scsi: message: fusion: Remove in_interrupt() usage in mptsas_cleanup_fw_event_q()

mptsas_cleanup_fw_event_q() uses in_interrupt() to determine if it is safe
to cancel a worker item.

Aside of that in_interrupt() is deprecated as it does not provide what the
name suggests. It covers more than hard/soft interrupt servicing context
and is semantically ill defined.

Looking closer there are a few problems with the current construct:

- It could be invoked from an interrupt handler / non-blocking context
because cancel_delayed_work() has no such restriction. Also,
mptsas_free_fw_event() has no such restriction.

- The list is accessed unlocked. It may dequeue a valid work-item but at
the time of invoking cancel_delayed_work() the memory may be released or
reused because the worker has already run.

mptsas_cleanup_fw_event_q() is invoked via mptsas_shutdown() which is
always invoked from preemtible context on device shutdown. It is also
invoked via mptsas_ioc_reset(, MPT_IOC_POST_RESET) which is a
MptResetHandlers callback. The only caller here are mpt_SoftResetHandler(),
mpt_HardResetHandler() and mpt_Soft_Hard_ResetHandler(). All these
functions have a `sleepFlag' argument and each caller uses caller uses
`CAN_SLEEP' here and according to current documentation: | @sleepFlag:
Indicates if sleep or schedule must be called

So it is safe to sleep.

Add mptsas_hotplug_event::users member. Initialize it to one by default so
mptsas_free_fw_event() will free the memory. mptsas_cleanup_fw_event_q()
will increment its value for items it dequeues and then it may keep a
pointer after dropping the lock. Invoke cancel_delayed_work_sync() to
cancel the work item and wait if the worker is currently busy. Free the
memory afterwards since it owns the last reference to it.

Link: https://lore.kernel.org/r/20201126132952.2287996-15-bigeasy@linutronix.de
Cc: Sathya Prakash <sathya.prakash@broadcom.com>
Cc: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Cc: Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com>
Cc: MPT-FusionLinux.pdl@broadcom.com
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: message: fusion: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare variable-length
types such as these ones is a flexible array member[1][2], introduced in
C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by this
change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Link: https://lore.kernel.org/r/20200319222533.GA20577@embeddedor.com
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

mptfusion: combine fw_event_work and its event_data

Tack the firmware reply event_data payload to the end of its
corresponding struct fw_event_work allocation. Rework fw_event_work
allocation calculations to include the event_data size where
appropriate.

This clarifies the code a bit and avoids the following smatch warnings:

drivers/message/fusion/mptsas.c:1003 mptsas_queue_device_delete()
error: memcpy() 'fw_event->event_data' too small (29 vs 36)

drivers/message/fusion/mptsas.c:1017 mptsas_queue_rescan() error: not
allocating enough data 168 vs 160

Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Sreekanth Reddy <Sreekanth.Reddy@avagotech.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

[SCSI] mptfusion: Added sanity to check B_T mapping for device before adding to OS

Added sanity check before treating any device is a valid device.
It is possible that firmware can have device page0 in its table, but that
devicemay not be available in topology. Device will be available in topology
only if there is Bus Target mapping is done in firmware. Driver will always
check B_T mapping of firmware before reporting device to upper layer.

Signed-off-by: Kashyap Desai <kashyap.desai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

[SCSI] mptfusion: Event data alignment with 4 byte.

event_data needs to be 4 byte aligned to makes sure there is no unaligned
memory access take place.

Signed-off-by: Kashyap Desai <kashyap.desai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

[SCSI] mpt fusion: Queue full event handling

FW will report Queue full event to Driver and driver will handle this queue
full event to SCSI Mid layer.

Signed-off-by: Kashyap Desai <kadesai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] mpt fusion: RAID device handling and Dual port Raid support is added

1. Handle integrated Raid device(Add/Delete) and error condition and check
related to Raid device. is_logical_volume will represent logical volume
device.
2. Raid device dual port support is added. Main functions to support this
feature are mpt_raid_phys_disk_get_num_paths and mpt_raid_phys_disk_pg1.

Signed-off-by: Kashyap Desai <kadesai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] mpt fusion: Firmware event implementation using seperate WorkQueue

Now Firmware events are handled by firmware event queue.
Previously it was handled in interrupt context/WorkQueue of Linux.
Firmware Event handling is restructured and optimized.

Signed-off-by: Kashyap Desai <kadesai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] mpt fusion: Adding DeviceResetCtx for internal Device reset frame

1.) Added taskmgmt_quiesce_io flag in IOC and removed resetPending from
_MPT_SCSI_HOST struct.
2.) Reset from Scsi mid layer and internal Reset are seperate context.
Adding DeviceResetCtx for internal Device reset frame.
mptsas_taskmgmt_complete is optimized as part of implementation.

Signed-off-by: Kashyap Desai <kadesai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] mpt fusion : Updated copyright statment with 2008 included

Updating copyright statement to include the year 2008

Signed-off-by: Sathya Prakash <sathya.prakash@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] mpt fusion: Creation of mptsas.h header file

The data structure definitions from mptsas.c are moved to a new header
file mptsas.h

signed-off-by: Sathya Prakash <sathya.prakash@lsi.com>
Acked-by: Eric Moore <Eric.Moore@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>