Given that supporting zcopy immediate data for all IOs requires
iser driver to use its own buffer allocations, we settle with
avoiding data copy for IOs with data length of up to 8K (which
is more latency sensitive anyway).
This trims IO write latency by up to 3us and increase IOPs
by up to 40% by saving CPU time doing sg_copy_from_buffer
(8K IO size is the obvious winner here).
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
iser target batches post recv operations to avoid
the overhead of acquiring the recv queue lock and
posting a HW doorbell for each command.
We change it to be per command in order to support
zcopy immediate data for IOs that fits in the 8K
transfer boundary (in the next patch).
(Fix minor patch fuzz due to ib_mr removal - nab)
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Instead of handing a connection to the iscsi stack
for processing right after accepting (rdma_accept) we only hand
the connection to the iscsi core after we reached to a connected
state (ESTABLISHED CM event). This will prevent two error scenrios:
1. race between rdma connection teardown and iscsi login sequence
reported by Nic in: (ce9a9fc20a "iser-target: Fix REJECT CM event
use-after-free OOPs")
2. target stack shutdown sequence race with constant login attempts by
multiple initiators.
We address this by maintaining two queues at the isert_np level:
- accepted: connections that were accepted but have not reached
connected state (might get rejected, unreachable or error).
- pending: connections in connected state, but have yet to handed
to the iscsi core for login processing. iser connections are promoted
to the pending queue only from the accepted queue.
This way the iscsi core now will only handle functional iser connections
and once we shutdown the target stack, we look for any stales that
got left behind so we can safely release them.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
These are always referenced from np-> so no need
for the prefix.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
The iscsi target core teardown sequence calls wait_conn for
all active commands to finish gracefully by:
- move the queue-pair to error state
- drain all the completions
- wait for the core to finish handling all session commands
However, when tearing down a session while there are sequenced
commands that are still waiting for unsolicited data outs, we can
block forever as these are missing an extra reference put.
We basically need the equivalent of iscsit_free_queue_reqs_for_conn()
which is called after wait_conn has returned. Address this by an
explicit walk on conn_cmd_list and put the extra reference.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
As documented in iscsit_sequence_cmd:
/*
* Existing callers for iscsit_sequence_cmd() will silently
* ignore commands with CMDSN_LOWER_THAN_EXP, so force this
* return for CMDSN_MAXCMDSN_OVERRUN as well..
*/
We need to silently finish a command when it's in ISTATE_REMOVE.
This fixes an teardown hang we were seeing where a mis-behaved
initiator (triggered by allocation error injections) sent us a
cmdsn which was lower than expected.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Pull SCSI target updates from Nicholas Bellinger:
"Here are the outstanding target-pending updates for v4.3-rc1.
Mostly bug-fixes and minor changes this round. The fallout from the
big v4.2-rc1 RCU conversion have (thus far) been minimal.
The highlights this round include:
- Move sense handling routines into scsi_common code (Sagi)
- Return ABORTED_COMMAND sense key for PI errors (Sagi)
- Add tpg_enabled_sendtargets attribute for disabled iscsi-target
discovery (David)
- Shrink target struct se_cmd by rearranging fields (Roland)
- Drop iSCSI use of mutex around max_cmd_sn increment (Roland)
- Replace iSCSI __kernel_sockaddr_storage with sockaddr_storage (Andy +
Chris)
- Honor fabric max_data_sg_nents I/O transfer limit (Arun + Himanshu +
nab)
- Fix EXTENDED_COPY >= v4.1 regression OOPsen (Alex + nab)"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (37 commits)
target: use stringify.h instead of own definition
target/user: Fix UFLAG_UNKNOWN_OP handling
target: Remove no-op conditional
target/user: Remove unused variable
target: Fix max_cmd_sn increment w/o cmdsn mutex regressions
target: Attach EXTENDED_COPY local I/O descriptors to xcopy_pt_sess
target/qla2xxx: Honor max_data_sg_nents I/O transfer limit
target/iscsi: Replace __kernel_sockaddr_storage with sockaddr_storage
target/iscsi: Replace conn->login_ip with login_sockaddr
target/iscsi: Keep local_ip as the actual sockaddr
target/iscsi: Fix np_ip bracket issue by removing np_ip
target: Drop iSCSI use of mutex around max_cmd_sn increment
qla2xxx: Update tcm_qla2xxx module description to 24xx+
iscsi-target: Add tpg_enabled_sendtargets for disabled discovery
drivers: target: Drop unlikely before IS_ERR(_OR_NULL)
target: check DPO/FUA usage for COMPARE AND WRITE
target: Shrink struct se_cmd by rearranging fields
target: Remove cmd->se_ordered_id (unused except debug log lines)
target: add support for START_STOP_UNIT SCSI opcode
target: improve unsupported opcode message
...
