mtd_blkdevs: pass queue_limits to blk_mq_alloc_disk

Pass the few limits mtd_blkdevs imposes directly to blk_mq_alloc_disk
instead of setting them one at a time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240215070300.2200308-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: pass a queue_limits argument to blk_mq_alloc_disk

Pass a queue_limits to blk_mq_alloc_disk and apply it if non-NULL. This
will allow allocating queues with valid queue limits instead of setting
the values one at a time later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20240213073425.1621680-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: use the default discard granularity

The discard granularity now defaults to a single sector, so don't set
that value explicitly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Richard Weinberger <richard@nod.at>
Link: https://lore.kernel.org/r/20231228075545.362768-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd: Fix gluebi NULL pointer dereference caused by ftl notifier

If both ftl.ko and gluebi.ko are loaded, the notifier of ftl
triggers NULL pointer dereference when trying to access
‘gluebi->desc’ in gluebi_read().

ubi_gluebi_init
ubi_register_volume_notifier
ubi_enumerate_volumes
ubi_notify_all
gluebi_notify nb->notifier_call()
gluebi_create
mtd_device_register
mtd_device_parse_register
add_mtd_device
blktrans_notify_add not->add()
ftl_add_mtd tr->add_mtd()
scan_header
mtd_read
mtd_read_oob
mtd_read_oob_std
gluebi_read mtd->read()
gluebi->desc - NULL

Detailed reproduction information available at the Link [1],

In the normal case, obtain gluebi->desc in the gluebi_get_device(),
and access gluebi->desc in the gluebi_read(). However,
gluebi_get_device() is not executed in advance in the
ftl_add_mtd() process, which leads to NULL pointer dereference.

The solution for the gluebi module is to run jffs2 on the UBI
volume without considering working with ftl or mtdblock [2].
Therefore, this problem can be avoided by preventing gluebi from
creating the mtdblock device after creating mtd partition of the
type MTD_UBIVOLUME.

Fixes: 2ba3d76a1e29 ("UBI: make gluebi a separate module")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217992 [1]
Link: https://lore.kernel.org/lkml/441107100.23734.1697904580252.JavaMail.zimbra@nod.at/ [2]
Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Acked-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20231220024619.2138625-1-wangzhaolong1@huawei.com

block: replace fmode_t with a block-specific type for block open flags

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd: block: use a simple bool to track open for write

Instead of propagating the fmode_t, just use a bool to track if a mtd
block device was opened for writing.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Richard Weinberger <richard@nod.at>
Link: https://lore.kernel.org/r/20230608110258.189493-23-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the unused mode argument to ->release

The mode argument to the ->release block_device_operation is never used,
so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: pass a gendisk to ->open

->open is only called on the whole device. Make that explicit by
passing a gendisk instead of the block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove blk_cleanup_disk

blk_cleanup_disk is nothing but a trivial wrapper for put_disk now,
so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20220619060552.1850436-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove QUEUE_FLAG_DISCARD

Just use a non-zero max_discard_sectors as an indicator for discard
support, similar to what is done for write zeroes.

The only places where needs special attention is the RAID5 driver,
which must clear discard support for security reasons by default,
even if the default stacking rules would allow for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Jan Höppner <hoeppner@linux.ibm.com> [s390]
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-25-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: avoid soft lockups with some mtd/spi devices

With some spi devices, the heavy cpu usage due to polling the spi
registers may lead to netdev timeouts, RCU complaints, etc. This can
be acute in the absence of CONFIG_PREEMPT. This patch allows to give
enough breathing room to avoid those incorrectly detected netdev
timeouts for example.

Example splat on 5.10.92:
[ 828.399306] rcu: INFO: rcu_sched self-detected stall on CPU
...
[ 828.419245] Task dump for CPU 1:
[ 828.422465] task:kworker/1:1H state:R running task on cpu 1 stack: 0 pid: 76 ppid: 2 flags:0x0000002a
[ 828.433132] Workqueue: kblockd blk_mq_run_work_fn
[ 828.437820] Call trace:
...
[ 828.512267] spi_mem_exec_op+0x4d0/0xde0
[ 828.516184] spi_mem_dirmap_read+0x180/0x39c
[ 828.520443] spi_nor_read_data+0x428/0x7e8
[ 828.524523] spi_nor_read+0x154/0x214
[ 828.528172] mtd_read_oob+0x440/0x714
[ 828.531815] mtd_read+0xac/0x120
[ 828.535030] mtdblock_readsect+0x178/0x230
[ 828.539102] mtd_blktrans_work+0x9fc/0xf28
[ 828.543177] mtd_queue_rq+0x1ac/0x2e4
[ 828.546827] blk_mq_dispatch_rq_list+0x2cc/0xa44
[ 828.551419] blk_mq_do_dispatch_sched+0xb0/0x7cc
[ 828.556010] __blk_mq_sched_dispatch_requests+0x350/0x494
[ 828.561372] blk_mq_sched_dispatch_requests+0xac/0xe4
[ 828.566387] __blk_mq_run_hw_queue+0x130/0x254
[ 828.570806] blk_mq_run_work_fn+0x50/0x60
[ 828.574814] process_one_work+0x578/0xf1c
[ 828.578814] worker_thread+0x5dc/0xea0
[ 828.582547] kthread+0x270/0x2d4
[ 828.585765] ret_from_fork+0x10/0x30

Signed-off-by: David Decotigny <ddecotig@google.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220126101120.676021-1-decot+git@google.com

mtd_blkdevs: don't scan partitions for plain mtdblock

mtdblock / mtdblock_ro set part_bits to 0 and thus nevever scanned
partitions. Restore that behavior by setting the GENHD_FL_NO_PART flag.

Fixes: 1ebe2e5f9d68e94c ("block: remove GENHD_FL_EXT_DEVT")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20211206070409.2836165-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: remove the sector out of range check in do_blktrans_request

The block layer already performs this check, no need to duplicate it in
the driver.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove rq_flush_dcache_pages

This function is trivial, and flush_dcache_page is always defined, so
just open code it in the 2.5 callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Revert "mtd_blkdevs: don't scan partitions for plain mtdblock"

This reverts commit 776b54e97a7d993ba23696e032426d5dea5bbe70.

Looks like a last minute edit snuck into this patch, and as a result,
it doesn't even compile. Revert the change for now.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: don't scan partitions for plain mtdblock

mtdblock / mtdblock_ro set part_bits to 0 and thus nevever scanned
partitions. Restore that behavior by setting the GENHD_FL_NO_PART flag.

