This patch does not change any functionality.
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

PSDT field section according to NVM_Express-1.3:
"This field specifies whether PRPs or SGLs are used for any data
transfer associated with the command. PRPs shall be used for all
Admin commands for NVMe over PCIe. SGLs shall be used for all Admin
and I/O commands for NVMe over Fabrics. This field shall be set to
01b for NVMe over Fabrics 1.0 implementations.
Suggested-by: NIdan Burstein <idanb@mellanox.com>
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <keith.busch@intel.com>

If multipathing is enabled, each NVMe subsystem creates a head
namespace (e.g., nvme0n1) and multiple private namespaces
(e.g., nvme0c0n1 and nvme0c1n1) in sysfs. When creating links for
private namespaces, links of head namespace are used, so the
namespace creation order must be followed (e.g., nvme0n1 ->
nvme0c1n1). If the order is not followed, links of sysfs will be
incomplete or kernel panic will occur.

The kernel panic was:
  kernel BUG at fs/sysfs/symlink.c:27!
  Call Trace:
    nvme_mpath_add_disk_links+0x5d/0x80 [nvme_core]
    nvme_validate_ns+0x5c2/0x850 [nvme_core]
    nvme_scan_work+0x1af/0x2d0 [nvme_core]

Correct order
Context A     Context B
nvme0n1
nvme0c0n1     nvme0c1n1

Incorrect order
Context A     Context B
              nvme0c1n1
nvme0n1
nvme0c0n1

The nvme_mpath_add_disk (for creating head namespace) is called
just before the nvme_mpath_add_disk_links (for creating private
namespaces). In nvme_mpath_add_disk, the first context acquires
the lock of subsystem and creates a head namespace, and other
contexts do nothing by checking GENHD_FL_UP of a head namespace
after waiting to acquire the lock. We verified the code with or
without multipathing using three vendors of dual-port NVMe SSDs.
Signed-off-by: NBaegjae Sung <baegjae@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <keith.busch@intel.com>

This patch fixes nvme queue cleanup if requesting an IRQ handler for
the queue's vector fails. It does this by resetting the cq_vector to
the uninitialized value of -1 so it is ignored for a controller reset.
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
[changelog updates, removed misc whitespace changes]
Signed-off-by: NKeith Busch <keith.busch@intel.com>

blk_rq_bytes does the wrong thing for special payloads like discards and
might cause the driver to not set up a SGL.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NKeith Busch <keith.busch@intel.com>

blk_rq_bytes does the wrong thing for special payloads like discards and
might cause the driver to not set up a SGL.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NKeith Busch <keith.busch@intel.com>

THIS_MODULE evaluates to NULL when used from code built into the kernel,
thus breaking built-in transport modules.  Remove the bogus check.

Fixes: 0de5cd36 ("nvme-fabrics: protect against module unload during create_ctrl")
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NKeith Busch <keith.busch@intel.com>

When reset_controller that is invoked by sysfs fails,
it enters an error flow which practically removes the
nvme ctrl entirely (similar to delete_ctrl flow). It
causes the system to hang, since a sysfs attribute cannot
be unregistered by one of its own methods.

This can be fixed by calling delete_ctrl as a work rather
than sequential code. In addition, it should give the ctrl
a chance to recover using reconnection mechanism (consistant
with FC reset_ctrl error flow). Also, while we're here, return
suitable errno in case the reset ended with non live ctrl.
Signed-off-by: NNitzan Carmi <nitzanc@mellanox.com>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

Execute discard command on block device that doesn't support it
should return success.
Returning internal error while using multi-path fails the path.
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NIsrael Rukshin <israelr@mellanox.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

We need to halt the controller immediately if we haven't completed
initialization as indicated by the new "connecting" state.

Fixes: ad70062c ("nvme-pci: introduce RECONNECTING state to mark initializing procedure")
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

The controller memory buffer is remapped into a kernel address on each
reset, but the driver was setting the submission queue base address
only on the very first queue creation. The remapped address is likely to
change after a reset, so accessing the old address will hit a kernel bug.

This patch fixes that by setting the queue's CMB base address each time
the queue is created.