We expect send only joins to fail, it just means there are no listeners
for the group. The correct thing to do is silently drop the packet
at source.
Eg avahi will full join 224.0.0.251 which causes a send only IGMP packet
to 224.0.0.22, and then a warning level kmessage like this:
ib0: sendonly multicast join failed for ff12:401b:ffff:0000:0000:0000:0000:0016, status -22
If there is no IP router listening to IGMP.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Even though we don't expect the group to be created by the SM we
sill need to provide all the parameters to force the SM to validate
they are correct.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
srp_destroy_qp is designed to indicate we are safe to continue with
freeing the channel resources by modifying the qp error state,
posting a dummy wr on the queue-pair and waiting for it to flush.
This also holds for the channel registration pool as we are unmapping
the memory region when handling a scsi response. Destroying the
channel registration pool before we make sure we processed all the
inflight IO might introduce a use-after-free of the registration pool.
This use-after-free is demonstrated in the stack trace below where
srp is trying to unmap a used FMR after the fmr_pool was already destroyed.
general protection fault: 0000 [#1] SMP
RIP: 0010:[<ffffffff8151121b>] [<ffffffff8151121b>] _raw_spin_lock_irqsave+0x1b/0x50
Call Trace:
[<ffffffffa055d88a>] ib_fmr_pool_unmap+0x1a/0xb0 [ib_core]
[<ffffffffa06c00ed>] srp_unmap_data.isra.28+0x17d/0x250 [ib_srp]
[<ffffffffa06c01eb>] srp_free_req+0x2b/0x60 [ib_srp]
[<ffffffffa06c0c94>] srp_recv_completion+0x174/0x580 [ib_srp]
[<ffffffffa04580fe>] mlx4_eq_int+0x4de/0xe50 [mlx4_core]
[<ffffffffa0458b00>] mlx4_msi_x_interrupt+0x10/0x20 [mlx4_core]
[<ffffffff810abc45>] handle_irq_event_percpu+0x35/0x1b0
[<ffffffff810abdf2>] handle_irq_event+0x32/0x50
[<ffffffff810ae5cf>] handle_edge_irq+0x6f/0x120
[<ffffffff8100455a>] handle_irq+0x1a/0x30
[<ffffffff8151b475>] do_IRQ+0x45/0xb0
[<ffffffff8151162d>] common_interrupt+0x6d/0x6d
[<ffffffff813e4d2f>] cpuidle_enter_state+0x4f/0xc0
[<ffffffff813e4e6c>] cpuidle_idle_call+0xcc/0x210
[<ffffffff8100b9ea>] arch_cpu_idle+0xa/0x30
[<ffffffff810ab1e1>] cpu_startup_entry+0xe1/0x270
[<ffffffff81030b3a>] start_secondary+0x21a/0x2c0
Reported-by: Eliott Kespi <eliottk@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
The majority of callers never check the return value, and even if they
did, they can't do anything about a failure.
All possible failure cases represent a bug in the caller, so just
WARN_ON inside the function instead.
This fixes a few random errors:
net/rd/iw.c infinite loops while it fails. (racing with EBUSY?)
This also lays the ground work to get rid of error return from the
drivers. Most drivers do not error, the few that do are broken since
it cannot be handled.
Since uverbs can legitimately make use of EBUSY, open code the
check.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
The SRP initiator only needs this if the insecure register_always=N
performance optimization is enabled, or if FRWR/FMR is not supported
in the driver.
Do not create an all physical MR unless it is needed to support
either of those modes. Default register_always to true so the out of
the box configuration does not create an insecure all physical MR.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
[bvanassche: reworked and rebased this patch]
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Instead of always using the global rkey for the indirect data
buffer descriptor, register that descriptor with the HCA if
the kernel module parameter register_always has been set to Y.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Introduce the variable srp_device.use_fmr. Leave out the dev->has_fr /
dev->has_fmr and ch->fr_pool / ch->fmr_pool checks since these are
redundant. This patch does not change any functionality but makes the
source code easier to read.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Move the srp_map_desc() call from inside srp_map_sg_entry() to
srp_map_sg() such that the use_mr argument can be removed from
srp_map_sg_entry().
