[PATCH 02/12] scsi_transport_srp: Fix a race condition

Bart Van Assche
2015-04-30T08:57:10Z

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@sandisk.com>
Cc: James Bottomley <JBottomley@Odin.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #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);
+ }
}

/**
--
2.1.4