[PATCH] cleanup device_busy/host_busy handling

- scsi_host_busy_inc isn't used anymore (and uses broken locking rules),
  kill it.
- scsi_host_busy_dec_and_test gets replace by scsi_device_unbusy that
  also cares for sdev->device_busty.
- there's a new helper, scsi_eh_wakeup, shared by scsi_device_unbusy
  and some EH code.

drivers/scsi/hosts.c

@@ -289,29 +289,3 @@ void scsi_host_put(struct Scsi_Host *shost)
 	class_device_put(&shost->class_dev);
 	put_device(&shost->host_gendev);
 }
-
-void scsi_host_busy_inc(struct Scsi_Host *shost, Scsi_Device *sdev)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(shost->host_lock, flags);
-	shost->host_busy++;
-	sdev->device_busy++;
-	spin_unlock_irqrestore(shost->host_lock, flags);
-}
-
-void scsi_host_busy_dec_and_test(struct Scsi_Host *shost, Scsi_Device *sdev)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(shost->host_lock, flags);
-	shost->host_busy--;
-	if (shost->in_recovery && shost->host_failed &&
-	    (shost->host_busy == shost->host_failed))
-	{
-		up(shost->eh_wait);
-		SCSI_LOG_ERROR_RECOVERY(5, printk("Waking error handler"
-					  " thread\n"));
-	}
-	spin_unlock_irqrestore(shost->host_lock, flags);
-}

drivers/scsi/scsi.c

@@ -733,16 +733,8 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
 	struct scsi_device *sdev = cmd->device;
 	struct Scsi_Host *shost = sdev->host;
 	struct scsi_request *sreq;
-	unsigned long flags;
-
-	scsi_host_busy_dec_and_test(shost, sdev);
 
-	/*
-	 * XXX(hch): We really want a nice helper for this..
-	 */
-	spin_lock_irqsave(&sdev->sdev_lock, flags);
-	sdev->device_busy--;
-	spin_unlock_irqrestore(&sdev->sdev_lock, flags);
+	scsi_device_unbusy(sdev);
 
         /*
          * Clear the flags which say that the device/host is no longer

drivers/scsi/scsi_error.c

@@ -44,6 +44,16 @@
 #define BUS_RESET_SETTLE_TIME   10*HZ
 #define HOST_RESET_SETTLE_TIME  10*HZ
 
+/* called with shost->host_lock held */
+void scsi_eh_wakeup(struct Scsi_Host *shost)
+{
+	if (shost->host_busy == shost->host_failed) {
+		up(shost->eh_wait);
+		SCSI_LOG_ERROR_RECOVERY(5,
+				printk("Waking error handler thread\n"));
+	}
+}
+
 /**
  * scsi_eh_scmd_add - add scsi cmd to error handling.
  * @scmd:	scmd to run eh on.
@@ -76,14 +86,8 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
 	list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 	shost->in_recovery = 1;
 	shost->host_failed++;
-	if (shost->host_busy == shost->host_failed) {
-		up(shost->eh_wait);
-		SCSI_LOG_ERROR_RECOVERY(5, printk("Waking error handler"
-					  " thread\n"));
-	}
-
+	scsi_eh_wakeup(shost);
 	spin_unlock_irqrestore(shost->host_lock, flags);
-
 	return 1;
 }
 

drivers/scsi/scsi_lib.c

@@ -95,7 +95,6 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 {
 	struct Scsi_Host *host = cmd->device->host;
 	struct scsi_device *device = cmd->device;
-	unsigned long flags;
 
 	SCSI_LOG_MLQUEUE(1,
 		 printk("Inserting command %p into mlqueue\n", cmd));
@@ -134,10 +133,7 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 	 * Decrement the counters, since these commands are no longer
 	 * active on the host/device.
 	 */
-	spin_lock_irqsave(device->request_queue->queue_lock, flags);
-	device->device_busy--;
-	spin_unlock_irqrestore(device->request_queue->queue_lock, flags);
-	scsi_host_busy_dec_and_test(host, device);
+	scsi_device_unbusy(device);
 
 	/*
 	 * Insert this command at the head of the queue for it's device.
@@ -314,6 +310,21 @@ void scsi_setup_cmd_retry(struct scsi_cmnd *cmd)
 	cmd->underflow = cmd->old_underflow;
 }
 
+void scsi_device_unbusy(struct scsi_device *sdev)
+{
+	struct Scsi_Host *shost = sdev->host;
+	unsigned long flags;
+
+	spin_lock_irqsave(shost->host_lock, flags);
+	shost->host_busy--;
+	if (unlikely(shost->in_recovery && shost->host_failed))
+		scsi_eh_wakeup(shost);
+	spin_unlock(shost->host_lock);
+	spin_lock(&sdev->sdev_lock);
+	sdev->device_busy--;
+	spin_unlock_irqrestore(&sdev->sdev_lock, flags);
+}
+
 /*
  * Called for single_lun devices on IO completion. Clear starget_sdev_user,
  * and call blk_run_queue for all the scsi_devices on the target -

drivers/scsi/scsi_priv.h

@@ -52,10 +52,6 @@ struct scsi_target {
 };
 
 
-/* hosts.c */
-extern void scsi_host_busy_inc(struct Scsi_Host *, Scsi_Device *);
-extern void scsi_host_busy_dec_and_test(struct Scsi_Host *, Scsi_Device *);
-
 /* scsi.c */
 extern int scsi_dispatch_cmd(struct scsi_cmnd *cmd);
 extern int scsi_setup_command_freelist(struct Scsi_Host *shost);
@@ -77,11 +73,13 @@ extern void scsi_exit_devinfo(void);
 extern void scsi_times_out(struct scsi_cmnd *cmd);
 extern void scsi_error_handler(void *host);
 extern int scsi_decide_disposition(struct scsi_cmnd *cmd);
+extern void scsi_eh_wakeup(struct Scsi_Host *shost);
 extern int scsi_eh_scmd_add(struct scsi_cmnd *, int);
 
 /* scsi_lib.c */
 extern int scsi_maybe_unblock_host(struct scsi_device *sdev);
 extern void scsi_setup_cmd_retry(struct scsi_cmnd *cmd);
+extern void scsi_device_unbusy(struct scsi_device *sdev);
 extern int scsi_queue_insert(struct scsi_cmnd *cmd, int reason);
 extern void scsi_next_command(struct scsi_cmnd *cmd);
 extern void scsi_run_host_queues(struct Scsi_Host *shost);