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Mapping a discontiguous sg-list requires multiple memory regions
and hence can exhaust the memory region pool. The SRP initiator
already handles this by temporarily reducing the queue depth. This
means that it is safe to remove the memory registration backtracking
code. This patch has been tested with direct I/O sizes up to 256 MB.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Although most paths through which a request is submitted check
block layer parameters like the max_segments limit, these are
not checked when an SG_IO or direct I/O request is submitted.
Hence add a range check for the memory descriptor array pointer.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Instead of using the global rkey for large memory regions, use
multiple registrations. See also the while (dma_len) loop further
down in srp_map_sg_entry().
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
During a discussion in 2011 nobody recalled why FMR was not used for
non-page aligned buffers (see also
http://thread.gmane.org/gmane.linux.drivers.rdma/7149). Re-enable FMR
for such buffers. For the reason why the srp_map_fmr() function needs
to be modified, see also patch "IB/srp: rework mapping engine to use
multiple FMR entries" (commit ID 8f26c9ff9cd0; January 2011).
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
The pd now has a local_dma_lkey member which completely replaces
ib_get_dma_mr, use it instead.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Replace all leys with pd->local_dma_lkey. This driver does not support
iWarp, so this is safe.
The insecure use of ib_get_dma_mr is thus isolated to an rkey, and will
have to be fixed separately.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
The pd now has a local_dma_lkey member which completely replaces
ib_get_dma_mr, use it instead.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Replace all leys with pd->local_dma_lkey. This driver does not support
iWarp, so this is safe.
The insecure use of ib_get_dma_mr is thus isolated to an rkey, and this
looks trivially fixed by forcing the use of registration in a future
patch.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
The pd now has a local_dma_lkey member which completely replaces
ib_get_dma_mr, use it instead.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Chaning of send work requests benefits performance by
reducing the send queue lock contention (acquired in
ib_post_send) and saves us HW doorbells which is posted
only once.
Currently, in normal IO flows iser does not chain the CDB send
work request with the registration work request. Also in PI
flows, signature work requests are not chained as well.
Lets chain those and post only once.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Easier to debug when we have the registration details.
This patch does not change any functionality.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
iser support up to 512KB data transfer in a single scsi command.
This means that larger IOs will split to different request. While
iser can easily saturate FDR/EDR wires, some arrays are fine tuned
for 1MB (or larger) IO sizes, hence add an option to support larger
transfers (up to 8MB) if the device allows it.
Given that a few target implementations don't support data transfers
of more than 512KB by default and the fact that larger IO sizes require
more resources, we introduce a module parameter to determine the
maximum number of 512B sectors in a single scsi command.
Users that are interested in larger transfers can change this value given
that the target supports larger transfers.
At the moment, iser works in 4K pages granularity, In a later stage
we will get it to work with system page size instead.
IO operations that consists of N pages will need a page vector
of size N+1 in case the first SG element contains an offset. Given
that some devices allocates memory regions in powers of 2, this
means that allocating a region with N+1 pages, will result in
region resources allocation of the next power of 2. Since we don't
want that to happen, in case we are in the limit of IO size supported
and the first SG element has an offset, we align the SG list using a
bounce buffer (which is OK given that this is not likely to happen a lot).
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Hard coded for now. This will allow to allocate different
sized MRs depending on the IO size needed (and device
capabilities).
This patch does not change any functionality.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
iser_reg_rdma_mem_[fastreg|fmr] share a lot of code, and
logically do the same thing other than the buffer registration
method itself (iser_fast_reg_mr vs. iser_fast_reg_fmr).
The DIF logic is not implemented in the FMR flow as there is no
existing device that supports FMRs and Signature feature.
This patch unifies the flow in a single routine iser_reg_rdma_mem
and just split to fmr/frwr for the buffer registration itself.
Also, for symmetry reasons, unify iser_unreg_rdma_mem (which will
call the relevant device specific unreg routine).
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
As for fmrs we will hold a single registration descriptor
as no need for multiple like in the frwr mode (descriptor
for each task). This change helps unifying the duplicate
registration code paths.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Also, change a name of a local variable.