Fixes: f63572df ("nvme: unmap CMB and remove sysfs file in reset path")
Reported-by: NChristian Black <christian.d.black@intel.com>
Cc: Jon Derrick <jonathan.derrick@intel.com>
Cc: <stable@vger.kernel.org> # 4.9+
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

nvme_update_formats will invoke nvme_ns_remove under namespaces_mutext.
The will cause deadlock because nvme_ns_remove will also require
the namespaces_mutext. Fix it by getting the ns entries which should
be removed under namespaces_mutext and invoke nvme_ns_remove out of
namespaces_mutext.
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

In nvme_keep_alive() we pass a request with a pointer to an NVMe command on
the stack into blk_execute_rq_nowait().  However, the block layer doesn't
guarantee that the request is fully queued before blk_execute_rq_nowait()
returns.  If not, and the request is queued after nvme_keep_alive() returns,
then we'll end up using stack memory that might have been overwritten to
form the NVMe command we pass to hardware.

Fix this by keeping a special command struct in the nvme_ctrl struct right
next to the delayed work struct used for keep-alives.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

There was some old cold that dealt with complete_rq being called
prior to the lldd returning the io completion. This is garbage code.
The complete_rq routine was being called after eh_timeouts were
called and it was due to eh_timeouts not being handled properly.
The timeouts were fixed in prior patches so that in general, a
timeout will initiate an abort and the reset timer restarted as
the abort operation will take care of completing things. Given the
reset timer restarted, the erroneous complete_rq calls were eliminated.

So remove the work that was synchronizing complete_rq with io
completion.
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

During reset handling, there is live io completing while the reset
is taking place. The reset path attempts to abort all outstanding io,
counting the number of ios that were reset. It then waits for those
ios to be reclaimed from the lldd before continuing.

The transport's logic on io state and flag setting was poor, allowing
ios to complete simultaneous to the abort request. The completed ios
were counted, but as the completion had already occurred, the
completion never reduced the count. As the count never zeros, the
reset/delete never completes.

Tighten it up by unconditionally changing the op state to completed
when the io done handler is called.  The reset/abort path now changes
the op state to aborted, but the abort only continues if the op
state was live priviously. If complete, the abort is backed out.
Thus proper counting of io aborts and their completions is working
again.

Also removed the TERMIO state on the op as it's redundant with the
op's aborted state.
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

This patch checks the discard range array bounds before setting it in
case the driver gets a badly formed request.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

There is no logical reason to move from live state to connecting
state. In case of initial connection establishment, the transition
should be NVME_CTRL_NEW --> NVME_CTRL_CONNECTING --> NVME_CTRL_LIVE.
In case of error recovery or reset, the transition should be
NVME_CTRL_LIVE --> NVME_CTRL_RESETTING --> NVME_CTRL_CONNECTING -->
NVME_CTRL_LIVE.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

In order to avoid concurrent error recovery during initialization
process (allowed by the NVME_CTRL_NEW --> NVME_CTRL_RESETTING transition)
we must mark the ctrl as CONNECTING before initial connection
establisment.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

In pci transport, this state is used to mark the initialization
process. This should be also used in other transports as well.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

This status is returned from driver to block layer if device related
resource is unavailable, but driver can guarantee that IO dispatch
will be triggered in future when the resource is available.

Convert some drivers to return BLK_STS_DEV_RESOURCE.  Also, if driver
returns BLK_STS_RESOURCE and SCHED_RESTART is set, rerun queue after
a delay (BLK_MQ_DELAY_QUEUE) to avoid IO stalls.  BLK_MQ_DELAY_QUEUE is
3 ms because both scsi-mq and nvmefc are using that magic value.

If a driver can make sure there is in-flight IO, it is safe to return
BLK_STS_DEV_RESOURCE because:

1) If all in-flight IOs complete before examining SCHED_RESTART in
blk_mq_dispatch_rq_list(), SCHED_RESTART must be cleared, so queue
is run immediately in this case by blk_mq_dispatch_rq_list();

2) if there is any in-flight IO after/when examining SCHED_RESTART
in blk_mq_dispatch_rq_list():
- if SCHED_RESTART isn't set, queue is run immediately as handled in 1)
- otherwise, this request will be dispatched after any in-flight IO is
  completed via blk_mq_sched_restart()

3) if SCHED_RESTART is set concurently in context because of
BLK_STS_RESOURCE, blk_mq_delay_run_hw_queue() will cover the above two
cases and make sure IO hang can be avoided.

