Move xen patchset to new version's subdir.

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.31 / patches.drivers / fcoe-fix-handling-of-pending-queue

From b32a88ad3782fbaa3cb851ebc1b694ba09840c86 Mon Sep 17 00:00:00 2001
From: Chris Leech <christopher.leech@intel.com>
Date: Thu, 19 Feb 2009 14:37:47 -0800
Subject: fcoe: fix handling of pending queue, prevent out of order frames
References: bnc#477953

The per-lport pending queue handling can result in a frame being retried
from a different CPU than it was originally sent from.  The scope of the
queue lock is not large enough to prevent reordering of frames within a
sequence in that case.

Before this change I would see out of order frames on large write IOs,
leading to frequent exchange timeouts and retries.

With the locking scope changed, the fcoe_insert_wait_queue(_head) helpers
no longer do anything useful, so I removed them as well.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/fcoe/libfcoe.c |   64 +++++++++----------------------------------
 1 files changed, 13 insertions(+), 51 deletions(-)

diff --git a/drivers/scsi/fcoe/libfcoe.c b/drivers/scsi/fcoe/libfcoe.c
index ada3ebb..d3f4eb9 100644
--- a/drivers/scsi/fcoe/libfcoe.c
+++ b/drivers/scsi/fcoe/libfcoe.c
@@ -71,8 +71,6 @@ struct fcoe_percpu_s *fcoe_percpu[NR_CPUS];
 
 /* Function Prototyes */
 static int fcoe_check_wait_queue(struct fc_lport *);
-static void fcoe_insert_wait_queue_head(struct fc_lport *, struct sk_buff *);
-static void fcoe_insert_wait_queue(struct fc_lport *, struct sk_buff *);
 static void fcoe_recv_flogi(struct fcoe_softc *, struct fc_frame *, u8 *);
 #ifdef CONFIG_HOTPLUG_CPU
 static int fcoe_cpu_callback(struct notifier_block *, ulong, void *);
@@ -497,6 +495,7 @@ int fcoe_xmit(struct fc_lport *lp, struct fc_frame *fp)
 
 	/* send down to lld */
 	fr_dev(fp) = lp;
+	spin_lock_bh(&fc->fcoe_pending_queue.lock);
 	if (fc->fcoe_pending_queue.qlen)
 		rc = fcoe_check_wait_queue(lp);
 
@@ -504,10 +503,11 @@ int fcoe_xmit(struct fc_lport *lp, struct fc_frame *fp)
 		rc = fcoe_start_io(skb);
 
 	if (rc) {
-		fcoe_insert_wait_queue(lp, skb);
+		__skb_queue_tail(&fc->fcoe_pending_queue, skb);
 		if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH)
 			lp->qfull = 1;
 	}
+	spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 
 	return 0;
 }
@@ -732,8 +732,11 @@ void fcoe_watchdog(ulong vp)
 
 	read_lock(&fcoe_hostlist_lock);
 	list_for_each_entry(fc, &fcoe_hostlist, list) {
-		if (fc->lp)
+		if (fc->lp) {
+			spin_lock_bh(&fc->fcoe_pending_queue.lock);
 			fcoe_check_wait_queue(fc->lp);
+			spin_unlock_bh(&fc->fcoe_pending_queue.lock);
+		}
 	}
 	read_unlock(&fcoe_hostlist_lock);
 
@@ -756,6 +759,8 @@ void fcoe_watchdog(ulong vp)
  * in the wait_queue which will be emptied by the time function OR
  * by the next skb transmit.
  *
+ * Locking: fc->fcoe_pending_queue.lock must be held before calling
+ *
  * Returns: 0 for success
  **/
 static int fcoe_check_wait_queue(struct fc_lport *lp)
@@ -765,20 +770,17 @@ static int fcoe_check_wait_queue(struct fc_lport *lp)
 	int rc = -1;
 
 	fc = fcoe_softc(lp);
-	spin_lock_bh(&fc->fcoe_pending_queue.lock);
 
 	if (fc->fcoe_pending_queue_active)
 		goto out;
 	fc->fcoe_pending_queue_active = 1;
 	if (fc->fcoe_pending_queue.qlen) {
 		while ((skb = __skb_dequeue(&fc->fcoe_pending_queue)) != NULL) {
-			spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 			rc = fcoe_start_io(skb);
-			if (rc)
-				fcoe_insert_wait_queue_head(lp, skb);
-			spin_lock_bh(&fc->fcoe_pending_queue.lock);
-			if (rc)
+			if (rc) {
+				__skb_queue_head(&fc->fcoe_pending_queue, skb);
 				break;
+			}
 		}
 		/*
 		 * if interface pending queue is below FCOE_LOW_QUEUE_DEPTH
@@ -790,47 +792,10 @@ static int fcoe_check_wait_queue(struct fc_lport *lp)
 	fc->fcoe_pending_queue_active = 0;
 	rc = fc->fcoe_pending_queue.qlen;
 out:
-	spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 	return rc;
 }
 
 /**
- * fcoe_insert_wait_queue_head - puts skb to fcoe pending queue head
- * @lp: the fc_port for this skb
- * @skb: the associated skb to be xmitted
- *
- * Returns: none
- **/
-static void fcoe_insert_wait_queue_head(struct fc_lport *lp,
-					struct sk_buff *skb)
-{
-	struct fcoe_softc *fc;
-
-	fc = fcoe_softc(lp);
-	spin_lock_bh(&fc->fcoe_pending_queue.lock);
-	__skb_queue_head(&fc->fcoe_pending_queue, skb);
-	spin_unlock_bh(&fc->fcoe_pending_queue.lock);
-}
-
-/**
- * fcoe_insert_wait_queue - put the skb into fcoe pending queue tail
- * @lp: the fc_port for this skb
- * @skb: the associated skb to be xmitted
- *
- * Returns: none
- **/
-static void fcoe_insert_wait_queue(struct fc_lport *lp,
-				   struct sk_buff *skb)
-{
-	struct fcoe_softc *fc;
-
-	fc = fcoe_softc(lp);
-	spin_lock_bh(&fc->fcoe_pending_queue.lock);
-	__skb_queue_tail(&fc->fcoe_pending_queue, skb);
-	spin_unlock_bh(&fc->fcoe_pending_queue.lock);
-}
-
-/**
  * fcoe_dev_setup - setup link change notification interface
  *
  **/
@@ -1187,11 +1152,8 @@ void fcoe_clean_pending_queue(struct fc_lport *lp)
 	struct sk_buff *skb;
 
 	spin_lock_bh(&fc->fcoe_pending_queue.lock);
-	while ((skb = __skb_dequeue(&fc->fcoe_pending_queue)) != NULL) {
-		spin_unlock_bh(&fc->fcoe_pending_queue.lock);
+	while ((skb = __skb_dequeue(&fc->fcoe_pending_queue)) != NULL)
 		kfree_skb(skb);
-		spin_lock_bh(&fc->fcoe_pending_queue.lock);
-	}
 	spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 }
 EXPORT_SYMBOL_GPL(fcoe_clean_pending_queue);
-- 
1.5.4.5