This patch does not change any functionality.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This will allow us to unify the memory registration code path between
the various methods which vary by the device capabilities. This change
will make it easier and less intrusive to remove fmr_pools from the
code when we'd want to.
The reason we use a single descriptor is to avoid taking a
redundant spinlock when working with FMRs.
We also change the signature of iser_reg_page_vec to make it match
iser_fast_reg_mr (and the future indirect registration method).
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Instead of having it a part of the connection structure,
have it be under a dedicated (embedded) structure in the
connection. A logical separation of the registration pool
and the connection structure.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Don't have the caller allocate the structure and worry about
freeing it in case the routine failed.
This patch does not change any functionality.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Move all the per-device function pointers to an easy
extensible iser_reg_ops structure that contains all
the iser registration operations.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
In the past the we always tried to allocate an fmr_pool
and if it failed on ENOSYS (not supported) then we continued
with dma mr. This is not the case anymore and if we tried to
allocate an fmr_pool then it is supported and we expect to succeed.
Also, the check if fmr_pool is allocated when free is called is
redundant as well as we are guaranteed it exists.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Avoid struct names without iser_ prefix.
This patch does not change any functionality.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Have fast_reg_descriptor hold struct iser_reg_resources
(mr, frpl, valid flag). This will be useful when the
actual buffer registration routines will be passed with
the needed registration resources (i.e. iser_reg_resources)
without being aware of their nature (i.e. data or protection).
In order to achieve this, we remove reg_indicators flags container
and place specific flags (mr_valid) within iser_reg_resources struct.
We also place the sig_mr_valid and sig_protcted flags in iser_pi_context.
This patch also modifies iser_fast_reg_mr to receive the
reg_resources instead of the fast_reg_descriptor and a data/protection
indicator.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
We can do it in iser_aligned_data_len instead and
it will save us an argument that is passed to
fall_to_counce_buf just for the print.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
We always call iser_initialize_task_headers() and set
the header tx_sg.lkey to the device mr lkey, so no
point in checking it in iser_create_send_desc().
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
If iser_initialize_task_headers() routine failed before
dma mapping, we should not attempt to unmap in cleanup_task().
Fixes: 7414dde0a6 (IB/iser: Fix race between iser connection ...)
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
We don't update those anywhere in the code and they
seem pretty useless (no one seem to care about those).
qp_tx_queue_full: We never should get this
fmr_map_not_avail: We can never get to this
eh_abort_cnt: We don't monitor aborts
Go ahead and remove them.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Since commit "IB/iser: Fix race between iser connection teardown..."
iser_initialize_task_headers() might fail, so we need to check that.
Fixes: 7414dde0a6 (IB/iser: Fix race between iser connection ...)
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
While we're at it, use permission defines instead
of octal values and rearrange a little bit.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
scsi_host_alloc() not only allocates memory for a SCSI host but also
creates the scsi_eh_<n> kernel thread and the scsi_tmf_<n> workqueue.
Stop these threads if login fails by calling scsi_host_put().
Reported-by: Konstantin Krotov <kkv@clodo.ru>
Fixes: fb49c8bbaa ("Remove an extraneous scsi_host_put() from an error path")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.19
Signed-off-by: Doug Ledford <dledford@redhat.com>
Since version 1.0 e.g. scsi-mq has been added. Since this is
a significant change, bump the driver version and release date.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Avoid that the following kernel warning is reported if the SRP
target system accepts fewer channels per connection than what
was requested by the initiator system:
WARNING: at drivers/infiniband/ulp/srp/ib_srp.c:617 srp_destroy_qp+0xb1/0x120 [ib_srp]()
Call Trace:
[<ffffffff8105d67f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8105d6da>] warn_slowpath_null+0x1a/0x20
[<ffffffffa05419e1>] srp_destroy_qp+0xb1/0x120 [ib_srp]
[<ffffffffa05445fb>] srp_create_ch_ib+0x19b/0x420 [ib_srp]
[<ffffffffa0545257>] srp_create_target+0x7d7/0xa94 [ib_srp]
[<ffffffff8138dac0>] dev_attr_store+0x20/0x30
[<ffffffff812079ef>] sysfs_write_file+0xef/0x170
[<ffffffff81191fc4>] vfs_write+0xb4/0x130
[<ffffffff8119276f>] sys_write+0x5f/0xa0
[<ffffffff815a0a59>] system_call_fastpath+0x16/0x1b
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Doug Ledford <dledford@redhat.com>
