Jens Axboe wrote:
On Thu, Jul 20 2006, Jeff Garzik wrote:
James Bottomley wrote:
On Thu, 2006-07-20 at 17:27 -0400, Jeff Garzik wrote:
Since _no individual SCSI driver_ uses the block layer
tagging, it is likely that some instability and core kernel
development
will occur, in order to make that work.
That's not quite true: 53c700 and tmscsim both use it ... I could with
the usage were wider, but at least 53c700 has pretty regular and
constant usage ... enough I think to validate the block tag code (it's
been using it for the last three years).
Not for the case being discussed in this thread, adapter-wide tags.
That just means the map is shared, otherwise there should be little if
any difference.
AFAICS, no file in include/scsi/* or drivers/scsi/* ever calls
blk_queue_init_tags() with a non-NULL third arg.
grpe again, it's in scsi_tcq.h.
What tree are you looking at?
There is only one user in the entire tree, and NULL is hardcoded as the
third arg. This is 2.6.18-rc2:
[jgarzik@pretzel linux-2.6]$ grep -r blk_queue_init_tags *
block/ll_rw_blk.c: * blk_queue_init_tags - initialize the queue tag info
block/ll_rw_blk.c:int blk_queue_init_tags(request_queue_t *q, int depth,
block/ll_rw_blk.c:EXPORT_SYMBOL(blk_queue_init_tags);
Documentation/block/biodoc.txt: blk_queue_init_tags(request_queue_t *q, int depth)
include/linux/blkdev.h:extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
include/scsi/scsi_tcq.h: blk_queue_init_tags(sdev->request_queue, depth, NULL);
Regards,
Jeff
-
: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
