src/patches/suse-2.6.27.31/patches.drivers/fcoe-fix-handling-of-pending-queue

   1 From b32a88ad3782fbaa3cb851ebc1b694ba09840c86 Mon Sep 17 00:00:00 2001
   2 From: Chris Leech <christopher.leech@intel.com>
   3 Date: Thu, 19 Feb 2009 14:37:47 -0800
   4 Subject: fcoe: fix handling of pending queue, prevent out of order frames
   5 References: bnc#477953
   6
   7 The per-lport pending queue handling can result in a frame being retried
   8 from a different CPU than it was originally sent from.  The scope of the
   9 queue lock is not large enough to prevent reordering of frames within a
  10 sequence in that case.
  11
  12 Before this change I would see out of order frames on large write IOs,
  13 leading to frequent exchange timeouts and retries.
  14
  15 With the locking scope changed, the fcoe_insert_wait_queue(_head) helpers
  16 no longer do anything useful, so I removed them as well.
  17
  18 Signed-off-by: Chris Leech <christopher.leech@intel.com>
  19 Signed-off-by: Hannes Reinecke <hare@suse.de>
  20 ---
  21  drivers/scsi/fcoe/libfcoe.c |   64 +++++++++----------------------------------
  22  1 files changed, 13 insertions(+), 51 deletions(-)
  23
  24 diff --git a/drivers/scsi/fcoe/libfcoe.c b/drivers/scsi/fcoe/libfcoe.c
  25 index ada3ebb..d3f4eb9 100644
  26 --- a/drivers/scsi/fcoe/libfcoe.c
  27 +++ b/drivers/scsi/fcoe/libfcoe.c
  28 @@ -71,8 +71,6 @@ struct fcoe_percpu_s *fcoe_percpu[NR_CPUS];
  29
  30  /* Function Prototyes */
  31  static int fcoe_check_wait_queue(struct fc_lport *);
  32 -static void fcoe_insert_wait_queue_head(struct fc_lport *, struct sk_buff *);
  33 -static void fcoe_insert_wait_queue(struct fc_lport *, struct sk_buff *);
  34  static void fcoe_recv_flogi(struct fcoe_softc *, struct fc_frame *, u8 *);
  35  #ifdef CONFIG_HOTPLUG_CPU
  36  static int fcoe_cpu_callback(struct notifier_block *, ulong, void *);
  37 @@ -497,6 +495,7 @@ int fcoe_xmit(struct fc_lport *lp, struct fc_frame *fp)
  38
  39         /* send down to lld */
  40         fr_dev(fp) = lp;
  41 +       spin_lock_bh(&fc->fcoe_pending_queue.lock);
  42         if (fc->fcoe_pending_queue.qlen)
  43                 rc = fcoe_check_wait_queue(lp);
  44
  45 @@ -504,10 +503,11 @@ int fcoe_xmit(struct fc_lport *lp, struct fc_frame *fp)
  46                 rc = fcoe_start_io(skb);
  47
  48         if (rc) {
  49 -               fcoe_insert_wait_queue(lp, skb);
  50 +               __skb_queue_tail(&fc->fcoe_pending_queue, skb);
  51                 if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH)
  52                         lp->qfull = 1;
  53         }
  54 +       spin_unlock_bh(&fc->fcoe_pending_queue.lock);
  55
  56         return 0;
  57  }
  58 @@ -732,8 +732,11 @@ void fcoe_watchdog(ulong vp)
  59
  60         read_lock(&fcoe_hostlist_lock);
  61         list_for_each_entry(fc, &fcoe_hostlist, list) {
  62 -               if (fc->lp)
  63 +               if (fc->lp) {
  64 +                       spin_lock_bh(&fc->fcoe_pending_queue.lock);
  65                         fcoe_check_wait_queue(fc->lp);
  66 +                       spin_unlock_bh(&fc->fcoe_pending_queue.lock);
  67 +               }
  68         }
  69         read_unlock(&fcoe_hostlist_lock);
  70
  71 @@ -756,6 +759,8 @@ void fcoe_watchdog(ulong vp)
  72   * in the wait_queue which will be emptied by the time function OR
  73   * by the next skb transmit.
