libata-pmp-prep: implement ops->qc_defer()

[deliverable/linux.git] / drivers / ata / libata-scsi.c

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index dc274001ddd99289b4af6b0f6ef2322cffd44753..8ca2caeed01707a624cbf5ab5c13384252ed99e9 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -749,6 +749,13 @@ static void ata_scsi_sdev_config(struct scsi_device *sdev)
 {
        sdev->use_10_for_rw = 1;
        sdev->use_10_for_ms = 1;
+
+       /* Schedule policy is determined by ->qc_defer() callback and
+        * it needs to see every deferred qc.  Set dev_blocked to 1 to
+        * prevent SCSI midlayer from automatically deferring
+        * requests.
+        */
+       sdev->max_device_blocked = 1;
 }
 
 static void ata_scsi_dev_config(struct scsi_device *sdev,
@@ -1415,37 +1422,6 @@ static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
        ata_qc_free(qc);
 }
 
-/**
- *     ata_scmd_need_defer - Check whether we need to defer scmd
- *     @dev: ATA device to which the command is addressed
- *     @is_io: Is the command IO (and thus possibly NCQ)?
- *
- *     NCQ and non-NCQ commands cannot run together.  As upper layer
- *     only knows the queue depth, we are responsible for maintaining
- *     exclusion.  This function checks whether a new command can be
- *     issued to @dev.
- *
- *     LOCKING:
- *     spin_lock_irqsave(host lock)
- *
- *     RETURNS:
- *     1 if deferring is needed, 0 otherwise.
- */
-static int ata_scmd_need_defer(struct ata_device *dev, int is_io)
-{
-       struct ata_link *link = dev->link;
-       int is_ncq = is_io && ata_ncq_enabled(dev);
-
-       if (is_ncq) {
-               if (!ata_tag_valid(link->active_tag))
-                       return 0;
-       } else {
-               if (!ata_tag_valid(link->active_tag) && !link->sactive)
-                       return 0;
-       }
-       return 1;
-}
-
 /**
  *     ata_scsi_translate - Translate then issue SCSI command to ATA device
  *     @dev: ATA device to which the command is addressed
@@ -1477,14 +1453,12 @@ 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_port *ap = dev->link->ap;
        struct ata_queued_cmd *qc;
-       int is_io = xlat_func == ata_scsi_rw_xlat;
+       int rc;
 
        VPRINTK("ENTER\n");
 
-       if (unlikely(ata_scmd_need_defer(dev, is_io)))
-               goto defer;
-
        qc = ata_scsi_qc_new(dev, cmd, done);
        if (!qc)
                goto err_mem;
@@ -1508,6 +1482,11 @@ static int ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
        if (xlat_func(qc))
                goto early_finish;
 
+       if (ap->ops->qc_defer) {
+               if ((rc = ap->ops->qc_defer(qc)))
+                       goto defer;
+       }
+
        /* select device, send command to hardware */
        ata_qc_issue(qc);
 
@@ -1529,8 +1508,12 @@ err_mem:
        return 0;
 
 defer:
+       ata_qc_free(qc);
        DPRINTK("EXIT - defer\n");
-       return SCSI_MLQUEUE_DEVICE_BUSY;
+       if (rc == ATA_DEFER_LINK)
+               return SCSI_MLQUEUE_DEVICE_BUSY;
+       else
+               return SCSI_MLQUEUE_HOST_BUSY;
 }
 
 /**
@@ -3034,6 +3017,13 @@ int ata_scsi_add_hosts(struct ata_host *host, struct scsi_host_template *sht)
                shost->max_channel = 1;
                shost->max_cmd_len = 16;
 
+               /* Schedule policy is determined by ->qc_defer()
+                * callback and it needs to see every deferred qc.
+                * Set host_blocked to 1 to prevent SCSI midlayer from
+                * automatically deferring requests.
+                */
+               shost->max_host_blocked = 1;
+
                rc = scsi_add_host(ap->scsi_host, ap->host->dev);
                if (rc)
                        goto err_add;