IB/srp: Increase block layer timeout

Increase the block layer timeout for disks so that it is above the
InfiniBand transport layer timeout.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 922d845f76b0..5aa70e96ec90 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1419,6 +1419,33 @@ err:
         return -ENOMEM;
 }
 
+static uint32_t srp_compute_rq_tmo(struct ib_qp_attr *qp_attr, int attr_mask)
+{
+        uint64_t T_tr_ns, max_compl_time_ms;
+        uint32_t rq_tmo_jiffies;
+
+        /*
+         * According to section 11.2.4.2 in the IBTA spec (Modify Queue Pair,
+         * table 91), both the QP timeout and the retry count have to be set
+         * for RC QP's during the RTR to RTS transition.
+         */
+        WARN_ON_ONCE((attr_mask & (IB_QP_TIMEOUT | IB_QP_RETRY_CNT)) !=
+                     (IB_QP_TIMEOUT | IB_QP_RETRY_CNT));
+
+        /*
+         * Set target->rq_tmo_jiffies to one second more than the largest time
+         * it can take before an error completion is generated. See also
+         * C9-140..142 in the IBTA spec for more information about how to
+         * convert the QP Local ACK Timeout value to nanoseconds.
+         */
+        T_tr_ns = 4096 * (1ULL << qp_attr->timeout);
+        max_compl_time_ms = qp_attr->retry_cnt * 4 * T_tr_ns;
+        do_div(max_compl_time_ms, NSEC_PER_MSEC);
+        rq_tmo_jiffies = msecs_to_jiffies(max_compl_time_ms + 1000);
+
+        return rq_tmo_jiffies;
+}
+
 static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
                                struct srp_login_rsp *lrsp,
                                struct srp_target_port *target)
@@ -1478,6 +1505,8 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
         if (ret)
                 goto error_free;
 
+        target->rq_tmo_jiffies = srp_compute_rq_tmo(qp_attr, attr_mask);
+
         ret = ib_modify_qp(target->qp, qp_attr, attr_mask);
         if (ret)
                 goto error_free;
@@ -1729,6 +1758,21 @@ static int srp_reset_host(struct scsi_cmnd *scmnd)
         return ret;
 }
 
+static int srp_slave_configure(struct scsi_device *sdev)
+{
+        struct Scsi_Host *shost = sdev->host;
+        struct srp_target_port *target = host_to_target(shost);
+        struct request_queue *q = sdev->request_queue;
+        unsigned long timeout;
+
+        if (sdev->type == TYPE_DISK) {
+                timeout = max_t(unsigned, 30 * HZ, target->rq_tmo_jiffies);
+                blk_queue_rq_timeout(q, timeout);
+        }
+
+        return 0;
+}
+
 static ssize_t show_id_ext(struct device *dev, struct device_attribute *attr,
                            char *buf)
 {
@@ -1861,6 +1905,7 @@ static struct scsi_host_template srp_template = {
         .module                         = THIS_MODULE,
         .name                           = "InfiniBand SRP initiator",
         .proc_name                      = DRV_NAME,
+        .slave_configure                = srp_slave_configure,
         .info                           = srp_target_info,
         .queuecommand                   = srp_queuecommand,
         .eh_abort_handler               = srp_abort,