Fixes: 1ebe2e5f9d68e94c ("block: remove GENHD_FL_EXT_DEVT")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20211206070409.2836165-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd: add add_disk() error handling

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20211015233028.2167651-10-mcgrof@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: simplify the refcounting in blktrans_{open, release}

Always grab a reference to the mtd_blktrans_dev in ->open instead of
just on the first open, and do away with the additional temporary
references in ->open and ->release.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210823073359.705281-9-hch@lst.de

mtd_blkdevs: simplify blktrans_getgeo

No need to grab a mtd_blktrans_dev given that ->open already holds one
and ->getgeo can only be called on an open disk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210823073359.705281-8-hch@lst.de

mtd_blkdevs: remove blktrans_ref_mutex

blktrans_ref_mutex is not actually needed. The kref is serialized
internally, and devnum assignment in add_mtd_blktrans_dev happens before
the disk is added and thus any of the block_device_operations methods
otherwise using it are called. It is also already serialized by the
global mtd_table_mutex.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210823073359.705281-7-hch@lst.de

mtd_blkdevs: simplify blktrans_dev_get

->private_data is set before the disk is added and never cleared, so don't
bother trying to handle a NULL pointer there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210823073359.705281-6-hch@lst.de

mtd_blkdevs: use lockdep_assert_held

Use lockdep_assert_held to ensure mtd_table_mutex is held instead of
mutex_trylock games.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210823073359.705281-3-hch@lst.de

mtd_blkdevs: don't hold del_mtd_blktrans_dev in blktrans_{open, release}

There is nothing that this protects against except for slightly reducing
the window when new opens can appear just before calling del_gendisk.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210823073359.705281-2-hch@lst.de

mtd: fix lock hierarchy in deregister_mtd_blktrans

There is a lock hierarchy of major_names_lock --> mtd_table_mutex. One
existing chain is as follows:

1. major_names_lock --> loop_ctl_mutex (when blk_request_module calls
loop_probe)

2. loop_ctl_mutex --> bdev->bd_mutex (when loop_control_ioctl calls
loop_remove, which then calls del_gendisk)

3. bdev->bd_mutex --> mtd_table_mutex (when blkdev_get_by_dev calls
__blkdev_get, which then calls blktrans_open)

Since unregister_blkdev grabs the major_names_lock, we need to call it
outside the critical section for mtd_table_mutex, otherwise we invert
the lock hierarchy.

Reported-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210717100719.728829-1-desmondcheongzx@gmail.com

mtd: break circular locks in register_mtd_blktrans

Syzbot reported a circular locking dependency:
https://syzkaller.appspot.com/bug?id=7bd106c28e846d1023d4ca915718b1a0905444cb

This happens because of the following lock dependencies:

1. loop_ctl_mutex -> bdev->bd_mutex (when loop_control_ioctl calls
loop_remove, which then calls del_gendisk; this also happens in
loop_exit which eventually calls loop_remove)

2. bdev->bd_mutex -> mtd_table_mutex (when blkdev_get_by_dev calls
__blkdev_get, which then calls blktrans_open)

3. mtd_table_mutex -> major_names_lock (when register_mtd_blktrans
calls __register_blkdev)

4. major_names_lock -> loop_ctl_mutex (when blk_request_module calls
loop_probe)

Hence there's an overall dependency of:

loop_ctl_mutex ----------> bdev->bd_mutex
^ |
| |
| v
major_names_lock <--------- mtd_table_mutex

We can break this circular dependency by holding mtd_table_mutex only
for the required critical section in register_mtd_blktrans. This
avoids the mtd_table_mutex -> major_names_lock dependency.

Reported-and-tested-by: syzbot+6a8a0d93c91e8fbf2e80@syzkaller.appspotmail.com
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210617160904.570111-1-desmondcheongzx@gmail.com

mtd: mtd_blkdevs: Initialize rq.limits.discard_granularity

Since commit b35fd7422c2f8("block: check queue's limits.discard_granularity
in __blkdev_issue_discard()") checks rq.limits.discard_granularity in
__blkdev_issue_discard(), we may get following warnings on formatted ftl:

WARNING: CPU: 2 PID: 7313 at block/blk-lib.c:51
__blkdev_issue_discard+0x2a7/0x390

Reproducer:
1. ftl_format /dev/mtd0
2. modprobe ftl
3. mkfs.vfat /dev/ftla
4. mount -odiscard /dev/ftla temp
5. dd if=/dev/zero of=temp/tst bs=1M count=10 oflag=direct
6. dd if=/dev/zero of=temp/tst bs=1M count=10 oflag=direct

Fix it by initializing rq.limits.discard_granularity if device supports
discard operation.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210615093905.3473709-1-chengzhihao1@huawei.com

mtd_blkdevs: initialze new->rq in add_mtd_blktrans_dev

Various places expect the request_queue in ->rq. Initialize it to
avoid NULL pointer derefences.

Fixes: 6966bb921def ("mtd_blkdevs: use blk_mq_alloc_disk")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: don't override BLKFLSBUF

BLKFLSBUF is not supposed to actually send a flush command to the device,
but to tear down buffer cache structures. Remove the mtd_blkdevs
implementation and just use the default semantics instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 102

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
51 franklin st fifth floor boston ma 02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 50 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
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/20190523091649.499889647@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mtd_blkdevs: convert to blk-mq

Straight forward conversion, using an internal list to enable the
driver to pull requests at will.

Dynamically allocate the tag set to avoid having to pull in the
block headers for blktrans.h, since various mtd drivers use
block conflicting names for defines and functions.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Tested-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: genhd: add 'groups' argument to device_add_disk

Update device_add_disk() to take an 'groups' argument so that
individual drivers can register a device with additional sysfs
attributes.
This avoids race condition the driver would otherwise have if these
groups were to be created with sysfs_add_groups().

Signed-off-by: Martin Wilck <martin.wilck@suse.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: handle highmem pages

Just kmap the single payload page before passing it on to the FTL.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Use blk_queue_flag_*() in drivers instead of queue_flag_*()

This patch has been generated as follows:

for verb in set_unlocked clear_unlocked set clear; do
replace-in-files queue_flag_${verb} blk_queue_flag_${verb%_unlocked} \
$(git grep -lw queue_flag_${verb} drivers block/bsg*)
done

Except for protecting all queue flag changes with the queue lock
this patch does not change any functionality.

Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd: blkdevs: Fix mtd block write failure

All the MTD block write requests are failing with
following error messages

mkfs.ext4 /dev/mtdblock0

print_req_error: I/O error, dev mtdblock0, sector 0
Buffer I/O error on dev mtdblock0, logical block 0,
lost async page write

The control is going to default case after block write request
because of missing return.

