[SCSI] refactor sdev/starget/shost busy checking
Kiyoshi Ueda [Sat, 4 Oct 2008 18:11:06 +0000 (14:11 -0400)]
This patch refactors the busy checking codes of scsi_device,
Scsi_Host and scsi_target.  There should be no functional change.

This is a preparation for another patch which exports scsi's busy
state to the block layer for request stacking drivers.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/scsi_lib.c

index f35a095..1e7c9e9 100644 (file)
@@ -529,6 +529,14 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev)
        spin_unlock_irqrestore(shost->host_lock, flags);
 }
 
+static inline int scsi_device_is_busy(struct scsi_device *sdev)
+{
+       if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked)
+               return 1;
+
+       return 0;
+}
+
 static inline int scsi_target_is_busy(struct scsi_target *starget)
 {
        return ((starget->can_queue > 0 &&
@@ -536,6 +544,15 @@ static inline int scsi_target_is_busy(struct scsi_target *starget)
                 starget->target_blocked);
 }
 
+static inline int scsi_host_is_busy(struct Scsi_Host *shost)
+{
+       if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
+           shost->host_blocked || shost->host_self_blocked)
+               return 1;
+
+       return 0;
+}
+
 /*
  * Function:   scsi_run_queue()
  *
@@ -558,11 +575,7 @@ static void scsi_run_queue(struct request_queue *q)
                scsi_single_lun_run(sdev);
 
        spin_lock_irqsave(shost->host_lock, flags);
-       while (!list_empty(&shost->starved_list) &&
-              !shost->host_blocked && !shost->host_self_blocked &&
-               !((shost->can_queue > 0) &&
-                 (shost->host_busy >= shost->can_queue))) {
-
+       while (!list_empty(&shost->starved_list) && !scsi_host_is_busy(shost)) {
                int flagset;
 
                /*
@@ -1348,8 +1361,6 @@ int scsi_prep_fn(struct request_queue *q, struct request *req)
 static inline int scsi_dev_queue_ready(struct request_queue *q,
                                  struct scsi_device *sdev)
 {
-       if (sdev->device_busy >= sdev->queue_depth)
-               return 0;
        if (sdev->device_busy == 0 && sdev->device_blocked) {
                /*
                 * unblock after device_blocked iterates to zero
@@ -1363,7 +1374,7 @@ static inline int scsi_dev_queue_ready(struct request_queue *q,
                        return 0;
                }
        }
-       if (sdev->device_blocked)
+       if (scsi_device_is_busy(sdev))
                return 0;
 
        return 1;
@@ -1440,8 +1451,7 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
                        return 0;
                }
        }
-       if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
-           shost->host_blocked || shost->host_self_blocked) {
+       if (scsi_host_is_busy(shost)) {
                if (list_empty(&sdev->starved_entry))
                        list_add_tail(&sdev->starved_entry, &shost->starved_list);
                return 0;