src/patches/suse-2.6.27.25/patches.fixes/scsi-refactor-busy-processing

   1 Subject: [SCSI] refactor sdev/starget/shost busy checking
   2 From: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
   3 Date: Thu Oct 23 11:42:16 2008 -0500:
   4 Git: 9d11251709f31d49c8167a619d4475fdf6cd7f73
   5
   6 This patch refactors the busy checking codes of scsi_device,
   7 Scsi_Host and scsi_target.  There should be no functional change.
   8
   9 This is a preparation for another patch which exports scsi's busy
  10 state to the block layer for request stacking drivers.
  11
  12 Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
  13 Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
  14 Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
  15 Signed-off-by: Hannes Reinecke <hare@suse.de>
  16
  17 ---
  18  drivers/scsi/scsi_lib.c |   30 ++++++++++++++++++++----------
  19  1 file changed, 20 insertions(+), 10 deletions(-)
  20
  21 --- a/drivers/scsi/scsi_lib.c
  22 +++ b/drivers/scsi/scsi_lib.c
  23 @@ -529,6 +529,14 @@ static void scsi_single_lun_run(struct s
  24         spin_unlock_irqrestore(shost->host_lock, flags);
  25  }
  26
  27 +static inline int scsi_device_is_busy(struct scsi_device *sdev)
  28 +{
  29 +       if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked)
  30 +               return 1;
  31 +
  32 +       return 0;
  33 +}
  34 +
  35  static inline int scsi_target_is_busy(struct scsi_target *starget)
  36  {
  37         return ((starget->can_queue > 0 &&
  38 @@ -536,6 +544,15 @@ static inline int scsi_target_is_busy(st
  39                  starget->target_blocked);
  40  }
  41
  42 +static inline int scsi_host_is_busy(struct Scsi_Host *shost)
  43 +{
  44 +       if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
  45 +           shost->host_blocked || shost->host_self_blocked)
  46 +               return 1;
  47 +
  48 +       return 0;
  49 +}
  50 +
  51  /*
  52   * Function:   scsi_run_queue()
  53   *
  54 @@ -558,11 +575,7 @@ static void scsi_run_queue(struct reques
  55                 scsi_single_lun_run(sdev);
  56
  57         spin_lock_irqsave(shost->host_lock, flags);
  58 -       while (!list_empty(&shost->starved_list) &&
  59 -              !shost->host_blocked && !shost->host_self_blocked &&
  60 -               !((shost->can_queue > 0) &&
  61 -                 (shost->host_busy >= shost->can_queue))) {
  62 -
  63 +       while (!list_empty(&shost->starved_list) && !scsi_host_is_busy(shost)) {
  64                 int flagset;
  65
  66                 /*
  67 @@ -1349,8 +1362,6 @@ EXPORT_SYMBOL(scsi_prep_fn);
  68  static inline int scsi_dev_queue_ready(struct request_queue *q,
  69                                   struct scsi_device *sdev)
  70  {
  71 -       if (sdev->device_busy >= sdev->queue_depth)
  72 -               return 0;
  73         if (sdev->device_busy == 0 && sdev->device_blocked) {
  74                 /*
  75                  * unblock after device_blocked iterates to zero
  76 @@ -1364,7 +1375,7 @@ static inline int scsi_dev_queue_ready(s
  77                         return 0;
  78                 }
  79         }
  80 -       if (sdev->device_blocked)
  81 +       if (scsi_device_is_busy(sdev))
  82                 return 0;
  83
  84         return 1;
  85 @@ -1441,8 +1452,7 @@ static inline int scsi_host_queue_ready(
  86                         return 0;
  87                 }
  88         }
  89 -       if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
  90 -           shost->host_blocked || shost->host_self_blocked) {
  91 +       if (scsi_host_is_busy(shost)) {
  92                 if (list_empty(&sdev->starved_entry))
  93                         list_add_tail(&sdev->starved_entry, &shost->starved_list);
  94                 return 0;