Fixes: commit 2a842acab109 ("block: introduce new block status code type")
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

block: don't set bounce limit in blk_init_queue

Instead move it to the callers. Those that either don't use bio_data() or
page_address() or are specific to architectures that do not support highmem
are skipped.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: introduce new block status code type

Currently we use nornal Linux errno values in the block layer, and while
we accept any error a few have overloaded magic meanings. This patch
instead introduces a new blk_status_t value that holds block layer specific
status codes and explicitly explains their meaning. Helpers to convert from
and to the previous special meanings are provided for now, but I suspect
we want to get rid of them in the long run - those drivers that have a
errno input (e.g. networking) usually get errnos that don't know about
the special block layer overloads, and similarly returning them to userspace
will usually return somethings that strictly speaking isn't correct
for file system operations, but that's left as an exercise for later.

For now the set of errors is a very limited set that closely corresponds
to the previous overloaded errno values, but there is some low hanging
fruite to improve it.

blk_status_t (ab)uses the sparse __bitwise annotations to allow for sparse
typechecking, so that we can easily catch places passing the wrong values.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: fold cmd_type into the REQ_OP_ space

Instead of keeping two levels of indirection for requests types, fold it
all into the operations. The little caveat here is that previously
cmd_type only applied to struct request, while the request and bio op
fields were set to plain REQ_OP_READ/WRITE even for passthrough
operations.

Instead this patch adds new REQ_OP_* for SCSI passthrough and driver
private requests, althought it has to add two for each so that we
can communicate the data in/out nature of the request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

block: convert to device_add_disk()

For block drivers that specify a parent device, convert them to use
device_add_disk().

This conversion was done with the following semantic patch:

@@
struct gendisk *disk;
expression E;
@@

- disk->driverfs_dev = E;
...
- add_disk(disk);
+ device_add_disk(E, disk);

@@
struct gendisk *disk;
expression E1, E2;
@@

- disk->driverfs_dev = E1;
...
E2 = disk;
...
- add_disk(E2);
+ device_add_disk(E1, E2);

...plus some manual fixups for a few missed conversions.

Cc: Jens Axboe <axboe@fb.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

block, drivers: add REQ_OP_FLUSH operation

This adds a REQ_OP_FLUSH operation that is sent to request_fn
based drivers by the block layer's flush code, instead of
sending requests with the request->cmd_flags REQ_FLUSH bit set.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers: use req op accessor

The req operation REQ_OP is separated from the rq_flag_bits
definition. This converts the block layer drivers to
use req_op to get the op from the request struct.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

mtd: switch to using blk_queue_write_cache()

Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

mtd: blkdevs: fix potential deadlock + lockdep warnings

Commit 073db4a51ee4 ("mtd: fix: avoid race condition when accessing
mtd->usecount") fixed a race condition but due to poor ordering of the
mutex acquisition, introduced a potential deadlock.

The deadlock can occur, for example, when rmmod'ing the m25p80 module, which
will delete one or more MTDs, along with any corresponding mtdblock
devices. This could potentially race with an acquisition of the block
device as follows.

-> blktrans_open()
-> mutex_lock(&dev->lock);
-> mutex_lock(&mtd_table_mutex);

-> del_mtd_device()
-> mutex_lock(&mtd_table_mutex);
-> blktrans_notify_remove() -> del_mtd_blktrans_dev()
-> mutex_lock(&dev->lock);

This is a classic (potential) ABBA deadlock, which can be fixed by
making the A->B ordering consistent everywhere. There was no real
purpose to the ordering in the original patch, AFAIR, so this shouldn't
be a problem. This ordering was actually already present in
del_mtd_blktrans_dev(), for one, where the function tried to ensure that
its caller already held mtd_table_mutex before it acquired &dev->lock:

if (mutex_trylock(&mtd_table_mutex)) {
mutex_unlock(&mtd_table_mutex);
BUG();
}

So, reverse the ordering of acquisition of &dev->lock and &mtd_table_mutex so
we always acquire mtd_table_mutex first.

Snippets of the lockdep output follow:

# modprobe -r m25p80
[ 53.419251]
[ 53.420838] ======================================================
[ 53.427300] [ INFO: possible circular locking dependency detected ]
[ 53.433865] 4.3.0-rc6 #96 Not tainted
[ 53.437686] -------------------------------------------------------
[ 53.444220] modprobe/372 is trying to acquire lock:
[ 53.449320] (&new->lock){+.+...}, at: [<c043fe4c>] del_mtd_blktrans_dev+0x80/0xdc
[ 53.457271]
[ 53.457271] but task is already holding lock:
[ 53.463372] (mtd_table_mutex){+.+.+.}, at: [<c0439994>] del_mtd_device+0x18/0x100
[ 53.471321]
[ 53.471321] which lock already depends on the new lock.
[ 53.471321]
[ 53.479856]
[ 53.479856] the existing dependency chain (in reverse order) is:
[ 53.487660]
-> #1 (mtd_table_mutex){+.+.+.}:
[ 53.492331] [<c043fc5c>] blktrans_open+0x34/0x1a4
[ 53.497879] [<c01afce0>] __blkdev_get+0xc4/0x3b0
[ 53.503364] [<c01b0bb8>] blkdev_get+0x108/0x320
[ 53.508743] [<c01713c0>] do_dentry_open+0x218/0x314
[ 53.514496] [<c0180454>] path_openat+0x4c0/0xf9c
[ 53.519959] [<c0182044>] do_filp_open+0x5c/0xc0
[ 53.525336] [<c0172758>] do_sys_open+0xfc/0x1cc
[ 53.530716] [<c000f740>] ret_fast_syscall+0x0/0x1c
[ 53.536375]
-> #0 (&new->lock){+.+...}:
[ 53.540587] [<c063f124>] mutex_lock_nested+0x38/0x3cc
[ 53.546504] [<c043fe4c>] del_mtd_blktrans_dev+0x80/0xdc
[ 53.552606] [<c043f164>] blktrans_notify_remove+0x7c/0x84
[ 53.558891] [<c04399f0>] del_mtd_device+0x74/0x100
[ 53.564544] [<c043c670>] del_mtd_partitions+0x80/0xc8
[ 53.570451] [<c0439aa0>] mtd_device_unregister+0x24/0x48
[ 53.576637] [<c046ce6c>] spi_drv_remove+0x1c/0x34
[ 53.582207] [<c03de0f0>] __device_release_driver+0x88/0x114
[ 53.588663] [<c03de19c>] device_release_driver+0x20/0x2c
[ 53.594843] [<c03dd9e8>] bus_remove_device+0xd8/0x108
[ 53.600748] [<c03dacc0>] device_del+0x10c/0x210
[ 53.606127] [<c03dadd0>] device_unregister+0xc/0x20
[ 53.611849] [<c046d878>] __unregister+0x10/0x20
[ 53.617211] [<c03da868>] device_for_each_child+0x50/0x7c
[ 53.623387] [<c046eae8>] spi_unregister_master+0x58/0x8c
[ 53.629578] [<c03e12f0>] release_nodes+0x15c/0x1c8
[ 53.635223] [<c03de0f8>] __device_release_driver+0x90/0x114
[ 53.641689] [<c03de900>] driver_detach+0xb4/0xb8
[ 53.647147] [<c03ddc78>] bus_remove_driver+0x4c/0xa0
[ 53.652970] [<c00cab50>] SyS_delete_module+0x11c/0x1e4
[ 53.658976] [<c000f740>] ret_fast_syscall+0x0/0x1c
[ 53.664621]
[ 53.664621] other info that might help us debug this:
[ 53.664621]
[ 53.672979] Possible unsafe locking scenario:
[ 53.672979]
[ 53.679169] CPU0 CPU1
[ 53.683900] ---- ----
[ 53.688633] lock(mtd_table_mutex);
[ 53.692383] lock(&new->lock);
[ 53.698306] lock(mtd_table_mutex);
[ 53.704658] lock(&new->lock);
[ 53.707946]
[ 53.707946] *** DEADLOCK ***

