[PATCH 3.16 057/158] scsi_transport_srp: Fix fast_io_fail_tmo=dev_loss_tmo=off behavior

[Greg Kroah-Hartman]

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Bart Van Assche <bvanassche@xxxxxxx>

commit cd53eb686d2418eda938aad3c9da42b7dfa9351f upstream.

If scsi_remove_host() is called while an rport is in the blocked state
then scsi_remove_host() will only finish if the rport is unblocked
from inside a timer function. Make sure that an rport only enters the
blocked state if a timer will be started that will unblock it. This
avoids that unloading the ib_srp kernel module after having
disconnected the initiator from the target system results in a
deadlock if both the fast_io_fail_tmo and dev_loss_tmo parameters have
been set to "off".

Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Reviewed-by: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Reviewed-by: David Dillow <dave@xxxxxxxxxxxxxx>
Signed-off-by: Roland Dreier <roland@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/scsi/scsi_transport_srp.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -473,7 +473,8 @@ static void __srp_start_tl_fail_timers(s
 	if (delay > 0)
 		queue_delayed_work(system_long_wq, &rport->reconnect_work,
 				   1UL * delay * HZ);
-	if (srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
+	if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
+	    srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 		pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
 			 rport->state);
 		scsi_target_block(&shost->shost_gendev);


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