Schedulers need to be informed when a hardware queue is added or removed
at runtime so they can allocate/free per-hardware queue data. So,
replace the blk_mq_sched_init_hctx_data() helper, which only makes sense
at init time, with .init_hctx() and .exit_hctx() hooks.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

We've added a considerable amount of fixes for stalls and issues
with the blk-mq scheduling in the 4.11 series since forking
off the for-4.12/block branch. We need to do improvements on
top of that for 4.12, so pull in the previous fixes to make
our lives easier going forward.
Signed-off-by: NJens Axboe <axboe@fb.com>

To improve scalability, if hardware queues are shared, restart
a single hardware queue in round-robin fashion. Rename
blk_mq_sched_restart_queues() to reflect the new semantics.
Remove blk_mq_sched_mark_restart_queue() because this function
has no callers. Remove flag QUEUE_FLAG_RESTART because this
patch removes the code that uses this flag.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

While running the srp-test software I noticed that request
processing stalls sporadically at the beginning of a test, namely
when mkfs is run against a dm-mpath device. Every time when that
happened the following command was sufficient to resume request
processing:

    echo run >/sys/kernel/debug/block/dm-0/state

This patch avoids that such request processing stalls occur. The
test I ran is as follows:

    while srp-test/run_tests -d -r 30 -t 02-mq; do :; done
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Signed-off-by: NJens Axboe <axboe@fb.com>

If a .queue_rq() function returns BLK_MQ_RQ_QUEUE_BUSY then the block
driver that implements that function is responsible for rerunning the
hardware queue once requests can be queued again successfully.

commit 52d7f1b5 ("blk-mq: Avoid that requeueing starts stopped
queues") removed the blk_mq_stop_hw_queue() call from scsi_queue_rq()
for the BLK_MQ_RQ_QUEUE_BUSY case. Hence change all calls to functions
that are intended to rerun a busy queue such that these examine all
hardware queues instead of only stopped queues.

Since no other functions than scsi_internal_device_block() and
scsi_internal_device_unblock() should ever stop or restart a SCSI
queue, change the blk_mq_delay_queue() call into a
blk_mq_delay_run_hw_queue() call.

Fixes: commit 52d7f1b5 ("blk-mq: Avoid that requeueing starts stopped queues")
Fixes: commit 7e79dadc ("blk-mq: stop hardware queue in blk_mq_delay_queue()")
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Long Li <longli@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Introduce a function that runs a hardware queue unconditionally
after a delay. Note: there is already a function that stops and
restarts a hardware queue after a delay, namely blk_mq_delay_queue().

This function will be used in the next patch in this series.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Long Li <longli@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Currently only dm and md/raid5 bios trigger
trace_block_bio_complete().  Now that we have bio_chain() and
bio_inc_remaining(), it is not possible, in general, for a driver to
know when the bio is really complete.  Only bio_endio() knows that.

So move the trace_block_bio_complete() call to bio_endio().

Now trace_block_bio_complete() pairs with trace_block_bio_queue().
Any bio for which a 'queue' event is traced, will subsequently
generate a 'complete' event.

There are a few cases where completion tracing is not wanted.
1/ If blk_update_request() has already generated a completion
   trace event at the 'request' level, there is no point generating
   one at the bio level too.  In this case the bi_sector and bi_size
   will have changed, so the bio level event would be wrong

2/ If the bio hasn't actually been queued yet, but is being aborted
   early, then a trace event could be confusing.  Some filesystems
   call bio_endio() but do not want tracing.

3/ The bio_integrity code interposes itself by replacing bi_end_io,
   then restoring it and calling bio_endio() again.  This would produce
   two identical trace events if left like that.

To handle these, we introduce a flag BIO_TRACE_COMPLETION and only
produce the trace event when this is set.
We address point 1 above by clearing the flag in blk_update_request().
We address point 2 above by only setting the flag when
generic_make_request() is called.
We address point 3 above by clearing the flag after generating a
completion event.

When bio_split() is used on a bio, particularly in blk_queue_split(),
there is an extra complication.  A new bio is split off the front, and
may be handle directly without going through generic_make_request().
The old bio, which has been advanced, is passed to
generic_make_request(), so it will trigger a trace event a second
time.
Probably the best result when a split happens is to see a single
'queue' event for the whole bio, then multiple 'complete' events - one
for each component.  To achieve this was can:
- copy the BIO_TRACE_COMPLETION flag to the new bio in bio_split()
- avoid generating a 'queue' event if BIO_TRACE_COMPLETION is already set.
This way, the split-off bio won't create a queue event, the original
won't either even if it re-submitted to generic_make_request(),
but both will produce completion events, each for their own range.