Fixes: 073db4a51ee4 ("mtd: fix: avoid race condition when accessing mtd->usecount")
Reported-by: Felipe Balbi <balbi@ti.com>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: <stable@vger.kernel.org>

mtd: blktrans: fix multiplication overflow

In drivers/mtd/mtd_blkdevs.c:
406 set_capacity(gd, (new->size * tr->blksize) >> 9);
The type of new->size is unsigned long and the type of tr->blksize is int,
the result of 'new->size * tr->blksize' may exceed ULONG_MAX on 32bit
machines.

I use nand chip MT29F32G08CBADBWP which is 4GB and the parameters passed
to kernel is 'mtdparts=gpmi-nand:-(user)', the whole nand chip will be
treated as a 4GB mtd partition. new->size is 0x800000 and tr->blksize is
0x200, 'new->size * tr->blksize' however is 0. This is what we do not want
to see.

Using type cast u64 to fix the multiplication overflow issue.

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: blkdevs: fix switch-bool compilation warning

With gcc 5.1 I get:
warning: switch condition has boolean value [-Wswitch-bool]

Signed-off-by: Tomer Barletz <barletz@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

block: have drivers use blk_queue_max_discard_sectors()

Some drivers use it now, others just set the limits field manually.
But in preparation for splitting this into a hard and soft limit,
ensure that they all call the proper function for setting the hw
limit for discards.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

mtd: blktrans: use better error code for unimplemented ioctl()

In commit 50183936254b ("mtd: blktrans: change blktrans_getgeo return
value") we fixed the problem that ioctl(HDIO_GETGEO) might return 0
(success) for mtdblock devices which did not implement the feature and
would leave a blank (zero) result.

But now, let's get the error code right. Other code paths on this ioctl
tend to use -ENOTTY to notify the user that the ioctl() is not supported
for the device, so let's use that instead of -EOPNOTSUPP.

Suggested-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: blktrans: change blktrans_getgeo return value

Modify function blktrans_getgeo()'s return value to -EOPNOTSUPP when
dev->tr->getgeo == NULL.

We shouldn't make the return value to 0 when dev->tr->getgeo == NULL,
because the function blktrans_getgeo() has an output value "hd_geometry"
which is usually used by some application, if returns 0 (i.e.,
"success"), it will make some application get the wrong information.

Signed-off-by: Wenlin Kang <wenlin.kang@windriver.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: fix: avoid race condition when accessing mtd->usecount

On A MIPS 32-cores machine a BUG_ON was triggered because some acesses to
mtd->usecount were done without taking mtd_table_mutex.
kernel: Call Trace:
kernel: [<ffffffff80401818>] __put_mtd_device+0x20/0x50
kernel: [<ffffffff804086f4>] blktrans_release+0x8c/0xd8
kernel: [<ffffffff802577e0>] __blkdev_put+0x1a8/0x200
kernel: [<ffffffff802579a4>] blkdev_close+0x1c/0x30
kernel: [<ffffffff8022006c>] __fput+0xac/0x250
kernel: [<ffffffff80171208>] task_work_run+0xd8/0x120
kernel: [<ffffffff8012c23c>] work_notifysig+0x10/0x18
kernel:
kernel:
Code: 2442ffff ac8202d8 000217fe <00020336> dc820128 10400003
00000000 0040f809 00000000
kernel: ---[ end trace 080fbb4579b47a73 ]---

Fixed by taking the mutex in blktrans_open and blktrans_release.

Note that this locking is already suggested in
include/linux/mtd/blktrans.h:

struct mtd_blktrans_ops {
...
/* Called with mtd_table_mutex held; no race with add/remove */
int (*open)(struct mtd_blktrans_dev *dev);
void (*release)(struct mtd_blktrans_dev *dev);
...
};

But we weren't following it.

Originally reported by (and patched by) Zhang and Giuseppe,
independently. Improved and rewritten.

Cc: stable@vger.kernel.org
Reported-by: Zhang Xingcai <zhangxingcai@huawei.com>
Reported-by: Giuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com>
Tested-by: Giuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: blkdevs: remove dead code

The only exit (break) from the preceding loop is nested within a
condition which yields req == NULL. This code is dead.

Coverity CID #752669

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

block: disable entropy contributions for nonrot devices

Clear QUEUE_FLAG_ADD_RANDOM in all block drivers that set
QUEUE_FLAG_NONROT.

Historically, all block devices have automatically made entropy
contributions. But as previously stated in commit e2e1a148 ("block: add
sysfs knob for turning off disk entropy contributions"):
- On SSD disks, the completion times aren't as random as they
are for rotational drives. So it's questionable whether they
should contribute to the random pool in the first place.
- Calling add_disk_randomness() has a lot of overhead.

There are more reliable sources for randomness than non-rotational block
devices. From a security perspective it is better to err on the side of
caution than to allow entropy contributions from unreliable "random"
sources.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

mtd: mtd_blkdevs: handle REQ_FLUSH request and do explicit flush of writeback buffer

mtd_blkdevs is device with volatile cache (writeback buffer), so it should support
REQ_FLUSH to do explicit flush.

Without this patch 'sync' does not guarantee that writeback buffer will be flushed
on disk in case of power off, e.g.:

$ cp some_file /mnt
$ sync

### POWER OFF

In case of this sequence writeback buffer will not be flushed on disk.

