Sujit has found a race condition that would make q->nr_pending
unbalanced, it occurs as Sujit explained:

"
sd_probe_async() ->
	add_disk() ->
		disk_add_event() ->
			schedule(disk_events_workfn)
	sd_revalidate_disk()
	blk_pm_runtime_init()
return;

Let's say the disk_events_workfn() calls sd_check_events() which tries
to send test_unit_ready() and because of sd_revalidate_disk() trying to
send another commands the test_unit_ready() might be re-queued as the
tagged command queuing is disabled.

So the race condition is -

Thread 1 			  |		Thread 2
sd_revalidate_disk()		  |	sd_check_events()
...nr_pending = 0 as q->dev = NULL|	scsi_queue_insert()
blk_runtime_pm_init()		  | 	blk_pm_requeue_request() ->
				  |	nr_pending = -1 since
				  |	q->dev != NULL
"

The problem is, the test_unit_ready request doesn't get counted the
first time it is queued, so the later decrement of q->nr_pending in
blk_pm_requeue_request makes it unbalanced.

Fix this by calling blk_pm_runtime_init before add_disk so that all
requests initiated there will all be counted.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reported-and-tested-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

This patch fixes an out-of-bounds error in sd_read_cache_type(), found
by Google's AddressSanitizer tool.  When the loop ends, we know that
"offset" lies beyond the end of the data in the buffer, so no Caching
mode page was found.  In theory it may be present, but the buffer size
is limited to 512 bytes.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
CC: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

The dev_attrs field of struct class is going away soon, dev_groups
should be used instead.  This converts the scsi disk class code to use
the correct field.

It required some functions to be moved around to place the show and
store functions next to each other, the old order seemed to make no
sense at all.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

sd_prep_fn will allocate a larger CDB for the command via mempool_alloc
for devices using DIF type 2 protection.  This CDB was being freed
in sd_done, which results in a kernel crash if the command is retried
due to a UNIT ATTENTION.  This change moves the code to free the larger
CDB into sd_unprep_fn instead, which is invoked after the request is
complete.

It is no longer necessary to call scsi_print_command separately for
this case as the ->cmnd will no longer be NULL in the normal code path.

Also removed conditional test for DIF type 2 when freeing the larger
CDB because the protection_type could have been changed via sysfs while
the command was executing.

Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

Pull first round of SCSI updates from James Bottomley:
 "The patch set is mostly driver updates (usf, zfcp, lpfc, mpt2sas,
  megaraid_sas, bfa, ipr) and a few bug fixes.  Also of note is that the
  Buslogic driver has been rewritten to a better coding style and 64 bit
  support added.  We also removed the libsas limitation on 16 bytes for
  the command size (currently no drivers make use of this)"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (101 commits)
  [SCSI] megaraid: minor cut and paste error fixed.
  [SCSI] ufshcd-pltfrm: remove unnecessary dma_set_coherent_mask() call
  [SCSI] ufs: fix register address in UIC error interrupt handling
  [SCSI] ufshcd-pltfrm: add missing empty slot in ufs_of_match[]
  [SCSI] ufs: use devres functions for ufshcd
  [SCSI] ufs: Fix the response UPIU length setting
  [SCSI] ufs: rework link start-up process
  [SCSI] ufs: remove version check before IS reg clear
  [SCSI] ufs: amend interrupt configuration
  [SCSI] ufs: wrap the i/o access operations
  [SCSI] storvsc: Update the storage protocol to win8 level
  [SCSI] storvsc: Increase the value of scsi timeout for storvsc devices
  [SCSI] MAINTAINERS: Add myself as the maintainer for BusLogic SCSI driver
  [SCSI] BusLogic: Port driver to 64-bit.
  [SCSI] BusLogic: Fix style issues
  [SCSI] libiscsi: Added new boot entries in the session sysfs
  [SCSI] aacraid: Fix for arrays are going offline in the system. System hangs
  [SCSI] ipr: IOA Status Code(IOASC) update
  [SCSI] sd: Update WRITE SAME heuristics
  [SCSI] fnic: potential dead lock in fnic_is_abts_pending()
  ...

Calling dev_set_name with a single paramter causes it to be handled as a
format string.  Many callers are passing potentially dynamic string
content, so use "%s" in those cases to avoid any potential accidents,
including wrappers like device_create*() and bdi_register().

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

SATA drives located behind a SAS controller would incorrectly receive
WRITE SAME commands. Tweak the heuristics so that:

 - If REPORT SUPPORTED OPERATION CODES is provided we will use that to
   choose between WRITE SAME(16), WRITE SAME(10) and disabled. This also
   fixes an issue with the old code which would issue WRITE SAME(10)
   despite the command not being whitelisted in REPORT SUPPORTED
   OPERATION CODES.

 - If REPORT SUPPORTED OPERATION CODES is not provided we will fall back
   to WRITE SAME(10) unless the device has an ATA Information VPD page.
   The assumption is that a SATL which is smart enough to implement
   WRITE SAME would also provide REPORT SUPPORTED OPERATION CODES.

To facilitate the new heuristics scsi_report_opcode() has been modified
to so we can distinguish between "operation not supported" and "RSOC not
supported".

Reported-by: H. Peter Anvin <hpa@zytor.com>
Tested-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

Commit 39c60a0948cc '[SCSI] sd: fix array cache flushing bug causing
performance problems' added temp as a pointer to "temporary " and used
sizeof(temp) - 1 as its length.  But sizeof(temp) is the size of the
pointer, not the size of the string constant.  Change temp to a static
array so that sizeof() does what was intended.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

When multipathed systems run into an all-paths-down scenario
all devices might be dropped, too. This causes 'del_gendisk'
to be called, which will unregister the kobj_map->probe()
function for all disk device numbers.
When the device comes back the default ->probe() function
is run which will call __request_module(), which will
deadlock.
As 'del_gendisk' typically does _not_ trigger a module unload
the default ->probe() function is pointless anyway.
This patch implements a dummy ->probe() function, which will
just return NULL if the disk is not registered.
This will avoid the deadlock. Plus it'll speed up device
scanning.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

Signed-off-by: James Bottomley <JBottomley@Parallels.com>