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scsi: use host wide tags by default

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This patch changes the !blk-mq path to the same defaults as the blk-mq
I/O path by always enabling block tagging, and always using host wide
tags.  We've had blk-mq available for a few releases so bugs with
this mode should have been ironed out, and this ensures we get better
coverage of over tagging setup over different configs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
This commit is contained in:
Christoph Hellwig
2015-10-08 09:28:04 +01:00
committed by James Bottomley
parent 720ba808e9
commit 64d513ac31
36 changed files with 39 additions and 211 deletions
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5
include/scsi/scsi_host.h
View File

@@ -405,11 +405,6 @@ struct scsi_host_template {
/* If use block layer to manage tags, this is tag allocation policy */
int tag_alloc_policy;
/*
* Let the block layer assigns tags to all commands.
*/
unsigned use_blk_tags:1;
/*
* Track QUEUE_FULL events and reduce queue depth on demand.
*/

95
include/scsi/scsi_tcq.h
View File

@@ -10,91 +10,36 @@
#ifdef CONFIG_BLOCK
static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
int unique_tag)
{
u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
struct request *req = NULL;
if (hwq < shost->tag_set.nr_hw_queues)
req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
blk_mq_unique_tag_to_tag(unique_tag));
return req ? (struct scsi_cmnd *)req->special : NULL;
}
/**
* scsi_find_tag - find a tagged command by device
* @SDpnt: pointer to the ScSI device
* @tag: tag generated by blk_mq_unique_tag()
*
* Notes:
* Only works with tags allocated by the generic blk layer.
**/
static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
{
struct request *req;
if (tag != SCSI_NO_TAG) {
if (shost_use_blk_mq(sdev->host))
return scsi_mq_find_tag(sdev->host, tag);
req = blk_queue_find_tag(sdev->request_queue, tag);
return req ? (struct scsi_cmnd *)req->special : NULL;
}
/* single command, look in space */
return sdev->current_cmnd;
}
/**
* scsi_init_shared_tag_map - create a shared tag map
* @shost: the host to share the tag map among all devices
* @depth: the total depth of the map
*/
static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
{
/*
* We always have a shared tag map around when using blk-mq.
*/
if (shost_use_blk_mq(shost))
return 0;
/*
* If the shared tag map isn't already initialized, do it now.
* This saves callers from having to check ->bqt when setting up
* devices on the shared host (for libata)
*/
if (!shost->bqt) {
shost->bqt = blk_init_tags(depth,
shost->hostt->tag_alloc_policy);
if (!shost->bqt)
return -ENOMEM;
}
return 0;
}
/**
* scsi_host_find_tag - find the tagged command by host
* @shost: pointer to scsi_host
* @tag: tag generated by blk_mq_unique_tag()
* @tag: tag
*
* Notes:
* Only works with tags allocated by the generic blk layer.
* Note: for devices using multiple hardware queues tag must have been
* generated by blk_mq_unique_tag().
**/
static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
int tag)
int tag)
{
struct request *req;
struct request *req = NULL;
if (tag != SCSI_NO_TAG) {
if (shost_use_blk_mq(shost))
return scsi_mq_find_tag(shost, tag);
if (tag == SCSI_NO_TAG)
return NULL;
if (shost_use_blk_mq(shost)) {
u16 hwq = blk_mq_unique_tag_to_hwq(tag);
if (hwq < shost->tag_set.nr_hw_queues) {
req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
blk_mq_unique_tag_to_tag(tag));
}
} else {
req = blk_map_queue_find_tag(shost->bqt, tag);
return req ? (struct scsi_cmnd *)req->special : NULL;
}
return NULL;
if (!req)
return NULL;
return req->special;
}
#endif /* CONFIG_BLOCK */