[SCSI] fcoe: removes fcoe_watchdog

Removes periodic fcoe_watchdog timer used across all fcoe interface
maintained in fcoe_hostlist instead added new fcoe_queue_timer
per fcoe interface.

Added timer is armed only when some pending skb need to be flushed
as oppose to periodic 1 second fcoe_watchdog, since now
fcoe_queue_timer is used on demand thus set this to 2 jiffies.

Now fcoe_queue_timer is much simple than fcoe_watchdog using lock to
process all fcoe interface from fcoe_hostlist.

I noticed +ve performance result with using 2 jiffies timer as
this helps flushing fcoe_pending_queue quickly.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

2 files changed, 19 insertions, 34 deletions

diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index 30eba75a5cd..6e7a700f5d5 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -54,7 +54,6 @@ MODULE_LICENSE("GPL v2");
 /* fcoe host list */
 LIST_HEAD(fcoe_hostlist);
 DEFINE_RWLOCK(fcoe_hostlist_lock);
-DEFINE_TIMER(fcoe_timer, NULL, 0, 0);
 DEFINE_PER_CPU(struct fcoe_percpu_s, fcoe_percpu);
 
 /* Function Prototypes */
@@ -168,6 +167,18 @@ static int fcoe_lport_config(struct fc_lport *lp)
 }
 
 /**
+ * fcoe_queue_timer() - fcoe queue timer
+ * @lp: the fc_lport pointer
+ *
+ * Calls fcoe_check_wait_queue on timeout
+ *
+ */
+static void fcoe_queue_timer(ulong lp)
+{
+        fcoe_check_wait_queue((struct fc_lport *)lp, NULL);
+}
+
+/**
  * fcoe_netdev_config() - Set up netdev for SW FCoE
  * @lp : ptr to the fc_lport
  * @netdev : ptr to the associated netdevice struct
@@ -237,6 +248,7 @@ static int fcoe_netdev_config(struct fc_lport *lp, struct net_device *netdev)
         }
         skb_queue_head_init(&fc->fcoe_pending_queue);
         fc->fcoe_pending_queue_active = 0;
+        setup_timer(&fc->timer, fcoe_queue_timer, (unsigned long)lp);
 
         /* setup Source Mac Address */
         memcpy(fc->ctlr.ctl_src_addr, fc->real_dev->dev_addr,
@@ -387,6 +399,9 @@ static int fcoe_if_destroy(struct net_device *netdev)
         /* Free existing skbs */
         fcoe_clean_pending_queue(lp);
 
+        /* Stop the timer */
+        del_timer_sync(&fc->timer);
+
         /* Free memory used by statistical counters */
         fc_lport_free_stats(lp);
 
@@ -1260,32 +1275,6 @@ int fcoe_percpu_receive_thread(void *arg)
 }
 
 /**
- * fcoe_watchdog() - fcoe timer callback
- * @vp:
- *
- * This checks the pending queue length for fcoe and set lport qfull
- * if the FCOE_MAX_QUEUE_DEPTH is reached. This is done for all fc_lport on the
- * fcoe_hostlist.
- *
- * Returns: 0 for success
- */
-void fcoe_watchdog(ulong vp)
-{
-        struct fcoe_softc *fc;
-
-        read_lock(&fcoe_hostlist_lock);
-        list_for_each_entry(fc, &fcoe_hostlist, list) {
-                if (fc->ctlr.lp)
-                        fcoe_check_wait_queue(fc->ctlr.lp, NULL);
-        }
-        read_unlock(&fcoe_hostlist_lock);
-
-        fcoe_timer.expires = jiffies + (1 * HZ);
-        add_timer(&fcoe_timer);
-}
-
-
-/**
  * fcoe_check_wait_queue() - attempt to clear the transmit backlog
  * @lp: the fc_lport
  *
@@ -1333,6 +1322,8 @@ static void fcoe_check_wait_queue(struct fc_lport *lp, struct sk_buff *skb)
 
         if (fc->fcoe_pending_queue.qlen < FCOE_LOW_QUEUE_DEPTH)
                 lp->qfull = 0;
+        if (fc->fcoe_pending_queue.qlen && !timer_pending(&fc->timer))
+                mod_timer(&fc->timer, jiffies + 2);
         fc->fcoe_pending_queue_active = 0;
 out:
         if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH)
@@ -1809,10 +1800,6 @@ static int __init fcoe_init(void)
         /* Setup link change notification */
         fcoe_dev_setup();
 
-        setup_timer(&fcoe_timer, fcoe_watchdog, 0);
-
-        mod_timer(&fcoe_timer, jiffies + (10 * HZ));
-
         fcoe_if_init();
 
         return 0;
@@ -1838,9 +1825,6 @@ static void __exit fcoe_exit(void)
 
         fcoe_dev_cleanup();
 
-        /* Stop the timer */
-        del_timer_sync(&fcoe_timer);
-
         /* releases the associated fcoe hosts */
         list_for_each_entry_safe(fc, tmp, &fcoe_hostlist, list)
                 fcoe_if_destroy(fc->real_dev);
diff --git a/drivers/scsi/fcoe/fcoe.h b/drivers/scsi/fcoe/fcoe.h
index 917aae88689..a1eb8c1988b 100644
--- a/drivers/scsi/fcoe/fcoe.h
+++ b/drivers/scsi/fcoe/fcoe.h
@@ -61,6 +61,7 @@ struct fcoe_softc {
         struct packet_type  fip_packet_type;
         struct sk_buff_head fcoe_pending_queue;
         u8      fcoe_pending_queue_active;
+        struct timer_list timer;                /* queue timer */
         struct fcoe_ctlr ctlr;
 };