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scsi: always assign block layer tags if enabled

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Allow a driver to ask for block layer tags by setting .use_blk_tags in the
host template, in which case it will always see a valid value in
request->tag, similar to the behavior when using blk-mq.  This means even
SCSI "untagged" commands will now have a tag, which is especially useful
when using a host-wide tag map.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
This commit is contained in:
Christoph Hellwig
2014-11-03 14:09:02 +01:00
parent e2eddf4d53
commit 2ecb204d07
33 changed files with 86 additions and 168 deletions
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5
include/scsi/scsi_host.h
View File

@@ -421,6 +421,11 @@ struct scsi_host_template {
*/
unsigned char present;
/*
* Let the block layer assigns tags to all commands.
*/
unsigned use_blk_tags:1;
/*
* This specifies the mode that a LLD supports.
*/

34
include/scsi/scsi_tcq.h
View File

@@ -45,40 +45,6 @@ static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
break;
}
}
/**
* scsi_activate_tcq - turn on tag command queueing
* @SDpnt: device to turn on TCQ for
* @depth: queue depth
*
* Notes:
* Eventually, I hope depth would be the maximum depth
* the device could cope with and the real queue depth
* would be adjustable from 0 to depth.
**/
static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
{
if (!sdev->tagged_supported)
return;
if (shost_use_blk_mq(sdev->host))
queue_flag_set_unlocked(QUEUE_FLAG_QUEUED, sdev->request_queue);
else if (!blk_queue_tagged(sdev->request_queue))
blk_queue_init_tags(sdev->request_queue, depth,
sdev->host->bqt);
scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
}
/**
* scsi_deactivate_tcq - turn off tag command queueing
* @SDpnt: device to turn off TCQ for
**/
static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
{
if (blk_queue_tagged(sdev->request_queue))
blk_queue_free_tags(sdev->request_queue);
scsi_adjust_queue_depth(sdev, 0, depth);
}
static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
int unique_tag)