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authorGwendal Grignou <gwendal@google.com>2009-10-12 18:44:00 -0400
committerJeff Garzik <jgarzik@redhat.com>2009-10-16 06:22:46 -0400
commit159a7ff7a13f9a02c75006f40c0561a3a81aefcd (patch)
tree54171cdbd746ea9d5a2efaa87639b14b54dc5034 /drivers/ata/sata_mv.c
parent6d4f950e9ea15816c6a4f266ce6b9e438346771e (diff)
sata_mv: Prevent PIO commands to be defered too long if traffic in progress.
Use excl_link when non NCQ commands are defered, to be sure they are processed as soon as outstanding commands are completed. It prevents some commands to be defered indifinitely when using a port multiplier. Signed-off-by: Gwendal Grignou <gwendal@google.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers/ata/sata_mv.c')
-rw-r--r--drivers/ata/sata_mv.c29
1 files changed, 27 insertions, 2 deletions
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 17f9ff9067a2..6f5093b7c8c5 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -1382,6 +1382,25 @@ static int mv_qc_defer(struct ata_queued_cmd *qc)
1382 */ 1382 */
1383 if (pp->pp_flags & MV_PP_FLAG_DELAYED_EH) 1383 if (pp->pp_flags & MV_PP_FLAG_DELAYED_EH)
1384 return ATA_DEFER_PORT; 1384 return ATA_DEFER_PORT;
1385
1386 /* PIO commands need exclusive link: no other commands [DMA or PIO]
1387 * can run concurrently.
1388 * set excl_link when we want to send a PIO command in DMA mode
1389 * or a non-NCQ command in NCQ mode.
1390 * When we receive a command from that link, and there are no
1391 * outstanding commands, mark a flag to clear excl_link and let
1392 * the command go through.
1393 */
1394 if (unlikely(ap->excl_link)) {
1395 if (link == ap->excl_link) {
1396 if (ap->nr_active_links)
1397 return ATA_DEFER_PORT;
1398 qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
1399 return 0;
1400 } else
1401 return ATA_DEFER_PORT;
1402 }
1403
1385 /* 1404 /*
1386 * If the port is completely idle, then allow the new qc. 1405 * If the port is completely idle, then allow the new qc.
1387 */ 1406 */
@@ -1395,8 +1414,14 @@ static int mv_qc_defer(struct ata_queued_cmd *qc)
1395 * doesn't allow it. 1414 * doesn't allow it.
1396 */ 1415 */
1397 if ((pp->pp_flags & MV_PP_FLAG_EDMA_EN) && 1416 if ((pp->pp_flags & MV_PP_FLAG_EDMA_EN) &&
1398 (pp->pp_flags & MV_PP_FLAG_NCQ_EN) && ata_is_ncq(qc->tf.protocol)) 1417 (pp->pp_flags & MV_PP_FLAG_NCQ_EN)) {
1399 return 0; 1418 if (ata_is_ncq(qc->tf.protocol))
1419 return 0;
1420 else {
1421 ap->excl_link = link;
1422 return ATA_DEFER_PORT;
1423 }
1424 }
1400 1425
1401 return ATA_DEFER_PORT; 1426 return ATA_DEFER_PORT;
1402} 1427}