The protocol specific structures and defines which are used by UAS are
moved into a header files by this patch so it can be accessed by the UAS
gadget as well.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>

The UAS driver requires SG support by the HCD operating the device. This
patch stops UAS from operating on a HCD without sg support and prints a
message to let him know.

The spec says:
|For [USB2] backward compatibility, the device shall present [BOT] as
|alternate interface zero (primary) and [UAS] as alternate interface one
|(secondary). A device which does not need backward compatibility with
|[BOT] shall present [UAS] as alternate interface zero. In [USB2]
|systems, the [BOT] driver or an associated filter driver may need to
|issue a SET INTERFACE request for alternate interface one and then allow
|the [UAS] driver to load.

If the user used usb_modeswitch to switch to UAS then he can go back to
BOT or use a different HCD. In case UAS is the only interface then there
is currently no way out.
In future usb_sg_wait() should be extended to provide a non-blocking
interface so it can work with the UAS driver.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>

The status/sense URB is allocated on per-command basis. A read/write
looks the following way on a stream-less connection:

- send cmd tag X, queue status
- receive status, oh it is a read for tag X. queue status & read
- receive read
- receive status, oh I'm done for tag X. Cool call complete and free
  status urb.

This block repeats itself 1:1 for further commands and looks great so
far. Lets take a look now what happens if we do allow multiple commands:

- send cmd tag X, queue statusX (belongs to the command with the X tag)
- send cmd tag Y, queue statusY (belongs to the command with the Y tag)
- receive statusX, oh it is a read for tag X. queue statusX & a read
- receive read
- receive statusY, oh I'm done for tag X. Cool call complete and free statusY.
- receive statusX, oh it is a read for tag Y. queue statusY & before we
  queue the read the the following message can be observed:
  |sd 0:0:0:0: [sda] sense urb submission failure
  followed by a second attempt with the same result.

In order to address this problem we will use only one status URB for
each scsi host in case we don't have stream support (as suggested by
Matthew). This URB is requeued until the device removed. Nothing changes
on stream based endpoints.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

In "usb/uas: use unique tags for all LUNs" we make sure to create unique
tags across all LUNs. This patch uses scsi_host_find_tag() to obtain the
correct command which is associated with the tag.
The following changes are required:
- don't use sdev->current_cmnd anymore
  Since we can have devices which don't support command queueing we must
  ensure that we can tell the two commands apart. Even if a device
  supports comand queuing we send the INQUIRY command "untagged" for
  LUN1 while we can send a tagged command to LUN0 at the same time.
  devinfo->cmnd is used for stashing the one "untagged" command.
- tag number is altered. If stream support is used then the tag number
  must match the stream number. Therefore we can't use tag 0 and must
  start at tag 1.
  In case we have untagged commands (at least the first command) we must
  be able to distinguish between command tag 0 (which becomes 1) and
  untagged command (which becomes curently also 1).
  The following tag numbers are used:
  0: never
  1: for untagged commands (devinfo->cmnd)
  2+: tagged commands.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

I observed that on a device with multiple LUNs UAS was re-using the same
tag number for requests which were issued at the same time to both LUNs.
This patch uses scsi_init_shared_tag_map() to use unique tags for all
LUNs. With this patch I haven't seen the same tag number during the init
sequence anymore. Tag 1 is used for devices which do not adverise
command queueing.
This patch initilizes the queue before adding the scsi host like the
other two user in tree.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

In the UAS status URB completion handler, we need to free the URB, no
matter what happens.  Fix a bug where we would leak the URB (and its
buffer) if we couldn't find a SCSI command that is associated with this
status phase.
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>

UAS can work with either USB 3.0 devices that support bulk streams, or
USB 2.0 devices that do not support bulk streams.  When we're working
with a non-streams device, we need to be able to uniquely identify a
SCSI command with a tag in the IU.  Devices will barf and abort all
queued commands if they find a duplicate tag.

uas_queuecommand_lck() sets cmdinfo->stream to zero if the device
doesn't support streams, which is later passed into uas_alloc_cmd_urb()
as the variable stream.  This means the UAS driver was setting the tag
in all commands to zero for non-stream devices.  So the UAS driver won't
currently work with USB 2.0 devices.

Use the SCSI command tag instead of the stream ID for the command IU
tag.  We have to add one to the SCSI command tag because SCSI tags are
zero-based, but stream IDs are one-based, and the command tag must match
the stream ID that we're queueing the data IUs for.  Untagged SCSI
commands use stream ID 1.
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>

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>

This converts the drivers in drivers/usb/* to use the
module_usb_driver() macro which makes the code smaller and a bit
simpler.

Added bonus is that it removes some unneeded kernel log messages about
drivers loading and/or unloading.

Cc: Simon Arlott <cxacru@fire.lp0.eu>
Cc: Duncan Sands <duncan.sands@free.fr>
Cc: Matthieu CASTET <castet.matthieu@free.fr>
Cc: Stanislaw Gruszka <stf_xl@wp.pl>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Oliver Neukum <oliver@neukum.name>
Cc: Juergen Stuber <starblue@users.sourceforge.net>
Cc: Cesar Miquel <miquel@df.uba.ar>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Michael Hund <mhund@ld-didactic.de>
Cc: Zack Parsons <k3bacon@gmail.com>
Cc: Melchior FRANZ <mfranz@aon.at>
Cc: Tomoki Sekiyama <tomoki.sekiyama@gmail.com>
Cc: Dan Carpenter <error27@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.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>