One invariant is that queue will be rerun if SCHED_RESTART is set.
Suggested-by: NJens Axboe <axboe@kernel.dk>
Tested-by: NLaurence Oberman <loberman@redhat.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Add a tracepoint in nvme_complete_rq() for completions of NVMe commands. An
expmale output of the trace-point is as follows:

<idle>-0     [001] d.h.     3.505266: nvme_complete_rq: cmdid=989, qid=1, res=0, retries=0, flags=0x0, status=0
Signed-off-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Add tracepoints for nvme_setup_cmd() for tracing admin and/or nvm commands.

Examples of the two tracepoints are as follows for trace_nvme_setup_admin_cmd():
kworker/u8:0-5     [003] ....     2.998792: nvme_setup_admin_cmd: cmdid=14, flags=0x0, meta=0x0, cmd=(nvme_admin_create_cq cqid=1, qsize=1023, cq_flags=0x3, irq_vector=0)

and trace_nvme_setup_nvm_cmd():
dd-205   [001] ....     3.503929: nvme_setup_nvm_cmd: qid=1, nsid=1, cmdid=989, flags=0x0, meta=0x0, cmd=(nvme_cmd_read slba=4096, len=2047, ctrl=0x0, dsmgmt=0, reftag=0)
Signed-off-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

After Sagi's commit (nvme-rdma: fix concurrent reset and reconnect),
both nvme-fc/rdma have following pattern:
RESETTING    - quiesce blk-mq queues, teardown and delete queues/
               connections, clear out outstanding IO requests...
RECONNECTING - establish new queues/connections and some other
               initializing things.
Introduce RECONNECTING to nvme-pci transport to do the same mark.
Then we get a coherent state definition among nvme pci/rdma/fc
transports.
Suggested-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NReviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Commit df351ef7 ("nvme-fabrics: fix memory leak when parsing host ID
option") fixed the leak of 'p' but in case uuid_parse() fails the memory
is freed before the error print that is using it.

Free it after printing eventual errors.
Signed-off-by: NJohannes Thumshirn <jthumshirn@suse.de>
Fixes: df351ef7 ("nvme-fabrics: fix memory leak when parsing host ID option")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The driver had been abusing the cq_vector state to know if new submissions
were safe, but that was before we could quiesce blk-mq. If the controller
happens to get an interrupt through while we're suspending those queues,
'no irq handler' warnings may occur.

This patch will disable the interrupts only after the queues are deleted.
Reported-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Tested-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The queue count says the highest queue that's been allocated, so don't
reallocate a queue lower than that.

Fixes: 147b27e4 ("nvme-pci: allocate device queues storage space at probe")
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Some iommu implementations can merge physically and/or virtually
contiguous segments inside sg_map_dma.  The NVMe SGL support does not take
this into account and will warn because of falling off a loop.  Pass the
number of mapped segments to nvme_pci_setup_sgls so that the SGL setup
can take the number of mapped segments into account.
Reported-by: NFangjian (Turing) <f.fangjian@huawei.com>
Fixes: a7a7cbe3 ("nvme-pci: add SGL support")
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@rimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The driver needs to verify there is a payload with a command before
seeing if it should use SGLs to map it.

Fixes: 955b1b5a ("nvme-pci: move use_sgl initialization to nvme_init_iod()")
Reported-by: NPaul Menzel <pmenzel+linux-nvme@molgen.mpg.de>
Reviewed-by: NPaul Menzel <pmenzel+linux-nvme@molgen.mpg.de>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Define the bit positions instead of macros using the magic values,
and move the expanded helpers to calculate the size and size unit into
the implementation C file.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>

Refactor the call to nvme_map_cmb, and change the conditions for probing
for the CMB.  First remove the version check as NVMe TPs always apply
to earlier versions of the spec as well.  Second check for the whole CMBSZ
register for support of the CMB feature instead of just the size field
inside of it to simplify the code a bit.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>

When connectivity is lost to a device, the association is terminated
and the blk-mq queues are quiesced/stopped. When connectivity is
re-established, they are resumed.