This patch fixes this behaviour and explicitly reports to block layer that flush
requests are being supported.

Signed-off-by: Roman Peniaev <r.peniaev@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

block: remove struct request buffer member

This was used in the olden days, back when onions were proper
yellow. Basically it mapped to the current buffer to be
transferred. With highmem being added more than a decade ago,
most drivers map pages out of a bio, and rq->buffer isn't
pointing at anything valid.

Convert old style drivers to just use bio_data().

For the discard payload use case, just reference the page
in the bio.

Signed-off-by: Jens Axboe <axboe@fb.com>

mtd: delete non-required instances of include <linux/init.h>

None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>. Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
[Brian: dropped one incorrect hunk]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

block_device_operations->release() should return void

The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

mtd_blktrans_ops->release() should return void

Both existing instances always return 0 and even if they didn't,
the value would be lost on the way out. Just don't bother...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

mtd: mtd_blkdevs: Replace request handler kthread with a workqueue

By replacing a kthread with a workqueue, the code is now a bit clearer.
There's also a slight reduction of code size (numbers apply for x86):
Before:
text data bss dec hex filename
3248 36 0 3284 cd4 drivers/mtd/mtd_blkdevs.o

After:
text data bss dec hex filename
3150 36 0 3186 c72 drivers/mtd/mtd_blkdevs.o

Due to lack of real hardware, tests have been performed on an emulated
environment with mtdswap and mtdblock over nandsim devices.
Some real testing should be done, before merging this patch.

Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

mtd: mtd_blkdev: Use a different name for block_device_operations variable

struct mtd_blktrans_ops is a type, and mtd_blktrans_ops is a variable.
To improve code clarity it's better to not use the same names,
so we just change the latter.

Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

mtd: mtdblock: call mtd_sync() only if opened for write

Because it is useless to call it if the device is opened in R/O mode, and also
harmful: on CFI NOR flash it may block for long time waiting for erase
operations to complete is another partition with a R/W file-system on this
chip.

Artem Bityutskiy: write commit message, amend the patch to match the latest
tree (we use mtd_sync(), not mtd->sync() nowadays).

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtd_blkdevs: don't increase 'open' count on error path

Some error paths in mtd_blkdevs were fixed in the following commit:

commit 94735ec4044a6d318b83ad3c5794e931ed168d10
mtd: mtd_blkdevs: fix error path in blktrans_open

But on these error paths, the block device's `dev->open' count is
already incremented before we check for errors. This meant that, while
the error path was handled correctly on the first time through
blktrans_open(), the device is erroneously considered already open on
the second time through.

This problem can be seen, for instance, when a UBI volume is
simultaneously mounted as a UBIFS partition and read through its
corresponding gluebi mtdblockX device. This results in blktrans_open()
passing its error checks (with `dev->open > 0') without actually having
a handle on the device. Here's a summarized log of the actions and
results with nandsim:

# modprobe nandsim
# modprobe mtdblock
# modprobe gluebi
# modprobe ubifs
# ubiattach /dev/ubi_ctrl -m 0
...
# ubimkvol /dev/ubi0 -N test -s 16MiB
...
# mount -t ubifs ubi0:test /mnt
# ls /dev/mtdblock*
/dev/mtdblock0 /dev/mtdblock1
# cat /dev/mtdblock1 > /dev/null
cat: can't open '/dev/mtdblock4': Device or resource busy
# cat /dev/mtdblock1 > /dev/null

CPU 0 Unable to handle kernel paging request at virtual address
fffffff0, epc == 8031536c, ra == 8031f280
Oops[#1]:
...
Call Trace:
[<8031536c>] ubi_leb_read+0x14/0x164
[<8031f280>] gluebi_read+0xf0/0x148
[<802edba8>] mtdblock_readsect+0x64/0x198
[<802ecfe4>] mtd_blktrans_thread+0x330/0x3f4
[<8005be98>] kthread+0x88/0x90
[<8000bc04>] kernel_thread_helper+0x10/0x18

Cc: stable@kernel.org [3.0+]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mark block device queue as non-rotational

This is similar to what the nbd driver does, among others.

Signed-off-by: Dan McGee <dpmcgee@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>

mtd: mtd_blkdevs: fix error path in blktrans_open

The 'blktrans_open()' does not handle possible '__get_mtd_device()' failures
because it does not check the error code. Moreover, the 'dev->tr->open()'
failures are not handled correctly because in this case the function just
goes ahead and gets the mtd device, then returns an error. But Instead, it
should _not_ try to get the mtd device, then it should put back the module
and the kref.

This patch fixes the issue. Note, I only compile-tested it. This patch was
inspired by a bug report about a similar issue in 2.6.34 kernels
sent by Mike Turner <admin@islandsoftware.co.uk> to the MTD mailing list:

http://lists.infradead.org/pipermail/linux-mtd/2011-April/034980.html

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd_blkdevs: Set the maximum discards size

Set max_discard_sectors to UINT_MAX.

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd_blkdevs: Add background processing support

Add a new background method into mtd_blktrans_ops, add background support
into mtd_blktrans_thread(), and add mtd_blktrans_cease_background().

If the mtd blktrans dev has the background support, the thread will
call background function when the request queue becomes empty. The background
operation may run as long as needs to until
mtd_blktrans_cease_background() tells to stop.

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtd_blkdevs: local symbols should be static

The function blktrans_dev_release and blktrans_dev_put are only used
locally in this file and should be static.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtd_blkdevs: fix double free on error path

This one liner patch fixes double free that will occur if add_mtd_blktrans_dev
fails. On failure it frees the input argument, but all its users also free it
on error which is natural thing to do. Thus don't free it.

All credit for finding that bug belongs to reporters of the bug in the android bugzilla
http://code.google.com/p/android/issues/detail?id=13761

Commit message tweaked by Artem.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org

mtd: Remove redundant mutex from mtd_blkdevs.c

In commit 2a48fc0ab24241755dc93bfd4f01d68efab47f5a ('block: autoconvert
trivial BKL users to private mutex'), Arnd replaced the BKL usage with a
mutex. However, Maxim has already provided a better fix in commit
480792b7bf188c29b8d4b10fee65c3a06ec5dbf7 ('mtd: blktrans: kill BKL'),
which was simply to remove the BKL without replacing it — since he'd
already made it do all necessary locking for itself.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

MTD: Fix wrong check register_blkdev return value

register_blkdev return 1..255 when major = 0.

if (ret ) {
printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
tr->name, tr->major, ret);
mutex_unlock(&mtd_table_mutex);
return ret;
}

Above code will return fail when register_blkdev return allocated major number.

Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: blktrans: fix a race vs kthread_stop

There is small race window that could make kthread_stop hang forever.
I found that while hacking the IR subsystem.

Signed-off-by: Maxim Levitsky <maximlevisky@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: blktrans: kill BKL

It not needed, because I already added locking for all fops
methods.

Signed-off-by: Maxim Levitsky <maximlevisky@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: allow to unload the mtdtrans module if its block devices aren't open

Now it once again possible to remove mtdtrans module.
You still need to ensure that block devices of that module aren't mounted.
This is due to the fact that as long as a block device is open, it still exists,
therefore if we were to allow module removal, this block device might became used again.

This time in addition to code review, I also made the code
pass some torture tests like module reload in a loop + read in a loop +
card insert/removal all at same time.

The blktrans_open/blktrans_release don't take the mtd table lock because:

While device is added (that includes execution of add_mtd_blktrans_dev)
the lock is already taken

Now suppose the device will never be removed. In this case even if we have changes
in mtd table, the entry that we need will stay exactly the same. (Note that we don't
look at table at all, just following private pointer of block device).

Now suppose that someone tries to remove the mtd device.
This will be propagated to trans driver which _ought_ to call del_mtd_blktrans_dev
which will take the per device lock, release the mtd device and set trans->mtd = NULL.
>From this point on, following opens won't even be able to know anything about that mtd device
(which at that point is likely not to exist)
Also the same care is taken not to trip over NULL mtd pointer in blktrans_dev_release.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

block: autoconvert trivial BKL users to private mutex

The block device drivers have all gained new lock_kernel
calls from a recent pushdown, and some of the drivers
were already using the BKL before.

This turns the BKL into a set of per-driver mutexes.
Still need to check whether this is safe to do.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
if grep -q 'include.*linux.mutex.h' ${file} ; then
sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
else
sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
fi
sed -i ${file} \
-e "/^#include.*linux.mutex.h/,$ {
1,/^\(static\|int\|long\)/ {
/^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }" \
-e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
-e '/[ ]*cycle_kernel_lock();/d'
else
sed -i -e '/include.*\<smp_lock.h\>/d' ${file} \
-e '/cycle_kernel_lock()/d'
fi

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

mtd: Update copyright notices

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

block: push down BKL into .open and .release

The open and release block_device_operations are currently
called with the BKL held. In order to change that, we must
first make sure that all drivers that currently rely
on this have no regressions.

This blindly pushes the BKL into all .open and .release
operations for all block drivers to prepare for the
next step. The drivers can subsequently replace the BKL
with their own locks or remove it completely when it can
be shown that it is not needed.

The functions blkdev_get and blkdev_put are the only
remaining users of the big kernel lock in the block
layer, besides a few uses in the ioctl code, none
of which need to serialize with blkdev_{get,put}.

Most of these two functions is also under the protection
of bdev->bd_mutex, including the actual calls to
->open and ->release, and the common code does not
access any global data structures that need the BKL.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: push down BKL into .locked_ioctl

As a preparation for the removal of the big kernel
lock in the block layer, this removes the BKL
from the common ioctl handling code, moving it
into every single driver still using it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: remove wrappers for request type/flags

Remove all the trivial wrappers for the cmd_type and cmd_flags fields in
struct requests. This allows much easier grepping for different request
types instead of unwinding through macros.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

mtd: blkdevs: fix crash related to sysfs attributes.

Remove the attributes group before disk to avoid use after free

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: return success on blktrans_ioctl

There was a break missing so we returned -ENOTTY on success instead of
zero. This was introduced by 048d8719956: "mtd: blktrans: Hotplug fixes"

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: blktrans: do blk_cleanup_queue when it is really safe to do so

I was calling it in del_mtd_blktrans_dev, but ->request_fn could
still be running at that point, thus defer this call
to blktrans_dev_release

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: Few follow up cleanups for Smartmedia/xD support

* Test results of few functions that were declared with __must_check
* Fix bogus gcc warning about uinitialized variable 'ret'
* Remove unused variable from mtdblock_remove_dev
* Don't use deprecated DMA_32BIT_MASK

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: blktrans: allow FTL drivers to export sysfs attributes

This patch adds an ability to export sysfs attributes below
the block disk device.

This can be used to pass the udev an information about the FTL
and could include the vendor, serial, version, etc...

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: blktrans: Hotplug fixes

* Add locking where it was missing.

* Don't do a get_mtd_device in blktrans_open because it would lead to a
deadlock; instead do that in add_mtd_blktrans_dev.

* Only free the mtd_blktrans_dev structure when the last user exits.

* Flush request queue on device removal.

* Track users, and call tr->release in del_mtd_blktrans_dev
Due to that ->open and release aren't called more that once.

Now it is safe to call del_mtd_blktrans_dev while the device is still in use.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: blktrans: remove mtd_blkcore_priv, switch to per device queue and thread

This is the biggest change. To make hotplug possible, and this layer
clean, the mtd_blktrans_dev now contains everything for a single mtd
block translation device. Also removed some very old leftovers.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: Raise limit on block device minor numbers

add_mtd_blktrans_dev() imposes a maximum of 257 devices per block
translator. This was presumably meant to prevent overflow back in the
days of 8-bit minor numbers. Instead, check against MINORMASK and the
limits of the partition naming scheme.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: Introduce and use iteration macro for reading the MTD device table

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: don't use PF_MEMALLOC

Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few
memory, anyone must not prevent it. Otherwise the system cause
mysterious hang-up and/or OOM Killer invokation.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

block: add helpers to run flush_dcache_page() against a bio and a request's pages

Mtdblock driver doesn't call flush_dcache_page for pages in request. So,
this causes problems on architectures where the icache doesn't fill from
the dcache or with dcache aliases. The patch fixes this.

The ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE symbol was introduced to avoid
pointless empty cache-thrashing loops on architectures for which
flush_dcache_page() is a no-op. Every architecture was provided with this
flush pages on architectires where ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE is
equal 1 or do nothing otherwise.

See "fix mtd_blkdevs problem with caches on some architectures" discussion
on LKML for more information.

Signed-off-by: Ilya Loginov <isloginov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Peter Horton <phorton@bitbox.co.uk>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

mtd_blkdevs.c: quiet a "symbol shadows" sparse warning

In register_mtd_blktrans(), the symbol 'ret' is already declared
as an int at the start of the function. The inner loop declaration
is unnecessary. Quiets the following sparse warning:

warning: symbol 'ret' shadows an earlier one

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

block: use normal I/O path for discard requests

prepare_discard_fn() was being called in a place where memory allocation
was effectively impossible. This makes it inappropriate for all but
the most trivial translations of Linux's DISCARD operation to the block
command set. Additionally adding a payload there makes the ownership
of the bio backing unclear as it's now allocated by the device driver
and not the submitter as usual.

