IB/srp: consolidate state change code

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
[ broken out and small cleanups by David Dillow ]
Signed-off-by: David Dillow <dillowda@ornl.gov>

1 files changed, 24 insertions, 21 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 29429a13fd90..def9e6b38459 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -441,18 +441,28 @@ static void srp_disconnect_target(struct srp_target_port *target)
         wait_for_completion(&target->done);
 }
 
+static bool srp_change_state(struct srp_target_port *target,
+                            enum srp_target_state old,
+                            enum srp_target_state new)
+{
+        bool changed = false;
+
+        spin_lock_irq(target->scsi_host->host_lock);
+        if (target->state == old) {
+                target->state = new;
+                changed = true;
+        }
+        spin_unlock_irq(target->scsi_host->host_lock);
+        return changed;
+}
+
 static void srp_remove_work(struct work_struct *work)
 {
         struct srp_target_port *target =
                 container_of(work, struct srp_target_port, work);
 
-        spin_lock_irq(target->scsi_host->host_lock);
-        if (target->state != SRP_TARGET_DEAD) {
-                spin_unlock_irq(target->scsi_host->host_lock);
+        if (!srp_change_state(target, SRP_TARGET_DEAD, SRP_TARGET_REMOVED))
                 return;
-        }
-        target->state = SRP_TARGET_REMOVED;
-        spin_unlock_irq(target->scsi_host->host_lock);
 
         spin_lock(&target->srp_host->target_lock);
         list_del(&target->list);
@@ -560,13 +570,8 @@ static int srp_reconnect_target(struct srp_target_port *target)
         struct ib_wc wc;
         int ret;
 
-        spin_lock_irq(target->scsi_host->host_lock);
-        if (target->state != SRP_TARGET_LIVE) {
-                spin_unlock_irq(target->scsi_host->host_lock);
+        if (!srp_change_state(target, SRP_TARGET_LIVE, SRP_TARGET_CONNECTING))
                 return -EAGAIN;
-        }
-        target->state = SRP_TARGET_CONNECTING;
-        spin_unlock_irq(target->scsi_host->host_lock);
 
         srp_disconnect_target(target);
         /*
@@ -605,13 +610,8 @@ static int srp_reconnect_target(struct srp_target_port *target)
         if (ret)
                 goto err;
 
-        spin_lock_irq(target->scsi_host->host_lock);
-        if (target->state == SRP_TARGET_CONNECTING) {
-                ret = 0;
-                target->state = SRP_TARGET_LIVE;
-        } else
+        if (!srp_change_state(target, SRP_TARGET_CONNECTING, SRP_TARGET_LIVE))
                 ret = -EAGAIN;
-        spin_unlock_irq(target->scsi_host->host_lock);
 
         return ret;
 
@@ -621,9 +621,12 @@ err:
 
         /*
          * We couldn't reconnect, so kill our target port off.
-         * However, we have to defer the real removal because we might
-         * be in the context of the SCSI error handler now, which
-         * would deadlock if we call scsi_remove_host().
+         * However, we have to defer the real removal because we
+         * are in the context of the SCSI error handler now, which
+         * will deadlock if we call scsi_remove_host().
+         *
+         * Schedule our work inside the lock to avoid a race with
+         * the flush_scheduled_work() in srp_remove_one().
          */
         spin_lock_irq(target->scsi_host->host_lock);
         if (target->state == SRP_TARGET_CONNECTING) {