IB/srp: Add periodic reconnect functionality
After a transport layer occurred, periodically try to reconnect
to the target until the dev_loss timer expires. Protect the
callback functions that can be invoked from inside the SCSI EH
against concurrent invocation with srp_reconnect_rport() via the
rport mutex. Change the default dev_loss_tmo from 60s into 600s
to give the reconnect mechanism a chance to kick in.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 99c893d..ebbe01b 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -88,6 +88,11 @@
static struct kernel_param_ops srp_tmo_ops;
+static int srp_reconnect_delay = 10;
+module_param_cb(reconnect_delay, &srp_tmo_ops, &srp_reconnect_delay,
+ S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(reconnect_delay, "Time between successive reconnect attempts");
+
static int srp_fast_io_fail_tmo = 15;
module_param_cb(fast_io_fail_tmo, &srp_tmo_ops, &srp_fast_io_fail_tmo,
S_IRUGO | S_IWUSR);
@@ -96,7 +101,7 @@
" layer error and failing all I/O. \"off\" means that this"
" functionality is disabled.");
-static int srp_dev_loss_tmo = 60;
+static int srp_dev_loss_tmo = 600;
module_param_cb(dev_loss_tmo, &srp_tmo_ops, &srp_dev_loss_tmo,
S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dev_loss_tmo,
@@ -144,10 +149,14 @@
} else {
tmo = -1;
}
- if (kp->arg == &srp_fast_io_fail_tmo)
- res = srp_tmo_valid(-1, tmo, srp_dev_loss_tmo);
+ if (kp->arg == &srp_reconnect_delay)
+ res = srp_tmo_valid(tmo, srp_fast_io_fail_tmo,
+ srp_dev_loss_tmo);
+ else if (kp->arg == &srp_fast_io_fail_tmo)
+ res = srp_tmo_valid(srp_reconnect_delay, tmo, srp_dev_loss_tmo);
else
- res = srp_tmo_valid(-1, srp_fast_io_fail_tmo, tmo);
+ res = srp_tmo_valid(srp_reconnect_delay, srp_fast_io_fail_tmo,
+ tmo);
if (res)
goto out;
*(int *)kp->arg = tmo;
@@ -1426,18 +1435,29 @@
static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
{
struct srp_target_port *target = host_to_target(shost);
+ struct srp_rport *rport = target->rport;
struct srp_request *req;
struct srp_iu *iu;
struct srp_cmd *cmd;
struct ib_device *dev;
unsigned long flags;
int len, result;
+ const bool in_scsi_eh = !in_interrupt() && current == shost->ehandler;
+
+ /*
+ * The SCSI EH thread is the only context from which srp_queuecommand()
+ * can get invoked for blocked devices (SDEV_BLOCK /
+ * SDEV_CREATED_BLOCK). Avoid racing with srp_reconnect_rport() by
+ * locking the rport mutex if invoked from inside the SCSI EH.
+ */
+ if (in_scsi_eh)
+ mutex_lock(&rport->mutex);
result = srp_chkready(target->rport);
if (unlikely(result)) {
scmnd->result = result;
scmnd->scsi_done(scmnd);
- return 0;
+ goto unlock_rport;
}
spin_lock_irqsave(&target->lock, flags);
@@ -1482,6 +1502,10 @@
goto err_unmap;
}
+unlock_rport:
+ if (in_scsi_eh)
+ mutex_unlock(&rport->mutex);
+
return 0;
err_unmap:
@@ -1496,6 +1520,9 @@
err_unlock:
spin_unlock_irqrestore(&target->lock, flags);
+ if (in_scsi_eh)
+ mutex_unlock(&rport->mutex);
+
return SCSI_MLQUEUE_HOST_BUSY;
}
@@ -1780,6 +1807,7 @@
static int srp_send_tsk_mgmt(struct srp_target_port *target,
u64 req_tag, unsigned int lun, u8 func)
{
+ struct srp_rport *rport = target->rport;
struct ib_device *dev = target->srp_host->srp_dev->dev;
struct srp_iu *iu;
struct srp_tsk_mgmt *tsk_mgmt;
@@ -1789,12 +1817,20 @@
init_completion(&target->tsk_mgmt_done);
+ /*
+ * Lock the rport mutex to avoid that srp_create_target_ib() is
+ * invoked while a task management function is being sent.
+ */
+ mutex_lock(&rport->mutex);
spin_lock_irq(&target->lock);
iu = __srp_get_tx_iu(target, SRP_IU_TSK_MGMT);
spin_unlock_irq(&target->lock);
- if (!iu)
+ if (!iu) {
+ mutex_unlock(&rport->mutex);
+
return -1;
+ }
ib_dma_sync_single_for_cpu(dev, iu->dma, sizeof *tsk_mgmt,
DMA_TO_DEVICE);
@@ -1811,8 +1847,11 @@
DMA_TO_DEVICE);
if (srp_post_send(target, iu, sizeof *tsk_mgmt)) {
srp_put_tx_iu(target, iu, SRP_IU_TSK_MGMT);
+ mutex_unlock(&rport->mutex);
+
return -1;
}
+ mutex_unlock(&rport->mutex);
if (!wait_for_completion_timeout(&target->tsk_mgmt_done,
msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS)))
@@ -2713,6 +2752,7 @@
static struct srp_function_template ib_srp_transport_functions = {
.has_rport_state = true,
.reset_timer_if_blocked = true,
+ .reconnect_delay = &srp_reconnect_delay,
.fast_io_fail_tmo = &srp_fast_io_fail_tmo,
.dev_loss_tmo = &srp_dev_loss_tmo,
.reconnect = srp_rport_reconnect,