If connectivity is lost for a sufficient amount of time that the
controller is then deleted, the delete path starts tearing down queues,
and eventually calling nvme_ns_remove(). It appears that pending
commands may cause blk_cleanup_queue() to never complete and the
teardown stalls.

Correct by starting the ns queues after transitioning to a DELETING
state, allowing pending commands to be flushed with io failures. Thus
the delete path is clear when reached.
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

When connectivity is lost to a device, the association is terminated
and the blk-mq queues are quiesced/stopped. When connectivity is
re-established, they are resumed.

If an admin command is received while connectivity is list, the ioctl
queues the command on the admin_q and the command stalls (the thread
issuing the ioctl hangs/waits). if the connectivity is lost long
enough such that the controller is then deleted, the delete code
makes its calls to initiate the delete, which then expects the core
layer to call the transport when all references are removed and the
controller can be freed.  Unfortunately, nothing in this path dequeued
the admin command, so a reference sits outstanding and things stop,
hanging the delete indefinitely.

Correct by unquiescing the admin queue in the delete association. This
means any admin command (which should only be from an ioctl) issued
after connectivity is lost will detect the controller is in a
reconnecting state and will (fast) fail the command. Thus, a pending
reference can no longer be created.  Once connectivity is re-established,
a new ioctl/admin command would see proper device state and function again.
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

nvmet_req_init looked up a namespace and took a reference on it (unless it
failed prior to that). If the request is uninitialized (in error cases) we
need to remove that reference in case it was taken, otherwise we leak
namespace reference when calling nvme_req_uninit.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We use match_strdup() to get a copy of the option string for host ID string, but
we just pass it to uuid_parse() and don't store the string pointer, so we need to
kfree() the string after parsing it.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

fix comment typos in nvme_create_io_queues() like below.
  _aount_ to _amount_
  _an_    to _can_
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We need to ensure that delete_work will be hosted on a different
workqueue than all the works we flush or cancel from it.
Otherwise we may hit a circular dependency warning [1].

Also, given that delete_work flushes reset_work, host reset_work
on nvme_reset_wq and delete_work on nvme_delete_wq. In addition,
fix the flushing in the individual drivers to flush nvme_delete_wq
when draining queued deletes.

[1]:
[  178.491942] =============================================
[  178.492718] [ INFO: possible recursive locking detected ]
[  178.493495] 4.9.0-rc4-c844263313a8-lb #3 Tainted: G           OE
[  178.494382] ---------------------------------------------
[  178.495160] kworker/5:1/135 is trying to acquire lock:
[  178.495894]  (
[  178.496120] "nvme-wq"
[  178.496471] ){++++.+}
[  178.496599] , at:
[  178.496921] [<ffffffffa70ac206>] flush_work+0x1a6/0x2d0
[  178.497670]
               but task is already holding lock:
[  178.498499]  (
[  178.498724] "nvme-wq"
[  178.499074] ){++++.+}
[  178.499202] , at:
[  178.499520] [<ffffffffa70ad6c2>] process_one_work+0x162/0x6a0
[  178.500343]
               other info that might help us debug this:
[  178.501269]  Possible unsafe locking scenario:

[  178.502113]        CPU0
[  178.502472]        ----
[  178.502829]   lock(
[  178.503115] "nvme-wq"
[  178.503467] );
[  178.503716]   lock(
[  178.504001] "nvme-wq"
[  178.504353] );
[  178.504601]
                *** DEADLOCK ***