So if generic_make_request() is called (which generates a QUEUED
event), then bi_endio() will create a single COMPLETE event for each
range that the bio is split into, unless the driver has explicitly
requested it not to.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

The comment for the 'flags' field of 'bio' mentions
"command" which is no longer stored there, and doesn't
mention the bvec pool number, which is.

BIO_RESET_BITS is set in such a way that it would need to be
updated if new bits were added, which is easy to miss.

BVEC_POOL_BITS is larger than needed.  The BVEC_POOL_IDX()
ranges from 0 to 6, so 3 bits are sufficient.

This patch make improvements in each of these areas.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

blk_mq_update_nr_hw_queues() used to remap hardware queues, which is the
behavior that drivers expect. However, commit 4e68a011 changed
blk_mq_queue_reinit() to not remap queues for the case of CPU
hotplugging, inadvertently making blk_mq_update_nr_hw_queues() not remap
queues as well. This breaks, for example, NBD's multi-connection mode,
leaving the added hardware queues unused. Fix it by making
blk_mq_update_nr_hw_queues() explicitly remap the queues.

Fixes: 4e68a011 ("blk-mq: don't redistribute hardware queues on a CPU hotplug event")
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

In elevator_switch(), if blk_mq_init_sched() fails, we attempt to fall
back to the original scheduler. However, at this point, we've already
torn down the original scheduler's tags, so this causes a crash. Doing
the fallback like the legacy elevator path is much harder for mq, so fix
it by just falling back to none, instead.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

If a new hardware queue is added at runtime, we don't allocate scheduler
tags for it, leading to a crash. This hooks up the scheduler framework
to blk_mq_{init,exit}_hctx() to make sure everything gets properly
initialized/freed.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Preparation cleanup for the next couple of fixes, push
blk_mq_sched_setup() and e->ops.mq.init_sched() into a helper.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

While dispatching requests, if we fail to get a driver tag, we mark the
hardware queue as waiting for a tag and put the requests on a
hctx->dispatch list to be run later when a driver tag is freed. However,
blk_mq_dispatch_rq_list() may dispatch requests from multiple hardware
queues if using a single-queue scheduler with a multiqueue device. If
blk_mq_get_driver_tag() fails, it doesn't update the hardware queue we
are processing. This means we end up using the hardware queue of the
previous request, which may or may not be the same as that of the
current request. If it isn't, the wrong hardware queue will end up
waiting for a tag, and the requests will be on the wrong dispatch list,
leading to a hang.

The fix is twofold:

1. Make sure we save which hardware queue we were trying to get a
   request for in blk_mq_get_driver_tag() regardless of whether it
   succeeds or not.
2. Make blk_mq_dispatch_rq_list() take a request_queue instead of a
   blk_mq_hw_queue to make it clear that it must handle multiple
   hardware queues, since I've already messed this up on a couple of
   occasions.

This didn't appear in testing with nvme and mq-deadline because nvme has
more driver tags than the default number of scheduler tags. However,
with the blk_mq_update_nr_hw_queues() fix, it showed up with nbd.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

After commit 64c7f1d1, we went from 1 to 2 holes in my
test setup. If we move the timeout field a bit, we remove
both of those holes and shrink struct request by 8 bytes.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Instead of bloating the generic struct request with it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

The way NVMe uses this field is entirely different from the older
SCSI/BLOCK_PC usage, so move it into struct nvme_request.

Also reduce the size of the file to a unsigned char so that we leave
space for additional smaller fields that will appear soon.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Don't pass the status explicitly but derive it from the requeust,
and unwind the complex condition to be more readable.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

->retries is counting the number of times a command is resubmitted, and
be cleared on the first time we see the command.  We currently don't do
that for non-PCIe command, which is easily fixed by moving the setup
to common code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

This driver is for pre-IDE hardisk that are only found in PC from the
stoneage of personal computing, and which we don't support elsewhere
in the kernel these days.