It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether
the queue supports discard operations or not. blkdev_issue_discard now
allocates a one-page, sector-length payload which is the right thing
for the common ATA and SCSI implementations.

The mtd implementation of prepare_discard_fn() is replaced with simply
checking for the request being a discard.

Largely based on a previous patch from Matthew Wilcox <matthew@wil.cx>
which did the prepare_discard_fn but not the different payload allocation
yet.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: use normal I/O path for discard requests

prepare_discard_fn() was being called in a place where memory allocation
was effectively impossible. This makes it inappropriate for all but
the most trivial translations of Linux's DISCARD operation to the block
command set. Additionally adding a payload there makes the ownership
of the bio backing unclear as it's now allocated by the device driver
and not the submitter as usual.

It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether
the queue supports discard operations or not. blkdev_issue_discard now
allocates a one-page, sector-length payload which is the right thing
for the common ATA and SCSI implementations.

The mtd implementation of prepare_discard_fn() is replaced with simply
checking for the request being a discard.

Largely based on a previous patch from Matthew Wilcox <matthew@wil.cx>
which did the prepare_discard_fn but not the different payload allocation
yet.

Signed-off-by: Christoph Hellwig <hch@lst.de>

const: make block_device_operations const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mtd: blkdevs: do not forget to get MTD devices

Nowadays MTD devices have to be "get" before they can be
used. This has to be done with 'get_mtd_device()'. The
'blktrans_open()' function did not do this and instead
used 'try_module_get()'. Fix this.

Since 'get_mtd_device()' already gets the module, extra
'try_module_get()' is not needed.

This fixes oops when one tries to use mtdblock on top of
gluebi.

Reported-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] set blkdev parent to the mtd device, not its parent

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

block: Do away with the notion of hardsect_size

Until now we have had a 1:1 mapping between storage device physical
block size and the logical block sized used when addressing the device.
With SATA 4KB drives coming out that will no longer be the case. The
sector size will be 4KB but the logical block size will remain
512-bytes. Hence we need to distinguish between the physical block size
and the logical ditto.

This patch renames hardsect_size to logical_block_size.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: implement and enforce request peek/start/fetch

Till now block layer allowed two separate modes of request execution.
A request is always acquired from the request queue via
elv_next_request(). After that, drivers are free to either dequeue it
or process it without dequeueing. Dequeue allows elv_next_request()
to return the next request so that multiple requests can be in flight.

Executing requests without dequeueing has its merits mostly in
allowing drivers for simpler devices which can't do sg to deal with
segments only without considering request boundary. However, the
benefit this brings is dubious and declining while the cost of the API
ambiguity is increasing. Segment based drivers are usually for very
old or limited devices and as converting to dequeueing model isn't
difficult, it doesn't justify the API overhead it puts on block layer
and its more modern users.

Previous patches converted all block low level drivers to dequeueing
model. This patch completes the API transition by...

* renaming elv_next_request() to blk_peek_request()

* renaming blkdev_dequeue_request() to blk_start_request()

* adding blk_fetch_request() which is combination of peek and start

* disallowing completion of queued (not started) requests

* applying new API to all LLDs

Renamings are for consistency and to break out of tree code so that
it's apparent that out of tree drivers need updating.

[ Impact: block request issue API cleanup, no functional change ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: unsik Kim <donari75@gmail.com>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Laurent Vivier <Laurent@lvivier.info>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Stefan Weinhuber <wein@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

mtd_blkdevs: dequeue in-flight request

mtd_blkdevs processes requests one-by-one synchronously from a kthread
and can be easily converted to dequeueing model. Convert it.

[ Impact: dequeue in-flight request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: blk_rq_[cur_]_{sectors|bytes}() usage cleanup

With the previous changes, the followings are now guaranteed for all
requests in any valid state.

* blk_rq_sectors() == blk_rq_bytes() >> 9
* blk_rq_cur_sectors() == blk_rq_cur_bytes() >> 9

Clean up accessor usages. Notable changes are

* nbd,i2o_block: end_all used instead of explicit byte count
* scsi_lib: unnecessary conditional on request type removed

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: convert to pos and nr_sectors accessors

With recent cleanups, there is no place where low level driver
directly manipulates request fields. This means that the 'hard'
request fields always equal the !hard fields. Convert all
rq->sectors, nr_sectors and current_nr_sectors references to
accessors.

While at it, drop superflous blk_rq_pos() < 0 test in swim.c.

[ Impact: use pos and nr_sectors accessors ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Mike Miller <mike.miller@hp.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Dario Ballabio <ballabio_dario@emc.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: unsik Kim <donari75@gmail.com>
Cc: Laurent Vivier <Laurent@lvivier.info>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: replace end_request() with [__]blk_end_request_cur()

end_request() has been kept around for backward compatibility;
however, it's about time for it to go away.

* There aren't too many users left.

* Its use of @updtodate is pretty confusing.

* In some cases, newer code ends up using mixture of end_request() and
[__]blk_end_request[_all](), which is way too confusing.

So, add [__]blk_end_request_cur() and replace end_request() with it.
Most conversions are straightforward. Noteworthy ones are...

* paride/pcd: next_request() updated to take 0/-errno instead of 1/0.

* paride/pf: pf_end_request() and next_request() updated to take
0/-errno instead of 1/0.

* xd: xd_readwrite() updated to return 0/-errno instead of 1/0.

* mtd/mtd_blkdevs: blktrans_discard_request() updated to return
0/-errno instead of 1/0. Unnecessary local variable res
initialization removed from mtd_blktrans_thread().

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Joerg Dorchain <joerg@dorchain.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Laurent Vivier <Laurent@lvivier.info>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: unsik Kim <donari75@gmail.com>

[MTD] driver model updates

Update driver model support in the MTD framework, so it fits
better into the current udev-based hotplug framework:

- Each mtd_info now has a device node. MTD drivers should set
the dev.parent field to point to the physical device, before
setting up partitions or otherwise declaring MTDs.

- Those device nodes always map to /sys/class/mtdX device nodes,
which no longer depend on MTD_CHARDEV.

- Those mtdX sysfs nodes have a "starter set" of attributes;
it's not yet sufficient to replace /proc/mtd.

- Enabling MTD_CHARDEV provides /sys/class/mtdXro/ nodes and the
/sys/class/mtd*/dev attributes (for udev, mdev, etc).

- Include a MODULE_ALIAS_CHARDEV_MAJOR macro. It'll work with
udev creating the /dev/mtd* nodes, not just a static rootfs.

