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-rw-r--r--drivers/ata/libata-core.c21
-rw-r--r--include/linux/libata.h1
2 files changed, 14 insertions, 8 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index f2a6020366e1..73c5d0410d47 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4794,21 +4794,26 @@ 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;
}
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 1de36be64df4..5ab4e3a76721 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -822,6 +822,7 @@ struct ata_port {
unsigned long qc_allocated;
unsigned int qc_active;
int nr_active_links; /* #links with active qcs */
+ unsigned int last_tag; /* track next tag hw expects */
struct ata_link link; /* host default link */
struct ata_link *slave_link; /* see ata_slave_link_init() */