[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_sx4.c b/drivers/scsi/sata_sx4.c
index bc87c16..3175c6b 100644
--- a/drivers/scsi/sata_sx4.c
+++ b/drivers/scsi/sata_sx4.c
@@ -174,7 +174,7 @@
 static void pdc20621_put_to_dimm(struct ata_probe_ent *pe,
 				 void *psource, u32 offset, u32 size);
 static void pdc20621_irq_clear(struct ata_port *ap);
-static int pdc20621_qc_issue_prot(struct ata_queued_cmd *qc);
+static unsigned int pdc20621_qc_issue_prot(struct ata_queued_cmd *qc);
 
 
 static struct scsi_host_template pdc_sata_sht = {
@@ -678,7 +678,7 @@
 	}
 }
 
-static int pdc20621_qc_issue_prot(struct ata_queued_cmd *qc)
+static unsigned int pdc20621_qc_issue_prot(struct ata_queued_cmd *qc)
 {
 	switch (qc->tf.protocol) {
 	case ATA_PROT_DMA: