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path: root/drivers/ata/libata-core.c
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Diffstat (limited to 'drivers/ata/libata-core.c')
-rw-r--r--drivers/ata/libata-core.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 18d97d5c7d90..677c0c1b03bd 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4787,6 +4787,10 @@ 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.
*/
@@ -4794,14 +4798,15 @@ 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 max_queue = ap->host->n_tags;
unsigned int i, tag;
/* 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)
@@ -6088,6 +6093,7 @@ void ata_host_init(struct ata_host *host, struct device *dev,
{
spin_lock_init(&host->lock);
mutex_init(&host->eh_mutex);
+ host->n_tags = ATA_MAX_QUEUE - 1;
host->dev = dev;
host->ops = ops;
}
@@ -6169,6 +6175,8 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
{
int i, rc;
+ host->n_tags = clamp(sht->can_queue, 1, ATA_MAX_QUEUE - 1);
+
/* host must have been started */
if (!(host->flags & ATA_HOST_STARTED)) {
dev_err(host->dev, "BUG: trying to register unstarted host\n");