[  178.505441]  May be due to missing lock nesting notation

[  178.506453] 2 locks held by kworker/5:1/135:
[  178.507068]  #0:
[  178.507330]  (
[  178.507598] "nvme-wq"
[  178.507726] ){++++.+}
[  178.508079] , at:
[  178.508173] [<ffffffffa70ad6c2>] process_one_work+0x162/0x6a0
[  178.509004]  #1:
[  178.509265]  (
[  178.509532] (&ctrl->delete_work)
[  178.509795] ){+.+.+.}
[  178.510145] , at:
[  178.510239] [<ffffffffa70ad6c2>] process_one_work+0x162/0x6a0
[  178.511070]
               stack backtrace:
:
[  178.511693] CPU: 5 PID: 135 Comm: kworker/5:1 Tainted: G           OE   4.9.0-rc4-c844263313a8-lb #3
[  178.512974] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-1ubuntu1 04/01/2014
[  178.514247] Workqueue: nvme-wq nvme_del_ctrl_work [nvme_tcp]
[  178.515071]  ffffc2668175bae0 ffffffffa7450823 ffffffffa88abd80 ffffffffa88abd80
[  178.516195]  ffffc2668175bb98 ffffffffa70eb012 ffffffffa8d8d90d ffff9c472e9ea700
[  178.517318]  ffff9c472e9ea700 ffff9c4700000000 ffff9c4700007200 ab83be61bec0d50e
[  178.518443] Call Trace:
[  178.518807]  [<ffffffffa7450823>] dump_stack+0x85/0xc2
[  178.519542]  [<ffffffffa70eb012>] __lock_acquire+0x17d2/0x18f0
[  178.520377]  [<ffffffffa75839a7>] ? serial8250_console_putchar+0x27/0x30
[  178.521330]  [<ffffffffa7583980>] ? wait_for_xmitr+0xa0/0xa0
[  178.522174]  [<ffffffffa70ac1eb>] ? flush_work+0x18b/0x2d0
[  178.522975]  [<ffffffffa70eb7cb>] lock_acquire+0x11b/0x220
[  178.523753]  [<ffffffffa70ac206>] ? flush_work+0x1a6/0x2d0
[  178.524535]  [<ffffffffa70ac229>] flush_work+0x1c9/0x2d0
[  178.525291]  [<ffffffffa70ac206>] ? flush_work+0x1a6/0x2d0
[  178.526077]  [<ffffffffa70a9cf0>] ? flush_workqueue_prep_pwqs+0x220/0x220
[  178.527040]  [<ffffffffa70ae7cf>] __cancel_work_timer+0x10f/0x1d0
[  178.527907]  [<ffffffffa70fecb9>] ? vprintk_default+0x29/0x40
[  178.528726]  [<ffffffffa71cb507>] ? printk+0x48/0x50
[  178.529434]  [<ffffffffa70ae8c3>] cancel_delayed_work_sync+0x13/0x20
[  178.530381]  [<ffffffffc042100b>] nvme_stop_ctrl+0x5b/0x70 [nvme_core]
[  178.531314]  [<ffffffffc0403dcc>] nvme_del_ctrl_work+0x2c/0x50 [nvme_tcp]
[  178.532271]  [<ffffffffa70ad741>] process_one_work+0x1e1/0x6a0
[  178.533101]  [<ffffffffa70ad6c2>] ? process_one_work+0x162/0x6a0
[  178.533954]  [<ffffffffa70adc4e>] worker_thread+0x4e/0x490
[  178.534735]  [<ffffffffa70adc00>] ? process_one_work+0x6a0/0x6a0
[  178.535588]  [<ffffffffa70adc00>] ? process_one_work+0x6a0/0x6a0
[  178.536441]  [<ffffffffa70b48cf>] kthread+0xff/0x120
[  178.537149]  [<ffffffffa70b47d0>] ? kthread_park+0x60/0x60
[  178.538094]  [<ffffffffa70b47d0>] ? kthread_park+0x60/0x60
[  178.538900]  [<ffffffffa78e332a>] ret_from_fork+0x2a/0x40
Signed-off-by: NRoy Shterman <roys@lightbitslabs.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

It may cause race by setting 'nvmeq' in nvme_init_request()
because .init_request is called inside switching io scheduler, which
may happen when the NVMe device is being resetted and its nvme queues
are being freed and created. We don't have any sync between the two
pathes.

This patch changes the nvmeq allocation to occur at probe time so
there is no way we can dereference it at init_request.

