On 04/30/15 11:44, Sagi Grimberg wrote:
On 4/30/2015 11:57 AM, Bart Van Assche wrote:Avoid that srp_terminate_io() can get invoked while srp_queuecommand() is in progress. This patch avoids that an I/O timeout can trigger the following kernel warning: WARNING: at drivers/infiniband/ulp/srp/ib_srp.c:1447 srp_terminate_io+0xef/0x100 [ib_srp]() Call Trace: [<ffffffff814c65a2>] dump_stack+0x4e/0x68 [<ffffffff81051f71>] warn_slowpath_common+0x81/0xa0 [<ffffffff8105204a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa075f51f>] srp_terminate_io+0xef/0x100 [ib_srp] [<ffffffffa07495da>] __rport_fail_io_fast+0xba/0xc0 [scsi_transport_srp] [<ffffffffa0749a90>] rport_fast_io_fail_timedout+0xe0/0xf0 [scsi_transport_srp] [<ffffffff8106e09b>] process_one_work+0x1db/0x780 [<ffffffff8106e75b>] worker_thread+0x11b/0x450 [<ffffffff81073c64>] kthread+0xe4/0x100 [<ffffffff814cf26c>] ret_from_fork+0x7c/0xb0 See also patch "scsi_transport_srp: Add transport layer error handling" (commit ID 29c17324803c). Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Cc: James Bottomley <JBottomley@xxxxxxxx> Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx> Cc: Sebastian Parschauer <sebastian.riemer@xxxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> #v3.13 --- drivers/scsi/scsi_transport_srp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c index 6ce1c48..4a44337 100644 --- a/drivers/scsi/scsi_transport_srp.c +++ b/drivers/scsi/scsi_transport_srp.c @@ -437,8 +437,10 @@ static void __rport_fail_io_fast(struct srp_rport *rport) /* Involve the LLD if possible to terminate all I/O on the rport. */ i = to_srp_internal(shost->transportt); - if (i->f->terminate_rport_io) + if (i->f->terminate_rport_io) { + srp_wait_for_queuecommand(shost); i->f->terminate_rport_io(rport); + }Why not just terminate the inflight IO before unblocking the target?
Sorry but I don't think that would prevent the described race condition. The call trace in the description of this patch illustrates that srp_queuecommand() can still be active even after the transport state has been changed into "offline". Hence if terminate_rport_io() would be invoked earlier the same race would still exist.
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