  74   *
  75 + * Locking: fc->fcoe_pending_queue.lock must be held before calling
  76 + *
  77   * Returns: 0 for success
  78   **/
  79  static int fcoe_check_wait_queue(struct fc_lport *lp)
  80 @@ -765,20 +770,17 @@ static int fcoe_check_wait_queue(struct fc_lport *lp)
  81         int rc = -1;
  82
  83         fc = fcoe_softc(lp);
  84 -       spin_lock_bh(&fc->fcoe_pending_queue.lock);
  85
  86         if (fc->fcoe_pending_queue_active)
  87                 goto out;
  88         fc->fcoe_pending_queue_active = 1;
  89         if (fc->fcoe_pending_queue.qlen) {
  90                 while ((skb = __skb_dequeue(&fc->fcoe_pending_queue)) != NULL) {
  91 -                       spin_unlock_bh(&fc->fcoe_pending_queue.lock);
  92                         rc = fcoe_start_io(skb);
  93 -                       if (rc)
  94 -                               fcoe_insert_wait_queue_head(lp, skb);
  95 -                       spin_lock_bh(&fc->fcoe_pending_queue.lock);
  96 -                       if (rc)
  97 +                       if (rc) {
  98 +                               __skb_queue_head(&fc->fcoe_pending_queue, skb);
  99                                 break;
 100 +                       }
 101                 }
 102                 /*
 103                  * if interface pending queue is below FCOE_LOW_QUEUE_DEPTH
 104 @@ -790,47 +792,10 @@ static int fcoe_check_wait_queue(struct fc_lport *lp)
 105         fc->fcoe_pending_queue_active = 0;
 106         rc = fc->fcoe_pending_queue.qlen;
 107  out:
 108 -       spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 109         return rc;
 110  }
 111
 112  /**
 113 - * fcoe_insert_wait_queue_head - puts skb to fcoe pending queue head
 114 - * @lp: the fc_port for this skb
 115 - * @skb: the associated skb to be xmitted
 116 - *
 117 - * Returns: none
 118 - **/
 119 -static void fcoe_insert_wait_queue_head(struct fc_lport *lp,
 120 -                                       struct sk_buff *skb)
 121 -{
 122 -       struct fcoe_softc *fc;
 123 -
 124 -       fc = fcoe_softc(lp);
 125 -       spin_lock_bh(&fc->fcoe_pending_queue.lock);
 126 -       __skb_queue_head(&fc->fcoe_pending_queue, skb);
 127 -       spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 128 -}
 129 -
 130 -/**
 131 - * fcoe_insert_wait_queue - put the skb into fcoe pending queue tail
 132 - * @lp: the fc_port for this skb
 133 - * @skb: the associated skb to be xmitted
 134 - *
 135 - * Returns: none
 136 - **/
 137 -static void fcoe_insert_wait_queue(struct fc_lport *lp,
 138 -                                  struct sk_buff *skb)
 139 -{
 140 -       struct fcoe_softc *fc;
 141 -
 142 -       fc = fcoe_softc(lp);
 143 -       spin_lock_bh(&fc->fcoe_pending_queue.lock);
 144 -       __skb_queue_tail(&fc->fcoe_pending_queue, skb);
 145 -       spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 146 -}
 147 -
 148 -/**
 149   * fcoe_dev_setup - setup link change notification interface
 150   *
 151   **/
 152 @@ -1187,11 +1152,8 @@ void fcoe_clean_pending_queue(struct fc_lport *lp)
 153         struct sk_buff *skb;
 154
 155         spin_lock_bh(&fc->fcoe_pending_queue.lock);
 156 -       while ((skb = __skb_dequeue(&fc->fcoe_pending_queue)) != NULL) {
 157 -               spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 158 +       while ((skb = __skb_dequeue(&fc->fcoe_pending_queue)) != NULL)
 159                 kfree_skb(skb);
 160 -               spin_lock_bh(&fc->fcoe_pending_queue.lock);
 161 -       }
 162         spin_unlock_bh(&fc->fcoe_pending_queue.lock);
 163  }
 164  EXPORT_SYMBOL_GPL(fcoe_clean_pending_queue);
 165 --
 166 1.5.4.5
 167