src/patches/suse-2.6.27.25/patches.fixes/scsi-terminate-target-reset

   1 From: James Bottomley <James.Bottomley@HansenPartnership.com>
   2 Subject: Target reset hangs
   3 Date: Fri, 12 Sep 2008 16:46:51 -0500
   4 References: bnc#427267
   5
   6 Actually, turns out it's nothing to do with block timeouts, it's a
   7 target reset bug.
   8
   9 This loop:
  10
  11         for (id = 0; id <= shost->max_id; id++) {
  12
  13 Never terminates if shost->max_id is set to ~0, like aic94xx does.
  14
  15 It's also pretty inefficient since you mostly have compact target
  16 numbers, but the max_id can be very high.  The best way would be to sort
  17 the recovery list by target id and skip them if they're equal, but even
  18 a worst case O(N^2) traversal is probably OK here.
  19
  20 Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
  21 Signed-off-by: Hannes Reinecke <hare@suse.de>
  22 ---
  23 diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
  24 index ad019ec..94ed262 100644
  25 --- a/drivers/scsi/scsi_error.c
  26 +++ b/drivers/scsi/scsi_error.c
  27 @@ -1065,10 +1065,10 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
  28                                 struct list_head *done_q)
  29  {
  30         struct scsi_cmnd *scmd, *tgtr_scmd, *next;
  31 -       unsigned int id;
  32 +       unsigned int id = 0;
  33         int rtn;
  34
  35 -       for (id = 0; id <= shost->max_id; id++) {
  36 +       do {
  37                 tgtr_scmd = NULL;
  38                 list_for_each_entry(scmd, work_q, eh_entry) {
  39                         if (id == scmd_id(scmd)) {
  40 @@ -1076,8 +1076,18 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
  41                                 break;
  42                         }
  43                 }
  44 +               if (!tgtr_scmd) {
  45 +                       /* not one exactly equal; find the next highest */
  46 +                       list_for_each_entry(scmd, work_q, eh_entry) {
  47 +                               if (scmd_id(scmd) > id &&
  48 +                                   (!tgtr_scmd ||
  49 +                                    scmd_id(tgtr_scmd) > scmd_id(scmd)))
  50 +                                               tgtr_scmd = scmd;
  51 +                       }
  52 +               }
  53                 if (!tgtr_scmd)
  54 -                       continue;
  55 +                       /* no more commands, that's it */
  56 +                       break;
  57
  58                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
  59                                                   "to target %d\n",
  60 @@ -1096,7 +1106,8 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
  61                                                           " failed target: "
  62                                                           "%d\n",
  63                                                           current->comm, id));
  64 -       }
  65 +               id++;
  66 +       } while(id != 0);
  67
  68         return list_empty(work_q);
  69  }
  70
  71
  72
  73
  74
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