48 c1 e0 04 48 8b bc 0
3 10 02 00 00 <48> 8b 47 20 48 8b 80 d0 01 00 00 48 8b 40 50 48 85 c0 74 07 be
RIP [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
RSP <ffff88007bfe5a38>
CR2: 0000000000000020
---[ end trace 99679331a3775f48 ]---

CC: stable@vger.kernel.org
Signed-off-by: Asias He <asias@redhat.com>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-scsi: reset virtqueue affinity when doing cpu hotplug

Add hot cpu notifier to reset the request virtqueue affinity
when doing cpu hotplug.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-scsi: introduce multiqueue support

This patch adds queue steering to virtio-scsi. When a target is sent
multiple requests, we always drive them to the same queue so that FIFO
processing order is kept. However, if a target was idle, we can choose
a queue arbitrarily. In this case the queue is chosen according to the
current VCPU, so the driver expects the number of request queues to be
equal to the number of VCPUs. This makes it easy and fast to select
the queue, and also lets the driver optimize the IRQ affinity for the
virtqueues (each virtqueue's affinity is set to the CPU that "owns"
the queue).

The speedup comes from improving cache locality and giving CPU affinity
to the virtqueues, which is why this scheme was selected. Assuming that
the thread that is sending requests to the device is I/O-bound, it is
likely to be sleeping at the time the ISR is executed, and thus executing
the ISR on the same processor that sent the requests is cheap.

However, the kernel will not execute the ISR on the "best" processor
unless you explicitly set the affinity. This is because in practice
you will have many such I/O-bound processes and thus many otherwise
idle processors. Then the kernel will execute the ISR on a random
processor, rather than the one that is sending requests to the device.

The alternative to per-CPU virtqueues is per-target virtqueues. To
achieve the same locality, we could dynamically choose the virtqueue's
affinity based on the CPU of the last task that sent a request. This
is less appealing because we do not set the affinity directly---we only
provide a hint to the irqbalanced running in userspace. Dynamically
changing the affinity only works if the userspace applies the hint
fast enough.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Asias He <asias@redhat.com>
Tested-by: Venkatesh Srinivas <venkateshs@google.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-scsi: push vq lock/unlock into virtscsi_vq_done

Avoid duplicated code in all of the callers.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-scsi: pass struct virtio_scsi to virtqueue completion function

This will be needed soon in order to retrieve the per-target
struct.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-scsi: redo allocation of target data

virtio_scsi_target_state is now empty. We will find new uses for it in
the next few patches, so this patch does not drop it completely.

And as James suggested, we use entries target_alloc and target_destroy
in the host template to allocate and destroy the virtio_scsi_target_state
of each target, attach this struct to scsi_target->hostdata. Now
we can get at it from the sdev with scsi_target(sdev)->hostdata.
No messing around with fixed size arrays and bulk memory allocation
and no need to pass in the maximum target size as a parameter because
everything should now happen dynamically.

Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio_scsi: use virtqueue_add_inbuf() for virtscsi_kick_event.

It's a bit clearer, and add_buf is going away.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Asias He <asias@redhat.com>

virtio-scsi: use virtqueue_add_sgs for command buffers

Using the new virtqueue_add_sgs function lets us simplify the queueing
path. In particular, all data protected by the tgt_lock is just gone
(multiqueue will find a new use for the lock).

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio-scsi: use pr_err() instead of printk()

Convert the virtio-scsi driver to use pr_err() instead of printk().

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Drivers: scsi: remove __dev* attributes.

CONFIG_HOTPLUG is going away as an option. As a result, the __dev*
markings need to be removed.

This change removes the use of __devinit, __devexit_p, __devinitdata,
__devinitconst, and __devexit from these drivers.

Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.

Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Adam Radford <linuxraid@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0

We simplified virtqueue_add_buf(), make it clear in the callers.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

[SCSI] virtio_scsi: fix memory leak on full queue condition.

virtscsi_queuecommand was leaking memory when the virtio queue was full.

Tested: Guest operates correctly even with very small queue sizes, validated
we're not leaking kmalloc-192 sized allocations anymore.

Signed-off-by: Eric Northup <digitaleric@google.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: support online resizing of disks

Support the LUN parameter change event. Currently, the host fires this event
when the capacity of a disk is changed from the virtual machine monitor.
The resize then appears in the kernel log like this:

sd 0:0:0:0: [sda] 46137344 512-byte logical blocks: (23.6 GB/22.0 GIb)
sda: detected capacity change from 22548578304 to 23622320128

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: fix LUNs greater than 255

virtio-scsi needs to report LUNs greater than 256 using the "flat"
format. Because the Linux SCSI layer just maps the SCSI LUN to
an u32, without any parsing, these end up in the range from 16640
to 32767. Fix max_lun to account for the possibility that logical
unit numbers are encoded with the "flat" format.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: initialize scatterlist structure

The sg struct is used without being initialized, which breaks
when CONFIG_DEBUG_SG is enabled.

