If the original submission (or allocation) of the URBs for a SCSI
command fails, the UAS driver sticks the command structure in a
workqueue and schedules uas_do_work() to run.  That function removes the
entire queue before walking across it and attempting to resubmit.

Unfortunately, if the second submission fails, we will leak memory
(because an allocated URB was not submitted) and possibly leave the SCSI
command partially enqueued on some of the stream rings.  Fix this by
checking whether the second submission failed and re-queueing the
command to the UAS workqueue and scheduling it.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

The situation up to this point meant that module.h was pretty
much everywhere, regardless of whether you asked for it or not.
We are fixing that, so give the USB folks who want it an actual
include of it.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

If swap is on a UAS device, we could recurse into the driver by using
GFP_KERNEL.  Using GFP_NOIO ensures we won't.
Reported-by: NJames Bottomley <James.Bottomley@suse.de>
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

While all existing UAS devices use alternate interface 1, this is not
guaranteed, and it has caused confusion with people trying to bind the
uas driver to non-uas devices.
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The spec calls this the status pipe.  While it is used to receive sense IUs,
it is also used to receive other IUs, so this can be confusing.
Reported-by: NLuben Tuikov <ltuikov@yahoo.com>
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The IUs are not being fully initialised by the driver (due to the reserved
space).  Since we should be zeroing reserved fields, use kzalloc to do
it for us.
Reported-by: NLuben Tuikov <ltuikov@yahoo.com>
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add a comment to the Sense IU data structure that it's also used for Read
Ready and Write Ready.  Remove the 'service response' element since it's
gone from the current draft (04).
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Move the mid-layer's ->queuecommand() invocation from being locked
with the host lock to being unlocked to facilitate speeding up the
critical path for drivers who don't need this lock taken anyway.

The patch below presents a simple SCSI host lock push-down as an
equivalent transformation.  No locking or other behavior should change
with this patch.  All existing bugs and locking orders are preserved.

Additionally, add one parameter to queuecommand,
	struct Scsi_Host *
and remove one parameter from queuecommand,
	void (*done)(struct scsi_cmnd *)

Scsi_Host* is a convenient pointer that most host drivers need anyway,
and 'done' is redundant to struct scsi_cmnd->scsi_done.

Minimal code disturbance was attempted with this change.  Most drivers
needed only two one-line modifications for their host lock push-down.
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>
Acked-by: NJames Bottomley <James.Bottomley@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

REQ_HARDBARRIER is dead now, so remove the leftovers.  What's left
at this point is:

 - various checks inside the block layer.
 - sanity checks in bio based drivers.
 - now unused bio_empty_barrier helper.
 - Xen blockfront use of BLKIF_OP_WRITE_BARRIER - it's dead for a while,
   but Xen really needs to sort out it's barrier situaton.
 - setting of ordered tags in uas - dead code copied from old scsi
   drivers.
 - scsi different retry for barriers - it's dead and should have been
   removed when flushes were converted to FS requests.
 - blktrace handling of barriers - removed.  Someone who knows blktrace
   better should add support for REQ_FLUSH and REQ_FUA, though.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

USB Attached SCSI is a new protocol specified jointly by the SCSI T10
committee and the USB Implementors Forum.
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
[mina86@mina86.com: updated to use new USB_ prefix]
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>