scsi_transport_srp: Fix fast_io_fail_tmo=dev_loss_tmo=off behavior

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@acm.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: David Dillow <dave@thedillows.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index 13e898332e45b066617b3089ac41d4efdad3217d..a0c5bfdc5366f3d2b9e76805d77b7db72f9b8399 100644 (file)
--- 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(struct srp_rport *rport)
        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);