[PATCH] libata-ncq: pass ata_scsi_translate() return value to SCSI midlayer

ata_scsi_translate() will need to return SCSI_ML_QUEUE_DEVICE_BUSY to
achieve exlusion between NCQ and non-NCQ commands or among non-NCQ
commands.  Pass its return value upward to SCSI midlayer.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 24 insertions, 16 deletions

diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index e61cc357ae4a..96517ca021e3 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -1248,11 +1248,14 @@ static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
  *
  *      LOCKING:
  *      spin_lock_irqsave(host_set lock)
+ *
+ *      RETURNS:
+ *      0 on success, SCSI_ML_QUEUE_DEVICE_BUSY if the command
+ *      needs to be deferred.
  */
-
-static void ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
-                               void (*done)(struct scsi_cmnd *),
-                               ata_xlat_func_t xlat_func)
+static int ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
+                              void (*done)(struct scsi_cmnd *),
+                              ata_xlat_func_t xlat_func)
 {
         struct ata_queued_cmd *qc;
         u8 *scsicmd = cmd->cmnd;
@@ -1290,13 +1293,13 @@ static void ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
         ata_qc_issue(qc);
 
         VPRINTK("EXIT\n");
-        return;
+        return 0;
 
 early_finish:
         ata_qc_free(qc);
         done(cmd);
         DPRINTK("EXIT - early finish (good or error)\n");
-        return;
+        return 0;
 
 err_did:
         ata_qc_free(qc);
@@ -1304,7 +1307,7 @@ err_mem:
         cmd->result = (DID_ERROR << 16);
         done(cmd);
         DPRINTK("EXIT - internal\n");
-        return;
+        return 0;
 }
 
 /**
@@ -2456,20 +2459,24 @@ static inline void ata_scsi_dump_cdb(struct ata_port *ap,
 #endif
 }
 
-static inline void __ata_scsi_queuecmd(struct scsi_cmnd *cmd,
-                                       void (*done)(struct scsi_cmnd *),
-                                       struct ata_device *dev)
+static inline int __ata_scsi_queuecmd(struct scsi_cmnd *cmd,
+                                      void (*done)(struct scsi_cmnd *),
+                                      struct ata_device *dev)
 {
+        int rc = 0;
+
         if (dev->class == ATA_DEV_ATA) {
                 ata_xlat_func_t xlat_func = ata_get_xlat_func(dev,
                                                               cmd->cmnd[0]);
 
                 if (xlat_func)
-                        ata_scsi_translate(dev, cmd, done, xlat_func);
+                        rc = ata_scsi_translate(dev, cmd, done, xlat_func);
                 else
                         ata_scsi_simulate(dev, cmd, done);
         } else
-                ata_scsi_translate(dev, cmd, done, atapi_xlat);
+                rc = ata_scsi_translate(dev, cmd, done, atapi_xlat);
+
+        return rc;
 }
 
 /**
@@ -2488,15 +2495,16 @@ static inline void __ata_scsi_queuecmd(struct scsi_cmnd *cmd,
  *      Releases scsi-layer-held lock, and obtains host_set lock.
  *
  *      RETURNS:
- *      Zero.
+ *      Return value from __ata_scsi_queuecmd() if @cmd can be queued,
+ *      0 otherwise.
  */
-
 int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
 {
         struct ata_port *ap;
         struct ata_device *dev;
         struct scsi_device *scsidev = cmd->device;
         struct Scsi_Host *shost = scsidev->host;
+        int rc = 0;
 
         ap = ata_shost_to_port(shost);
 
@@ -2507,7 +2515,7 @@ int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
 
         dev = ata_scsi_find_dev(ap, scsidev);
         if (likely(dev))
-                __ata_scsi_queuecmd(cmd, done, dev);
+                rc = __ata_scsi_queuecmd(cmd, done, dev);
         else {
                 cmd->result = (DID_BAD_TARGET << 16);
                 done(cmd);
@@ -2515,7 +2523,7 @@ int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
 
         spin_unlock(&ap->host_set->lock);
         spin_lock(shost->host_lock);
-        return 0;
+        return rc;
 }
 
 /**