[PATCH 6/6] IB/srp: Avoid that writing into "add_target" hangs due to a cable pull

[Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>]

If a cable is pulled while srp_connect_target() is in progress
that can result in that function never to return. That makes the
process, e.g. srp_daemon, that invoked this function unkillable.
Avoid this by letting srp_connect_target() finish if the event
IB_CM_TIMEWAIT_EXIT is received. This patch fixes a hang with the
following call trace:
 [<ffffffff814eae85>] schedule_timeout+0x215/0x2e0
 [<ffffffff814eab03>] wait_for_common+0x123/0x180
 [<ffffffff814eac1d>] wait_for_completion+0x1d/0x20
 [<ffffffffa03b398c>] srp_connect_target+0x1dc/0x410 [ib_srp]
 [<ffffffffa03b5809>] srp_create_target+0xba9/0xe70 [ib_srp]
 [<ffffffff8133e590>] dev_attr_store+0x20/0x30
 [<ffffffff811eb8f5>] sysfs_write_file+0xe5/0x170
 [<ffffffff811767c8>] vfs_write+0xb8/0x1a0
 [<ffffffff811770c1>] sys_write+0x51/0x90
 [<ffffffff8100b072>] system_call_fastpath+0x16/0x1b

Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
Cc: Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
Cc: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 0d934b7..dcdaf49 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1873,6 +1873,7 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
 	case IB_CM_TIMEWAIT_EXIT:
 		shost_printk(KERN_ERR, target->scsi_host,
 			     PFX "connection closed\n");
+		comp = 1;
 
 		target->status = 0;
 		break;
-- 
1.8.4.5

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