On 11/5/19 5:50 AM, Bean Huo (beanhuo) wrote:
- wait_event(hba->tm_tag_wq, ufshcd_get_tm_free_slot(hba,
&free_slot));
+ req = blk_get_request(q, REQ_OP_DRV_OUT, BLK_MQ_REQ_RESERVED);
+ req->end_io_data = &wait;
+ free_slot = req->tag;
+ WARN_ON_ONCE(free_slot < 0 || free_slot >= hba->nutmrs);
ufshcd_hold(hba, false);
Understand now , you delete ufshcd_get_tm_free_slot(). Run a big circle to get a free_slot from reserved tags by calling blk_get_request().
But UFS data transfer queue depth is 32, not 32 + hba->nutmrs. How to make sure we see the tag is consistent across block/scsi/ufs?
Hi Bean,
Please have a look at the blk_mq_get_tag() function in the block layer.
The implementation of that function makes it clear that the tags with
numbers [0 .. nr_reserved) are considered reserved tags and also that
the tags with numbers [nr_reserved .. queue_depth) are considered
regular tags. In other words, adding hba->nutmrs to can_queue does not
increase the queue depth because the same number of tags are considered
reserved tags.
Bart.
