[libata] REQUEST SENSE handling fixes

- Move ATAPI check-condition handling out of the timeout handler
- Use multi-qc-issue feature to issue REQUEST SENSE ATAPI PACKET
  command upon receiving an ATAPI check-condition.

This cleans things up a lot, and eliminates a nasty recursion bug.

1 files changed, 43 insertions, 34 deletions

diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 0df4b682965d..3b4ca55a3332 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -1955,22 +1955,44 @@ void ata_scsi_badcmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *), u8
         done(cmd);
 }
 
-void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
-                         struct scsi_cmnd *cmd)
+static int atapi_sense_complete(struct ata_queued_cmd *qc,unsigned int err_mask)
 {
-        DECLARE_COMPLETION(wait);
-        struct ata_queued_cmd *qc;
-        unsigned long flags;
-        int rc;
+        if (err_mask && ((err_mask & AC_ERR_DEV) == 0))
+                /* FIXME: not quite right; we don't want the
+                 * translation of taskfile registers into
+                 * a sense descriptors, since that's only
+                 * correct for ATA, not ATAPI
+                 */
+                ata_gen_ata_desc_sense(qc);
 
-        DPRINTK("ATAPI request sense\n");
+        qc->scsidone(qc->scsicmd);
+        return 0;
+}
 
-        qc = ata_qc_new_init(ap, dev);
-        BUG_ON(qc == NULL);
+/* is it pointless to prefer PIO for "safety reasons"? */
+static inline int ata_pio_use_silly(struct ata_port *ap)
+{
+        return (ap->flags & ATA_FLAG_PIO_DMA);
+}
+
+static void atapi_request_sense(struct ata_queued_cmd *qc)
+{
+        struct ata_port *ap = qc->ap;
+        struct scsi_cmnd *cmd = qc->scsicmd;
+
+        DPRINTK("ATAPI request sense\n");
 
         /* FIXME: is this needed? */
         memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
 
+        ap->ops->tf_read(ap, &qc->tf);
+
+        /* fill these in, for the case where they are -not- overwritten */
+        cmd->sense_buffer[0] = 0x70;
+        cmd->sense_buffer[2] = qc->tf.feature >> 4;
+
+        ata_qc_reinit(qc);
+
         ata_sg_init_one(qc, cmd->sense_buffer, sizeof(cmd->sense_buffer));
         qc->dma_dir = DMA_FROM_DEVICE;
 
@@ -1981,22 +2003,20 @@ void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
         qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
         qc->tf.command = ATA_CMD_PACKET;
 
-        qc->tf.protocol = ATA_PROT_ATAPI;
-        qc->tf.lbam = (8 * 1024) & 0xff;
-        qc->tf.lbah = (8 * 1024) >> 8;
+        if (ata_pio_use_silly(ap)) {
+                qc->tf.protocol = ATA_PROT_ATAPI_DMA;
+                qc->tf.feature |= ATAPI_PKT_DMA;
+        } else {
+                qc->tf.protocol = ATA_PROT_ATAPI;
+                qc->tf.lbam = (8 * 1024) & 0xff;
+                qc->tf.lbah = (8 * 1024) >> 8;
+        }
         qc->nbytes = SCSI_SENSE_BUFFERSIZE;
 
-        qc->waiting = &wait;
-        qc->complete_fn = ata_qc_complete_noop;
+        qc->complete_fn = atapi_sense_complete;
 
-        spin_lock_irqsave(&ap->host_set->lock, flags);
-        rc = ata_qc_issue(qc);
-        spin_unlock_irqrestore(&ap->host_set->lock, flags);
-
-        if (rc)
-                ata_port_disable(ap);
-        else
-                wait_for_completion(&wait);
+        if (ata_qc_issue(qc))
+                ata_qc_complete(qc, AC_ERR_OTHER);
 
         DPRINTK("EXIT\n");
 }
@@ -2008,19 +2028,8 @@ static int atapi_qc_complete(struct ata_queued_cmd *qc, unsigned int err_mask)
         VPRINTK("ENTER, err_mask 0x%X\n", err_mask);
 
         if (unlikely(err_mask & AC_ERR_DEV)) {
-                DPRINTK("request check condition\n");
-
-                /* FIXME: command completion with check condition
-                 * but no sense causes the error handler to run,
-                 * which then issues REQUEST SENSE, fills in the sense 
-                 * buffer, and completes the command (for the second
-                 * time).  We need to issue REQUEST SENSE some other
-                 * way, to avoid completing the command twice.
-                 */
                 cmd->result = SAM_STAT_CHECK_CONDITION;
-
-                qc->scsidone(cmd);
-
+                atapi_request_sense(qc);
                 return 1;
         }