And require all drivers that want to support BLOCK_PC to allocate it
as the first thing of their private data.  To support this the legacy
IDE and BSG code is switched to set cmd_size on their queues to let
the block layer allocate the additional space.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Rely on the new block layer functionality to allocate additional driver
specific data behind struct request instead of implementing it in SCSI
itѕelf.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Instead do an internal export of __scsi_init_queue for the transport
classes that export BSG nodes.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Currently blk-mq always allocates the sense buffer using normal GFP_KERNEL
allocation.  Refactor the cmd pool code to split the cmd and sense allocation
and share the code to allocate the sense buffers as well as the sense buffer
slab caches between the legacy and blk-mq path.

Note that this switches to lazy allocation of the sense slab caches - the
slab caches (not the actual allocations) won't be destroy until the scsi
module is unloaded instead of keeping track of hosts using them.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Acked-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Without that we'll pass a wrong payload size in cmd->sdb, which
can lead to hangs with drivers that need the total transfer size.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NChris Valean <v-chvale@microsoft.com>
Reported-by: NDexuan Cui <decui@microsoft.com>
Fixes: f9d03f96 ("block: improve handling of the magic discard payload")
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Ensure that if scsi-mq is enabled that scsi_internal_device_block()
waits until ongoing shost->hostt->queuecommand() calls have finished.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Cc: James Bottomley <jejb@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Doug Ledford <dledford@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Instead of allocating a single unused biovec for discard requests, send
them down without any payload.  Instead we allow the driver to add a
"special" payload using a biovec embedded into struct request (unioned
over other fields never used while in the driver), and overloading
the number of segments for this case.

This has a couple of advantages:

 - we don't have to allocate the bio_vec
 - the amount of special casing for discard requests in the block
   layer is significantly reduced
 - using this same scheme for other request types is trivial,
   which will be important for implementing the new WRITE_ZEROES
   op on devices where it actually requires a payload (e.g. SCSI)
 - we can get rid of playing games with the request length, as
   we'll never touch it and completions will work just fine
 - it will allow us to support ranged discard operations in the
   future by merging non-contiguous discard bios into a single
   request
 - last but not least it removes a lot of code

This patch is the common base for my WIP series for ranges discards and to
remove discard_zeroes_data in favor of always using REQ_OP_WRITE_ZEROES,
so it would be good to get it in quickly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Additionally, rename srp_wait_for_queuecommand() into
scsi_wait_for_queuecommand() and add a comment about the queuecommand()
call from scsi_send_eh_cmnd().

Note: this patch changes scsi_internal_device_block from a function that
did not sleep into a function that may sleep. This is fine for all
callers of this function:

* scsi_internal_device_block() is called from the mpt3sas device while
  that driver holds the ioc->dm_cmds.mutex. This means that the mpt3sas
  driver calls this function from thread context.
* scsi_target_block() is called by __iscsi_block_session() from
  kernel thread context and with IRQs enabled.
* The SRP transport code also calls scsi_target_block() from kernel
  thread context while sleeping is allowed.
* The snic driver also calls scsi_target_block() from a context from
  which sleeping is allowed. The scsi_target_block() call namely occurs
  immediately after a scsi_flush_work() call.

[mkp: s/shost/sdev/]
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Cc: James Bottomley <jejb@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Doug Ledford <dledford@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Let's not depend on any of the BLK_MQ_RQ_QUEUE_* constants having
specific values. No functional change.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Just hand through the blk-mq map_queues method in the host template.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Most blk_mq_requeue_request() and blk_mq_add_to_requeue_list() calls
are followed by kicking the requeue list. Hence add an argument to
these two functions that allows to kick the requeue list. This was
proposed by Christoph Hellwig.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Since blk_mq_requeue_work() starts stopped queues and since
execution of this function can be scheduled after a queue has
been stopped it is not possible to stop queues without using
an additional state variable to track whether or not the queue
has been stopped. Hence modify blk_mq_requeue_work() such that it
does not start stopped queues. My conclusion after a review of
the blk_mq_stop_hw_queues() and blk_mq_{delay_,}kick_requeue_list()
callers is as follows:
* In the dm driver starting and stopping queues should only happen
  if __dm_suspend() or __dm_resume() is called and not if the
  requeue list is processed.
* In the SCSI core queue stopping and starting should only be
  performed by the scsi_internal_device_block() and
  scsi_internal_device_unblock() functions but not by any other
  function. Although the blk_mq_stop_hw_queue() call in
  scsi_queue_rq() may help to reduce CPU load if a LLD queue is
  full, figuring out whether or not a queue should be restarted
  when requeueing a command would require to introduce additional
  locking in scsi_mq_requeue_cmd() to avoid a race with
  scsi_internal_device_block(). Avoid this complexity by removing
  the blk_mq_stop_hw_queue() call from scsi_queue_rq().
* In the NVMe core only the functions that call
  blk_mq_start_stopped_hw_queues() explicitly should start stopped
  queues.
* A blk_mq_start_stopped_hwqueues() call must be added in the
  xen-blkfront driver in its blkif_recover() function.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: James Bottomley <jejb@linux.vnet.ibm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

