[PATCH] libata: make ata_set_mode() handle no-device case properly

Make ata_set_mode() return without doing anything if there is no
device on the port.  This is in preparation for ata_bus_probe()
changes.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index c10c550da38bf189ca2e0b2ba971bd7414d20703..913e378eca7fefe73260255e1b2b9a402150ca6a 100644 (file)
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1823,7 +1823,7 @@ static void ata_host_set_dma(struct ata_port *ap)
  */
 static void ata_set_mode(struct ata_port *ap)
 {
-       int i, rc, used_dma = 0;
+       int i, rc, used_dma = 0, found = 0;
 
        /* step 1: calculate xfer_mask */
        for (i = 0; i < ATA_MAX_DEVICES; i++) {
@@ -1842,9 +1842,12 @@ static void ata_set_mode(struct ata_port *ap)
                dev->pio_mode = ata_xfer_mask2mode(pio_mask);
                dev->dma_mode = ata_xfer_mask2mode(dma_mask);
 
+               found = 1;
                if (dev->dma_mode)
                        used_dma = 1;
        }
+       if (!found)
+               return;
 
        /* step 2: always set host PIO timings */
        rc = ata_host_set_pio(ap);