It's also been marked broken forever.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

The block layer core sets blk_mq_queue_data.list but no block
drivers read that member. Hence remove it and also the code that
is used to set this member.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Writeback throttling does not play well with CFQ since that also tries
to throttle async writes. As a result async writeback can get starved in
presence of readers. As an example take a benchmark simulating
postgreSQL database running over a standard rotating SATA drive. There
are 16 processes doing random reads from a huge file (2*machine memory),
1 process doing random writes to the huge file and calling fsync once
per 50000 writes and 1 process doing sequential 8k writes to a
relatively small file wrapping around at the end of the file and calling
fsync every 5 writes. Under this load read latency easily exceeds the
target latency of 75 ms (just because there are so many reads happening
against a relatively slow disk) and thus writeback is throttled to a
point where only 1 write request is allowed at a time. Blktrace data
then looks like:

  8,0    1        0     8.347751764     0  m   N cfq workload slice:40000000
  8,0    1        0     8.347755256     0  m   N cfq293A  / set_active wl_class: 0 wl_type:0
  8,0    1        0     8.347784100     0  m   N cfq293A  / Not idling.  st->count:1
  8,0    1     3814     8.347763916  5839 UT   N [kworker/u9:2] 1
  8,0    0        0     8.347777605     0  m   N cfq293A  / Not idling.  st->count:1
  8,0    1        0     8.347784100     0  m   N cfq293A  / Not idling.  st->count:1
  8,0    3     1596     8.354364057     0  C   R 156109528 + 8 (6906954) [0]
  8,0    3        0     8.354383193     0  m   N cfq6196SN / complete rqnoidle 0
  8,0    3        0     8.354386476     0  m   N cfq schedule dispatch
  8,0    3        0     8.354399397     0  m   N cfq293A  / Not idling.  st->count:1
  8,0    3        0     8.354404705     0  m   N cfq293A  / dispatch_insert
  8,0    3        0     8.354409454     0  m   N cfq293A  / dispatched a request
  8,0    3        0     8.354412527     0  m   N cfq293A  / activate rq, drv=1
  8,0    3     1597     8.354414692     0  D   W 145961400 + 24 (6718452) [swapper/0]
  8,0    3        0     8.354484184     0  m   N cfq293A  / Not idling.  st->count:1
  8,0    3        0     8.354487536     0  m   N cfq293A  / slice expired t=0
  8,0    3        0     8.354498013     0  m   N / served: vt=5888102466265088 min_vt=5888074869387264
  8,0    3        0     8.354502692     0  m   N cfq293A  / sl_used=6737519 disp=1 charge=6737519 iops=0 sect=24
  8,0    3        0     8.354505695     0  m   N cfq293A  / del_from_rr
...
  8,0    0     1810     8.354728768     0  C   W 145961400 + 24 (314076) [0]
  8,0    0        0     8.354746927     0  m   N cfq293A  / complete rqnoidle 0
...
  8,0    1     3829     8.389886102  5839  G   W 145962968 + 24 [kworker/u9:2]
  8,0    1     3830     8.389888127  5839  P   N [kworker/u9:2]
  8,0    1     3831     8.389908102  5839  A   W 145978336 + 24 <- (8,4) 44000
  8,0    1     3832     8.389910477  5839  Q   W 145978336 + 24 [kworker/u9:2]
  8,0    1     3833     8.389914248  5839  I   W 145962968 + 24 (28146) [kworker/u9:2]
  8,0    1        0     8.389919137     0  m   N cfq293A  / insert_request
  8,0    1        0     8.389924305     0  m   N cfq293A  / add_to_rr
  8,0    1     3834     8.389933175  5839 UT   N [kworker/u9:2] 1
...
  8,0    0        0     9.455290997     0  m   N cfq workload slice:40000000
  8,0    0        0     9.455294769     0  m   N cfq293A  / set_active wl_class:0 wl_type:0
  8,0    0        0     9.455303499     0  m   N cfq293A  / fifo=ffff880003166090
  8,0    0        0     9.455306851     0  m   N cfq293A  / dispatch_insert
  8,0    0        0     9.455311251     0  m   N cfq293A  / dispatched a request
  8,0    0        0     9.455314324     0  m   N cfq293A  / activate rq, drv=1
  8,0    0     2043     9.455316210  6204  D   W 145962968 + 24 (1065401962) [pgioperf]
  8,0    0        0     9.455392407     0  m   N cfq293A  / Not idling.  st->count:1
  8,0    0        0     9.455395969     0  m   N cfq293A  / slice expired t=0
  8,0    0        0     9.455404210     0  m   N / served: vt=5888958194597888 min_vt=5888941810597888
  8,0    0        0     9.455410077     0  m   N cfq293A  / sl_used=4000000 disp=1 charge=4000000 iops=0 sect=24
  8,0    0        0     9.455416851     0  m   N cfq293A  / del_from_rr
...
  8,0    0     2045     9.455648515     0  C   W 145962968 + 24 (332305) [0]
  8,0    0        0     9.455668350     0  m   N cfq293A  / complete rqnoidle 0
...
  8,0    1     4371     9.455710115  5839  G   W 145978336 + 24 [kworker/u9:2]
  8,0    1     4372     9.455712350  5839  P   N [kworker/u9:2]
  8,0    1     4373     9.455730159  5839  A   W 145986616 + 24 <- (8,4) 52280
  8,0    1     4374     9.455732674  5839  Q   W 145986616 + 24 [kworker/u9:2]
  8,0    1     4375     9.455737563  5839  I   W 145978336 + 24 (27448) [kworker/u9:2]
  8,0    1        0     9.455742871     0  m   N cfq293A  / insert_request
  8,0    1        0     9.455747550     0  m   N cfq293A  / add_to_rr
  8,0    1     4376     9.455756629  5839 UT   N [kworker/u9:2] 1