A lot of the REQ_* flags are only used on struct requests, and only of
use to the block layer and a few drivers that dig into struct request
internals.

This patch adds a new req_flags_t rq_flags field to struct request for
them, and thus dramatically shrinks the number of common requests.  It
also removes the unfortunate situation where we have to fit the fields
from the same enum into 32 bits for struct bio and 64 bits for
struct request.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NShaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

All drivers use the default, so provide an inline version of it.  If we
ever need other queue mapping we can add an optional method back,
although supporting will also require major changes to the queue setup
code.

This provides better code generation, and better debugability as well.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

When SCSI was written, all commands coming from the filesystem
(REQ_TYPE_FS commands) had data.  This meant that our signal for needing
to complete the command was the number of bytes completed being equal to
the number of bytes in the request.  Unfortunately, with the advent of
flush barriers, we can now get zero length REQ_TYPE_FS commands, which
confuse this logic because they satisfy the condition every time.  This
means they never get retried even for retryable conditions, like UNIT
ATTENTION because we complete them early assuming they're done.  Fix
this by special casing the early completion condition to recognise zero
length commands with errors and let them drop through to the retry code.

Cc: stable@vger.kernel.org
Reported-by: NSebastian Parschauer <s.parschauer@gmx.de>
Signed-off-by: NJames E.J. Bottomley <jejb@linux.vnet.ibm.com>
Tested-by: NJack Wang <jinpu.wang@profitbricks.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Some arrays / HBAs will only present T10 vendor IDs, so we should be
decoding them, too.

[mkp: Fixed T10 spelling]
Suggested-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NHannes Reinecke <hare@suse.com>
Tested-by: NPaul Mackerras <paulus@ozlabs.org>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Now it's ready to move the mempool based SG chained allocator code from
SCSI driver to lib/sg_pool.c, which will be compiled only based on a Kconfig
symbol CONFIG_SG_POOL.

SCSI selects CONFIG_SG_POOL.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lin <ming.l@ssi.samsung.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Rename SCSI_MAX_SG_SEGMENTS to SG_CHUNK_SIZE, which means the amount
we fit into a single scatterlist chunk.

Rename SCSI_MAX_SG_CHAIN_SEGMENTS to SG_MAX_SEGMENTS.

Will move these 2 generic definitions to scatterlist.h later.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Acked-by: Bart Van Assche <bart.vanassche@sandisk.com> (for ib_srp changes)
Signed-off-by: NMing Lin <ming.l@ssi.samsung.com>
Acked-by: NTejun Heo <tj@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Rename SCSI specific struct and functions to more genenic names.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lin <ming.l@ssi.samsung.com>
Reviewed-by: NSagi Grimberg <sgi@grimberg.me>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Parameter "bool mq" is block driver specific.
Change it to "first_chunk" to make it more generic.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lin <ming.l@ssi.samsung.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Replace parameter "struct scsi_data_buffer" with "struct sg_table" in
SG alloc/free functions to make them generic.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lin <ming.l@ssi.samsung.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

When called scsi_prep_fn return BLKPREP_INVALID, we should use the same
code with BLKPREP_KILL in scsi_prep_return.
Signed-off-by: NYiwen Jiang <jiangyiwen@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

If a device needs to be rescanned the device_handler might need
to be rechecked, too.
So add a 'rescan' callback to the device handler and call it
upon scsi_rescan_device(). The rescan callback will be invoked
from the Unit Attention handling of ASC/ASCQ 3F 03
(INQUIRY DATA HAS CHANGED).
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Implement scsi_vpd_tpg_id() to extract the target
port group id and the relative port id from
SCSI VPD page 0x83.
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Add a function scsi_vpd_lun_id() to return a unique device
identifcation based on the designation descriptors of
VPD page 0x83.

