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-rw-r--r--drivers/ata/libata-core.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 8b8cbe9bcb92..9cf616b5210b 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4765,21 +4765,26 @@ 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;
+ unsigned int i, tag;
/* no command while frozen */
if (unlikely(ap->pflags & ATA_PFLAG_FROZEN))
return NULL;
- /* the last tag is reserved for internal command. */
- for (i = 0; i < ATA_MAX_QUEUE - 1; i++)
- if (!test_and_set_bit(i, &ap->qc_allocated)) {
- qc = __ata_qc_from_tag(ap, i);
+ for (i = 0; i < ATA_MAX_QUEUE; i++) {
+ tag = (i + ap->last_tag + 1) % ATA_MAX_QUEUE;
+
+ /* the last tag is reserved for internal command. */
+ if (tag == ATA_TAG_INTERNAL)
+ continue;
+
+ if (!test_and_set_bit(tag, &ap->qc_allocated)) {
+ qc = __ata_qc_from_tag(ap, tag);
+ qc->tag = tag;
+ ap->last_tag = tag;
break;
}
-
- if (qc)
- qc->tag = i;
+ }
return qc;
}