--- /dev/null
+From 9a24511a01552376ad031ac877b62461d58f6a4d Mon Sep 17 00:00:00 2001
+From: Vasu Dev <vasu.dev@intel.com>
+Date: Thu, 5 Feb 2009 01:32:29 -0800
+References: bnc#473604
+Subject: [PATCH] Out of order tx frames was causing several check condition SCSI status
+ frames followed by these errors in log.
+
+ [sdp] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
+ [sdp] Sense Key : Aborted Command [current]
+ [sdp] Add. Sense: Data phase error
+
+This was causing some test apps to exit due to write failure under heavy
+load.
+
+This was due to a race around adding and removing tx frame skb in
+fcoe_pending_queue, Chris Leech helped me to find that brief unlocking
+period when pulling skb from fcoe_pending_queue in various contexts
+(fcoe_watchdog and fcoe_xmit) and then adding skb back into fcoe_pending_queue
+up on a failed fcoe_start_io could change skb/tx frame order in
+fcoe_pending_queue. Thanks Chris.
+
+This patch allows only single context to pull skb from fcoe_pending_queue
+at any time to prevent above described ordering issue/race by use of
+fcoe_pending_queue_active flag.
+
+This patch simplified fcoe_watchdog with modified fcoe_check_wait_queue by
+use of FCOE_LOW_QUEUE_DEPTH instead previously used several conditionals
+to clear and set lp->qfull.
+
+I think FCOE_MAX_QUEUE_DEPTH with FCOE_LOW_QUEUE_DEPTH will work better
+in re/setting lp->qfull and these could be fine tuned for performance.
+
+Signed-off-by: Vasu Dev <vasu.dev@intel.com>
+Acked-by: John Jolly <jjolly@suse.de>
+---
+ drivers/scsi/fcoe/fcoe_sw.c | 1 +
+ drivers/scsi/fcoe/libfcoe.c | 45 ++++++++++++++++++++----------------------
+ include/scsi/libfcoe.h | 1 +
+ 3 files changed, 23 insertions(+), 24 deletions(-)
+
+diff --git a/drivers/scsi/fcoe/fcoe_sw.c b/drivers/scsi/fcoe/fcoe_sw.c
+index cf83675..da12c93 100644
+--- a/drivers/scsi/fcoe/fcoe_sw.c
++++ b/drivers/scsi/fcoe/fcoe_sw.c
+@@ -191,6 +191,7 @@ static int fcoe_sw_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 Source Mac Address */
+ memcpy(fc->ctl_src_addr, fc->real_dev->dev_addr,
+diff --git a/drivers/scsi/fcoe/libfcoe.c b/drivers/scsi/fcoe/libfcoe.c
+index 8bc8078..9f8204b 100644
+--- a/drivers/scsi/fcoe/libfcoe.c
++++ b/drivers/scsi/fcoe/libfcoe.c
+@@ -49,6 +49,7 @@
+ static int debug_fcoe;
+
+ #define FCOE_MAX_QUEUE_DEPTH 256
++#define FCOE_LOW_QUEUE_DEPTH 32
+
+ /* destination address mode */
+ #define FCOE_GW_ADDR_MODE 0x00
+@@ -727,21 +728,12 @@ static void fcoe_recv_flogi(struct fcoe_softc *fc, struct fc_frame *fp, u8 *sa)
+ **/
+ void fcoe_watchdog(ulong vp)
+ {
+- struct fc_lport *lp;
+ struct fcoe_softc *fc;
+- int qfilled = 0;
+
+ read_lock(&fcoe_hostlist_lock);
+ list_for_each_entry(fc, &fcoe_hostlist, list) {
+- lp = fc->lp;
+- if (lp) {
+- if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH)
+- qfilled = 1;
+- if (fcoe_check_wait_queue(lp) < FCOE_MAX_QUEUE_DEPTH) {
+- if (qfilled)
+- lp->qfull = 0;
+- }
+- }
++ if (fc->lp)
++ fcoe_check_wait_queue(fc->lp);
+ }
+ read_unlock(&fcoe_hostlist_lock);
+
+@@ -757,8 +749,8 @@ void fcoe_watchdog(ulong vp)
+ *
+ * This empties the wait_queue, dequeue the head of the wait_queue queue
+ * and calls fcoe_start_io() for each packet, if all skb have been
+- * transmitted, return 0 if a error occurs, then restore wait_queue and
+- * try again later.
++ * transmitted, return qlen or -1 if a error occurs, then restore
++ * wait_queue and try again later.
+ *
+ * The wait_queue is used when the skb transmit fails. skb will go
+ * in the wait_queue which will be emptied by the time function OR
+@@ -768,33 +760,38 @@ void fcoe_watchdog(ulong vp)
+ **/
+ static int fcoe_check_wait_queue(struct fc_lport *lp)
+ {
+- int rc;
+ struct sk_buff *skb;
+ struct fcoe_softc *fc;
++ int rc = -1;
+
+ fc = fcoe_softc(lp);
+ spin_lock_bh(&fc->fcoe_pending_queue.lock);
+
+- /*
+- * if interface pending queue full then set qfull in lport.
+- */
+- if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH)
+- lp->qfull = 1;
++ 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) {
++ if (rc)
+ fcoe_insert_wait_queue_head(lp, skb);
+- return rc;
+- }
+ spin_lock_bh(&fc->fcoe_pending_queue.lock);
++ if (rc)
++ break;
+ }
+- if (fc->fcoe_pending_queue.qlen < FCOE_MAX_QUEUE_DEPTH)
++ /*
++ * if interface pending queue is below FCOE_LOW_QUEUE_DEPTH
++ * then clear qfull flag.
++ */
++ if (fc->fcoe_pending_queue.qlen < FCOE_LOW_QUEUE_DEPTH)
+ lp->qfull = 0;
+ }
++ fc->fcoe_pending_queue_active = 0;
++ rc = fc->fcoe_pending_queue.qlen;
++out:
+ spin_unlock_bh(&fc->fcoe_pending_queue.lock);
+- return fc->fcoe_pending_queue.qlen;
++ return rc;
+ }
+
+ /**
+diff --git a/include/scsi/libfcoe.h b/include/scsi/libfcoe.h
+index 89fdbb9..ab09986 100644
+--- a/include/scsi/libfcoe.h
++++ b/include/scsi/libfcoe.h
+@@ -46,6 +46,7 @@ struct fcoe_softc {
+ struct net_device *phys_dev; /* device with ethtool_ops */
+ struct packet_type fcoe_packet_type;
+ struct sk_buff_head fcoe_pending_queue;
++ u8 fcoe_pending_queue_active;
+
+ u8 dest_addr[ETH_ALEN];
+ u8 ctl_src_addr[ETH_ALEN];
+--
+1.5.4.5
+
projects / people / pmueller / ipfire-2.x.git / blobdiff