Cc: stable@vger.kernel.org
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

When using the commands below to write some data to a virtio-scsi LUN of the
QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash.

# sudo mkfs.ext4 /dev/sdb (/dev/sdb is the virtio-scsi LUN.)
# sudo mount /dev/sdb /mnt
# dd if=/dev/zero of=/mnt/file bs=1M count=1024

In current implementation, sg_set_buf is called to add buffers to sg list which
is put into the virtqueue eventually. But if there are some HighMem pages in
table->sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
return NULL value. This will cause QEMU exit when virtqueue_map_sg is called
in QEMU because an invalid GPA is passed by virtqueue.

Two solutions are discussed here:
http://lkml.indiana.edu/hypermail/linux/kernel/1207.3/00675.html

Finally, value assignment approach was adopted because:

Value assignment creates a well-formed scatterlist, because the termination
marker in source sg_list has been set in blk_rq_map_sg(). The last entry of the
source sg_list is just copied to the the last entry in destination list. Note
that, for now, virtio_ring does not care about the form of the scatterlist and
simply processes the first out_num + in_num consecutive elements of the sg[]
array.

I have tested the patch on my workstation. QEMU would not crash any more.

Cc: <stable@vger.kernel.org> # 3.4: 4fe74b1: [SCSI] virtio-scsi: SCSI driver
Signed-off-by: Wang Sen <senwang@linux.vnet.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: Add vdrv->scan for post VIRTIO_CONFIG_S_DRIVER_OK LUN scanning

This patch changes virtio-scsi to use a new virtio_driver->scan() callback
so that scsi_scan_host() can be properly invoked once virtio_dev_probe() has
set add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK) to signal active virtio-ring
operation, instead of from within virtscsi_probe().

This fixes a bug where SCSI LUN scanning for both virtio-scsi-raw and
virtio-scsi/tcm_vhost setups was happening before VIRTIO_CONFIG_S_DRIVER_OK
had been set, causing VIRTIO_SCSI_S_BAD_TARGET to occur. This fixes a bug
with virtio-scsi/tcm_vhost where LUN scan was not detecting LUNs.

Tested with virtio-scsi-raw + virtio-scsi/tcm_vhost w/ IBLOCK on 3.5-rc2 code.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: hotplug support for virtio-scsi

This patch implements the hotplug support for virtio-scsi.
When there is a device attached/detached, the virtio-scsi driver will be
signaled via event virtual queue and it will add/remove the scsi device
in question automatically.

Signed-off-by: Sen Wang <senwang@linux.vnet.ibm.com>
Signed-off-by: Cong Meng <mc@linux.vnet.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: split scatterlist per target

To improve performance for I/O to different targets, add a separate
scatterlist for each of them.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: release sg_lock after add_buf

We do not need the sglist after calling virtqueue_add_buf. Hence we
can "pipeline" the locked operations and start preparing the sglist
for the next request while we kick the virtqueue.

Together with the previous two patches, this improves performance as
follows. For a simple "if=/dev/sda of=/dev/null bs=128M iflag=direct"
(the source being a 10G disk, residing entirely in the host buffer cache),
the additional locking does not cause any penalty with only one dd
process, but 2 simultaneous I/O operations improve their times by 3%:

number of simultaneous dd
1 2
----------------------------------------
current 5.9958s 10.2640s
patched 5.9531s 9.8663s

(Times are best of 10).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: split locking per vq

Keep a separate lock for each virtqueue. While not particularly
important now, it prepares the code for when we will add support
for multiple request queues. It is also more tidy as soon as
we introduce a separate lock for the sglist.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: unlock during kick

Separate virtqueue_kick_prepare from virtqueue_notify, so that the
expensive vmexit is done without holding the lock.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio_scsi: fix TMF use-after-free

Fix a use-after-free in the TMF path, where cmd may have been already
freed by virtscsi_complete_free when wait_for_completion restarts
executing virtscsi_tmf. Technically a race, but in practice the command
will always be freed long before the completion waiter is awoken.

The fix is to make callers specifying a completion responsible for
freeing the command in all cases.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] virtio-scsi: SCSI driver for QEMU based virtual machines

The virtio-scsi HBA is the basis of an alternative storage stack
for QEMU-based virtual machines (including KVM). Compared to
virtio-blk it is more scalable, because it supports many LUNs
on a single PCI slot), more powerful (it more easily supports
passthrough of host devices to the guest) and more easily
extensible (new SCSI features implemented by QEMU should not
require updating the driver in the guest).

Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>