As devices might implement several descriptors the order
of preference is:
- NAA IEE Registered Extended
- EUI-64 based 16-byte
- EUI-64 based 12-byte
- NAA IEEE Registered
- NAA IEEE Extended
A SCSI name string descriptor is preferred to all of them
if the identification is longer than 16 bytes.

The returned unique device identification will be formatted
as a SCSI Name string to avoid clashes between different
designator types.

[mkp: Fixed up kernel doc comment from Johannes]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NEwan Milne <emilne@redhat.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

__GFP_WAIT was used to signal that the caller was in atomic context and
could not sleep.  Now it is possible to distinguish between true atomic
context and callers that are not willing to sleep.  The latter should
clear __GFP_DIRECT_RECLAIM so kswapd will still wake.  As clearing
__GFP_WAIT behaves differently, there is a risk that people will clear the
wrong flags.  This patch renames __GFP_WAIT to __GFP_RECLAIM to clearly
indicate what it does -- setting it allows all reclaim activity, clearing
them prevents it.

[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NMel Gorman <mgorman@techsingularity.net>
Acked-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

blk_mq_complete_request may be a no-op if the request has already
been completed by others means (e.g. a timeout or cancellation), but
currently drivers have to set rq->errors before calling
blk_mq_complete_request, which might leave us with the wrong error value.

Add an error parameter to blk_mq_complete_request so that we can
defer setting rq->errors until we known we won the race to complete the
request.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Add a ->handler and a ->handler_data field to struct scsi_device and kill
this indirection.  Also move struct scsi_device_handler to scsi_dh.h so that
changes to it don't require rebuilding every SCSI LLDD.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Log the ALUA state change unit attention correctly with
the message log and emit an event to allow user-space
tools to react to it.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NEwan D. Milne <emilne@redhat.com>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

The 'sd' driver is calling scsi_mode_sense() to figure out
internal details. But scsi_mode_sense() never checks for
any pending unit attentions, so we're getting annoying error
messages like:

MODE SENSE: unimplemented page/subpage: 0x00/0x00

and a possible wrong decision for device cache handling.
Reviewed-by: NEwan Milne <emilne@redhat.com>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Fix a memory leak with scsi-mq triggered by commands with large data
transfer length.

__sg_alloc_table() sets both table->nents and table->orig_nents to the
same value.  When the scatterlist is DMA-mapped, table->nents is
overwritten with the (possibly smaller) size of the DMA-mapped
scatterlist, while table->orig_nents retains the original size of the
allocated scatterlist.  scsi_free_sgtable() should therefore check
orig_nents instead of nents, and all code that initializes sdb->table
without calling __sg_alloc_table() should set both nents and orig_nents.

Fixes: d285203c ("scsi: add support for a blk-mq based I/O path.")
Cc: <stable@vger.kernel.org> # 3.17+
Signed-off-by: NTony Battersby <tonyb@cybernetics.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NEwan D. Milne <emilne@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

SCSI transport drivers and SCSI LLDs block a SCSI device if the
transport layer is not operational. This means that in this state
no requests should be processed, even if the REQ_PREEMPT flag has
been set. This patch avoids that a rescan shortly after a cable
pull sporadically triggers the following kernel oops:

BUG: unable to handle kernel paging request at ffffc9001a6bc084
IP: [<ffffffffa04e08f2>] mlx4_ib_post_send+0xd2/0xb30 [mlx4_ib]
Process rescan-scsi-bus (pid: 9241, threadinfo ffff88053484a000, task ffff880534aae100)
Call Trace:
 [<ffffffffa0718135>] srp_post_send+0x65/0x70 [ib_srp]
 [<ffffffffa071b9df>] srp_queuecommand+0x1cf/0x3e0 [ib_srp]
 [<ffffffffa0001ff1>] scsi_dispatch_cmd+0x101/0x280 [scsi_mod]
 [<ffffffffa0009ad1>] scsi_request_fn+0x411/0x4d0 [scsi_mod]
 [<ffffffff81223b37>] __blk_run_queue+0x27/0x30
 [<ffffffff8122a8d2>] blk_execute_rq_nowait+0x82/0x110
 [<ffffffff8122a9c2>] blk_execute_rq+0x62/0xf0
 [<ffffffffa000b0e8>] scsi_execute+0xe8/0x190 [scsi_mod]
 [<ffffffffa000b2f3>] scsi_execute_req+0xa3/0x130 [scsi_mod]
 [<ffffffffa000c1aa>] scsi_probe_lun+0x17a/0x450 [scsi_mod]
 [<ffffffffa000ce86>] scsi_probe_and_add_lun+0x156/0x480 [scsi_mod]
 [<ffffffffa000dc2f>] __scsi_scan_target+0xdf/0x1f0 [scsi_mod]
 [<ffffffffa000dfa3>] scsi_scan_host_selected+0x183/0x1c0 [scsi_mod]
 [<ffffffffa000edfb>] scsi_scan+0xdb/0xe0 [scsi_mod]
 [<ffffffffa000ee13>] store_scan+0x13/0x20 [scsi_mod]
 [<ffffffff811c8d9b>] sysfs_write_file+0xcb/0x160
 [<ffffffff811589de>] vfs_write+0xce/0x140
 [<ffffffff81158b53>] sys_write+0x53/0xa0
 [<ffffffff81464592>] system_call_fastpath+0x16/0x1b
 [<00007f611c9d9300>] 0x7f611c9d92ff
Reported-by: NMax Gurtuvoy <maxg@mellanox.com>
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

This is the blk-mq part to support tag allocation policy. The default
allocation policy isn't changed (though it's not a strict FIFO). The new
policy is round-robin for libata. But it's a try-best implementation. If
multiple tasks are competing, the tags returned will be mixed (which is
unavoidable even with !mq, as requests from different tasks can be
mixed in queue)

Cc: Jens Axboe <axboe@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This can happen if a multipathed device uses DIX and another path is
added via an adapter that does not support it.  Multipath should not
allow this path to be added, but we should not depend upon that to avoid
crashing.
Signed-off-by: NEwan D. Milne <emilne@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The blk-mq ->queue_rq method is always called from process context,
but might have preemption disabled.  This means we still always
have to use GFP_ATOMIC for memory allocations, and thus need to
revert part of commit 3c356bde ("scsi: stop passing a gfp_mask
argument down the command setup path").
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Tested-by: NAlexei Starovoitov <alexei.starovoitov@gmail.com>

This fixes random memory corruption triggered when all three of the
following are true:

* scsi-mq enabled
* T10 Protection Information (DIF) enabled
* SCSI host with sg_tablesize > SCSI_MAX_SG_SEGMENTS (128)

The symptoms of this bug are unpredictable memory corruption, BUG()s,
oopses, lockups, etc., any of which may appear to be completely
unrelated to the root cause.

Cc: <stable@vger.kernel.org> # 3.17.x, 3.18.x
Signed-off-by: NTony Battersby <tonyb@cybernetics.com>
Reviewed-by: NNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

scsi_lib.c is where the rest of the I/O submission path lives, so move
scsi_dispatch_cmd there and mark it static.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NHannes Reinecke <hare@suse.de>

There is no reason for ULDs to pass in a flag on how to allocate the S/G
lists.  While we don't need GFP_ATOMIC for the blk-mq case because we
don't hold locks, that decision can be made way down the chain without
having to pass a pointless gfp_mask argument.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NHannes Reinecke <hare@suse.de>

There's only one caller left, so inline it and reduce the blk-mq vs !blk-mq
diff a litte bit.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NHannes Reinecke <hare@suse.de>

Currently scsi piggy backs on the block layer to define the concept
of a tagged command.  But we want to be able to have block-level host-wide
tags assigned even for untagged commands like the initial INQUIRY, so add
a new SCSI-level flag for commands that are tagged at the scsi level, so
that even commands without that set can have tags assigned to them.  Note
that this alredy is the case for the blk-mq code path, and this just lets
the old path catch up with it.

We also set this flag based upon sdev->simple_tags instead of the block
queue flag, so that it is entirely independent of the block layer tagging,
and thus always correct even if a driver doesn't use block level tagging
yet.

Also remove the old blk_rq_tagged; it was only used by SCSI drivers, and
removing it forces them to look for the proper replacement.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>