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authorKevin Hao <haokexin@gmail.com>2014-07-12 12:08:24 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-31 12:53:48 -0700
commit97a230703c9f6cbed3bdd4d4a627863c14a8a2de (patch)
tree5b3d8691096f8eb0188cab254fb6c6665cc2e51d /drivers/ata
parentcb454b6d31756674d2e0ceaa336ec87019728d9b (diff)
downloadlinux-linaro-stable-97a230703c9f6cbed3bdd4d4a627863c14a8a2de.tar.gz
libata: support the ata host which implements a queue depth less than 32
commit 1871ee134b73fb4cadab75752a7152ed2813c751 upstream. The sata on fsl mpc8315e is broken after the commit 8a4aeec8d2d6 ("libata/ahci: accommodate tag ordered controllers"). The reason is that the ata controller on this SoC only implement a queue depth of 16. When issuing the commands in tag order, all the commands in tag 16 ~ 31 are mapped to tag 0 unconditionally and then causes the sata malfunction. It makes no senses to use a 32 queue in software while the hardware has less queue depth. So consider the queue depth implemented by the hardware when requesting a command tag. Fixes: 8a4aeec8d2d6 ("libata/ahci: accommodate tag ordered controllers") Signed-off-by: Kevin Hao <haokexin@gmail.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/ata')
-rw-r--r--drivers/ata/libata-core.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index bf00fbcde8ad..d7fb8269cb73 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4758,6 +4758,10 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
* ata_qc_new - Request an available ATA command, for queueing
* @ap: target port
*
+ * Some ATA host controllers may implement a queue depth which is less
+ * than ATA_MAX_QUEUE. So we shouldn't allocate a tag which is beyond
+ * the hardware limitation.
+ *
* LOCKING:
* None.
*/
@@ -4765,14 +4769,16 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
{
struct ata_queued_cmd *qc = NULL;
- unsigned int i, tag;
+ unsigned int i, tag, max_queue;
+
+ max_queue = ap->scsi_host->can_queue;
/* no command while frozen */
if (unlikely(ap->pflags & ATA_PFLAG_FROZEN))
return NULL;
- for (i = 0; i < ATA_MAX_QUEUE; i++) {
- tag = (i + ap->last_tag + 1) % ATA_MAX_QUEUE;
+ for (i = 0, tag = ap->last_tag + 1; i < max_queue; i++, tag++) {
+ tag = tag < max_queue ? tag : 0;
/* the last tag is reserved for internal command. */
if (tag == ATA_TAG_INTERNAL)
@@ -6154,6 +6160,16 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
{
int i, rc;
+ /*
+ * The max queue supported by hardware must not be greater than
+ * ATA_MAX_QUEUE.
+ */
+ if (sht->can_queue > ATA_MAX_QUEUE) {
+ dev_err(host->dev, "BUG: the hardware max queue is too large\n");
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
/* host must have been started */
if (!(host->flags & ATA_HOST_STARTED)) {
dev_err(host->dev, "BUG: trying to register unstarted host\n");