[   93.268391] kernel BUG at drivers/nvme/host/pci.c:408!
[   93.274146] invalid opcode: 0000 [#1] SMP
[   93.278618] Modules linked in: nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss
nfsv4 dns_resolver nfs lockd grace fscache sunrpc ipmi_ssif vfat fat
intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel
kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel iTCO_wdt
intel_cstate ipmi_si iTCO_vendor_support intel_uncore mxm_wmi mei_me
ipmi_devintf intel_rapl_perf pcspkr sg ipmi_msghandler lpc_ich dcdbas mei
shpchp acpi_power_meter wmi dm_multipath ip_tables xfs libcrc32c sd_mod
mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt
fb_sys_fops ttm drm ahci libahci nvme libata crc32c_intel nvme_core tg3
megaraid_sas ptp i2c_core pps_core dm_mirror dm_region_hash dm_log dm_mod
[   93.349071] CPU: 5 PID: 1842 Comm: sh Not tainted 4.15.0-rc2.ming+ #4
[   93.356256] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.5.5 08/16/2017
[   93.364801] task: 00000000fb8abf2a task.stack: 0000000028bd82d1
[   93.371408] RIP: 0010:nvme_init_request+0x36/0x40 [nvme]
[   93.377333] RSP: 0018:ffffc90002537ca8 EFLAGS: 00010246
[   93.383161] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000008
[   93.391122] RDX: 0000000000000000 RSI: ffff880276ae0000 RDI: ffff88047bae9008
[   93.399084] RBP: ffff88047bae9008 R08: ffff88047bae9008 R09: 0000000009dabc00
[   93.407045] R10: 0000000000000004 R11: 000000000000299c R12: ffff880186bc1f00
[   93.415007] R13: ffff880276ae0000 R14: 0000000000000000 R15: 0000000000000071
[   93.422969] FS:  00007f33cf288740(0000) GS:ffff88047ba80000(0000) knlGS:0000000000000000
[   93.431996] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   93.438407] CR2: 00007f33cf28e000 CR3: 000000047e5bb006 CR4: 00000000001606e0
[   93.446368] Call Trace:
[   93.449103]  blk_mq_alloc_rqs+0x231/0x2a0
[   93.453579]  blk_mq_sched_alloc_tags.isra.8+0x42/0x80
[   93.459214]  blk_mq_init_sched+0x7e/0x140
[   93.463687]  elevator_switch+0x5a/0x1f0
[   93.467966]  ? elevator_get.isra.17+0x52/0xc0
[   93.472826]  elv_iosched_store+0xde/0x150
[   93.477299]  queue_attr_store+0x4e/0x90
[   93.481580]  kernfs_fop_write+0xfa/0x180
[   93.485958]  __vfs_write+0x33/0x170
[   93.489851]  ? __inode_security_revalidate+0x4c/0x60
[   93.495390]  ? selinux_file_permission+0xda/0x130
[   93.500641]  ? _cond_resched+0x15/0x30
[   93.504815]  vfs_write+0xad/0x1a0
[   93.508512]  SyS_write+0x52/0xc0
[   93.512113]  do_syscall_64+0x61/0x1a0
[   93.516199]  entry_SYSCALL64_slow_path+0x25/0x25
[   93.521351] RIP: 0033:0x7f33ce96aab0
[   93.525337] RSP: 002b:00007ffe57570238 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[   93.533785] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f33ce96aab0
[   93.541746] RDX: 0000000000000006 RSI: 00007f33cf28e000 RDI: 0000000000000001
[   93.549707] RBP: 00007f33cf28e000 R08: 000000000000000a R09: 00007f33cf288740
[   93.557669] R10: 00007f33cf288740 R11: 0000000000000246 R12: 00007f33cec42400
[   93.565630] R13: 0000000000000006 R14: 0000000000000001 R15: 0000000000000000
[   93.573592] Code: 4c 8d 40 08 4c 39 c7 74 16 48 8b 00 48 8b 04 08 48 85 c0
74 16 48 89 86 78 01 00 00 31 c0 c3 8d 4a 01 48 63 c9 48 c1 e1 03 eb de <0f>
0b 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 f6 53 48 89
[   93.594676] RIP: nvme_init_request+0x36/0x40 [nvme] RSP: ffffc90002537ca8
[   93.602273] ---[ end trace 810dde3993e5f14e ]---
Reported-by: NYi Zhang <yi.zhang@redhat.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Uses common code for determining if an error should be retried on
alternate path.
Acked-by: NMike Snitzer <snitzer@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>