diff options
Diffstat (limited to 'drivers/ata/libata-core.c')
| -rw-r--r-- | drivers/ata/libata-core.c | 12 |
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"); |