So we can see a Q event for a write request, then IO is blocked by
writeback throttling and G and I events for the request happen only once
other writeback IO is completed. Thus CFQ always sees only one write
request. When it sees it, it queues the async queue behind all the read
queues and the async queue gets scheduled after about one second. When
it is scheduled, that one request gets dispatched and async queue is
expired as it has no more requests to submit. Overall we submit about
one write request per second.

Although this scheduling is beneficial for read latency, writes are
heavily starved and this causes large delays all over the system (due to
processes blocking on page lock, transaction starts, etc.). When
writeback throttling is disabled, write throughput is about one fifth of
a read throughput which roughly matches readers/writers ratio and
overall the system stalls are much shorter.

Mixing writeback throttling logic with CFQ throttling logic is always a
recipe for surprises as CFQ assumes it sees the big part of the picture
which is not necessarily true when writeback throttling is blocking
requests. So disable writeback throttling logic by default when CFQ is
used as an IO scheduler.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

In 4.10 I introduced a patch that associates the ioc priority with
each request in the block layer. This work was done in the single queue
block layer code. This patch unifies ioc priority to request mapping across
the single/multi queue block layers.

I have tested this patch with the null block device driver with the following
parameters.

null_blk queue_mode=2 irqmode=0 use_per_node_hctx=1 nr_devices=1

I have not seen a performance regression with this patch and I would appreciate
any feedback or additional testing.

I have also verified that io priorities are passed to the device when using
the SQ and MQ path to a SATA HDD that supports io priorities.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAdam Manzanares <adam.manzanares@wdc.com>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This avoids duplicating the logic four times, and it also allows to keep
some helpers static in core.c or just opencode them.

Note that this loses printing the aborted status on completions in the
PCI driver as that uses a data structure not available any more.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

A requeue means we go through nvme_fc_start_fcp_op again and get
another controller reference.  To make sure the refcount doesn't
leak we also need to drop it for every completion that came from
the LLDD.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

This way our max retry limit holds as well.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

This way our max retry limit holds as well.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

This way our max retry limit holds as well.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

As Dan Carpenter pointed out: mixing 16-bit nvme status with 32-bit
error status from driver. Corrected comment on fcp request struct
status field, and converted done routine to explicitly set nvme status
codes for nvme status.
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Clear SG list to avoid double frees of payload page list
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

LS validations shouldn't have been independent checks.
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

nvmet_fc: Sync NVME LS reject reasons with spec
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Add check of status_code in ERSP_IU
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Update FC-NVME definitions to match FC-NVME r1.14 (16-020vB) plus
change voted in by 2/22 FC-NVME Adhoc (see HOSTID below).

Includes the following:
- Addition of "status_code" field to ERSP IU
- Addition of FC-NVME LS RJT reason_codes and reason_explanations
- CreateAssociation payload, HostID field shortened to 16 bytes
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Before scheduling a reconnect attempt, check
nr_reconnects against max_reconnects, if not
exhausted (or max_reconnects is not -1), schedule
a reconnect attempts, otherwise schedule ctrl
removal.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

When a host sense that its controller session is damaged,
it tries to re-establish it periodically (reconnect every
reconnect_delay). It may very well be that the controller
is gone and never coming back, in this case the host will
try to reconnect forever.

Add a ctrl_loss_tmo to bound the number of reconnect attempts
to a specific controller (default to a reasonable 10 minutes).
The timeout configuration is actually translated into number of
reconnect attempts and not a schedule on its own but rather
divided with reconnect_delay. This is useful to prevent
racing flows of remove and reconnect, and it doesn't really
matter if we remove slightly sooner than what the user requested.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

we already have it in opts.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

useful to validate that the we didn't mess up
the command_id.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

If nvmf_register_transport happened to fail
(it can't, but theoretically) we leak memory.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>