[PATCH] libata: return AC_ERR_* from issue functions

Return AC_ERR_* mask from issue fuctions instead of 0/-1.  This
enables things like failing a qc with AC_ERR_HSM when the device
doesn't set DRDY when the qc is about to be issued.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/scsi/sata_mv.c b/drivers/scsi/sata_mv.c
index 89bcd85..281223a 100644
--- a/drivers/scsi/sata_mv.c
+++ b/drivers/scsi/sata_mv.c
@@ -328,7 +328,7 @@
 static int mv_port_start(struct ata_port *ap);
 static void mv_port_stop(struct ata_port *ap);
 static void mv_qc_prep(struct ata_queued_cmd *qc);
-static int mv_qc_issue(struct ata_queued_cmd *qc);
+static unsigned int mv_qc_issue(struct ata_queued_cmd *qc);
 static irqreturn_t mv_interrupt(int irq, void *dev_instance,
 				struct pt_regs *regs);
 static void mv_eng_timeout(struct ata_port *ap);
@@ -1040,7 +1040,7 @@
  *      LOCKING:
  *      Inherited from caller.
  */
-static int mv_qc_issue(struct ata_queued_cmd *qc)
+static unsigned int mv_qc_issue(struct ata_queued_cmd *qc)
 {
 	void __iomem *port_mmio = mv_ap_base(qc->ap);
 	struct mv_port_priv *pp = qc->ap->private_data;