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[v2,1/2] libata: introduce ata_host_set_queue_depth()

Message ID 20140708025820.GB29746@pek-khao-d1.corp.ad.wrs.com
State Not Applicable
Delegated to: David Miller
Headers show

Commit Message

Kevin Hao July 8, 2014, 2:58 a.m. UTC 
On Mon, Jul 07, 2014 at 09:49:45AM -0400, Tejun Heo wrote:
> Hello,
> 
> On Sun, Jul 06, 2014 at 02:28:40PM +0800, Kevin Hao wrote:
> > +int ata_host_set_queue_depth(struct ata_host *host, unsigned int queue_depth)
> 
> Hmmm... is there a reason we're doing this separately when the same
> information is available from scsi_host_template->can_queue from
> ata_host_register()?

This was my first thought. But given that scsi_host_template are the parameters
passed to the scsi layer, it seems a bit weird to set the ata_host based a
value in that. Anyway if we decide to use can_queue, how about directly use
it in ata_qc_new(), just like the following codes?


Thanks,
Kevin
diff mbox

Patch

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 8f3043165048..4792fea79acf 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4728,14 +4728,17 @@  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;
+	WARN_ON_ONCE(max_queue > ATA_MAX_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)