So the sysfs structure is pretty much what you'd expect, except
that readonly chardev nodes are a bit quirky.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] fix use after free in register_mtd_blktrans

Reported-by: Dan Carpenter <error27@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[PATCH] switch mtd_blkdevs

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[PATCH] beginning of methods conversion

To keep the size of changesets sane we split the switch by drivers;
to keep the damn thing bisectable we do the following:
1) rename the affected methods, add ones with correct
prototypes, make (few) callers handle both. That's this changeset.
2) for each driver convert to new methods. *ALL* drivers
are converted in this series.
3) kill the old (renamed) methods.

Note that it _is_ a flagday; all in-tree drivers are converted and by the
end of this series no trace of old methods remain. The only reason why
we do that this way is to keep the damn thing bisectable and allow per-driver
debugging if anything goes wrong.

New methods:
open(bdev, mode)
release(disk, mode)
ioctl(bdev, mode, cmd, arg) /* Called without BKL */
compat_ioctl(bdev, mode, cmd, arg)
locked_ioctl(bdev, mode, cmd, arg) /* Called with BKL, legacy */

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Support 'discard sectors' operation in translation layer support core

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

[MTD] Use list_for_each_entry[_safe] where appropriate.

Janitorial work to remove temporary pointers and make some functions a bit
more readable.

Signed-off-by: Chris Malley <mail@chrismalley.co.uk>
Reviewed-By: Jörn Engel <joern@logfs.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

MTD/JFFS2: remove CVS keywords

Once upon a time, the MTD repository was using CVS.

This patch therefore removes all usages of the no longer updated CVS
keywords from the MTD code.

This also includes code that printed them to the user.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] Always initialise mutex in new mtd_blktrans_dev.

We were only initialising the mutex in the case where the new device was
automatically allocated the highest minor number. If the caller
specified a minor number, or if it filled in a free slot which was made
by a previous device deregistering, the mutex wouldn't get initialised
when we jumped out of the loop.

Reported by Monte Copeland <catboat@texas.net>

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Freezer: make kernel threads nonfreezable by default

Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves. This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.

It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.

The patch causes all kernel threads to be nonfreezable by default (ie. to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE. It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear. Additionally, it updates documentation to
describe the freezing of tasks more accurately.

[akpm@linux-foundation.org: build fixes]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[MTD] mtdcore.c: share syms with mtd_blkdev.c

Fix the sparse warnings generated by the implicit
dependency of mtd_blkdevs.c and mtd_core.c for the
two symbols mtd_table and mtd_table_mutex. This is
done by adding an local header file mtdcore.h to
define these (including the warning about the
non-proliferation of these symbols).

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtd_blkdevs.c: do not export 'mtd_blktrans_ops'

The mtd_blktrans_ops is not defined in any of the headers
and is indeed not used elsewhere in the kernel, so mark it
as static to reduce the warnings from sparse

drivers/mtd/mtd_blkdevs.c:204:32: warning: symbol 'mtd_blktrans_ops' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Clean up mutex_trylock noise

Ingo Molnar's semaphore to mutex conversions left some noise on a few
trylock calls. Clean it up.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[MTD] Finish conversion mtd_blkdevs to use the kthread API

Remove waitqueue, 'exiting' flag and completion; use kthread APIs instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtd_blkdevs: Convert to use the kthread API

thread_run is used intead of kernel_thread, daemonize, and mucking
around blocking signals directly.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] replace kmalloc+memset with kzalloc

Signed-off-by: Yan Burman <yan_952@hotmail.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] Allow variable block sizes in mtd_blkdevs

Currently, mtd_blkdevs enforces a block size of 512, even if the drivers
can seemingly request a different size. This patch fixes mtd_blkdevs so
block sizes other than 512 work correctly.

Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] fix printk warning

gcc spits out this warning:

drivers/mtd/mtd_blkdevs.c: In function ‘do_blktrans_request’:
drivers/mtd/mtd_blkdevs.c:72: warning: format ‘%ld’ expects type ‘long int’, but argument 2 has type ‘unsigned int’

This could be fixed any number of ways, including use of BUG().
rq_data_dir() only returns 0 or 1, so this entire case is superfluous.
I did the most simple fix.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[PATCH] Split struct request ->flags into two parts

Right now ->flags is a bit of a mess: some are request types, and
others are just modifiers. Clean this up by splitting it into
->cmd_type and ->cmd_flags. This allows introduction of generic
Linux block message types, useful for sending generic Linux commands
to block devices.

Signed-off-by: Jens Axboe <axboe@suse.de>

Revert "[MTD] blkdev helper code: fix printk format warning"

This reverts commit 668040fcd1e06fc3e68a92708cbdfa5a52c37d3c.

The 'flags' field of the struct request is 'unsigned long'. Quite
how Randy came to see 'long int format, different type arg' I don't
know, but it doesn't seem to be the case any more.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] blkdev helper code: fix printk format warning

Fix printk format warning(s):
drivers/mtd/mtd_blkdevs.c:72: warning: long int format, different type arg (arg 2)

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[PATCH] sem2mutex: drivers/mtd/

Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

BUG_ON() Conversion in drivers/mtd/

this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

[PATCH] Add block_device_operations.getgeo block device method

HDIO_GETGEO is implemented in most block drivers, and all of them have to
duplicate the code to copy the structure to userspace, as well as getting
the start sector. This patch moves that to common code [1] and adds a
->getgeo method to fill out the raw kernel hd_geometry structure. For many
drivers this means ->ioctl can go away now.

[1] the s390 block drivers are odd in this respect. xpram sets ->start
to 4 always which seems more than odd, and the dasd driver shifts
the start offset around, probably because of it's non-standard
sector size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@suse.de>
Cc: <mike.miller@hp.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[MTD] core: Clean up trailing white spaces

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

[MTD] mtd_blkdevs.c: Fix names when many devices/partitions are created

mtdblock (and other mtd modules that use the mtd_blkdevs interface
between the mtd translation layers and the linux block layer) handles
incorrectly more than 10 devices or 26 partitions in the names passed to
the generic disk layer. This causes the device file names and other
info kept by the generic disk/block layers to have names such as
"mtdblock<". Use integer formatting for device numbers; use "aa-az"
for partitions 27-52, "ba-bz" for 53-78...

Signed-off-by: Todd Poynor <tpoynor@mvista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

[MTD] mtd_blkdevs.c: Remove DEVFS leftovers

Remove mtd_blkdevs refs to the no longer functional DEVFS filesystem.

Verified mtdblock continues to work fine via udev with these calls
removed.

Signed-off-by: Todd Poynor <tpoynor@mvista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!