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authorTejun Heo <tj@kernel.org>2009-05-07 22:54:16 -0400
committerJens Axboe <jens.axboe@oracle.com>2009-05-11 03:52:18 -0400
commit9934c8c04561413609d2bc38c6b9f268cba774a4 (patch)
tree30dd8f7be54f9b2e03094de9cd03b6a9ee2909cd /block/blk-barrier.c
parent2343046826a8ca426b07601d9593ee046c298b68 (diff)
block: implement and enforce request peek/start/fetch
Till now block layer allowed two separate modes of request execution. A request is always acquired from the request queue via elv_next_request(). After that, drivers are free to either dequeue it or process it without dequeueing. Dequeue allows elv_next_request() to return the next request so that multiple requests can be in flight. Executing requests without dequeueing has its merits mostly in allowing drivers for simpler devices which can't do sg to deal with segments only without considering request boundary. However, the benefit this brings is dubious and declining while the cost of the API ambiguity is increasing. Segment based drivers are usually for very old or limited devices and as converting to dequeueing model isn't difficult, it doesn't justify the API overhead it puts on block layer and its more modern users. Previous patches converted all block low level drivers to dequeueing model. This patch completes the API transition by... * renaming elv_next_request() to blk_peek_request() * renaming blkdev_dequeue_request() to blk_start_request() * adding blk_fetch_request() which is combination of peek and start * disallowing completion of queued (not started) requests * applying new API to all LLDs Renamings are for consistency and to break out of tree code so that it's apparent that out of tree drivers need updating. [ Impact: block request issue API cleanup, no functional change ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Mike Miller <mike.miller@hp.com> Cc: unsik Kim <donari75@gmail.com> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Tim Waugh <tim@cyberelk.net> Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Cc: David S. Miller <davem@davemloft.net> Cc: Laurent Vivier <Laurent@lvivier.info> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: Pierre Ossman <drzeus@drzeus.cx> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Markus Lidel <Markus.Lidel@shadowconnect.com> Cc: Stefan Weinhuber <wein@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-barrier.c')
-rw-r--r--block/blk-barrier.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 8713c2fbc4f6..0ab81a0a7502 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -180,7 +180,7 @@ static inline bool start_ordered(struct request_queue *q, struct request **rqp)
180 } 180 }
181 181
182 /* stash away the original request */ 182 /* stash away the original request */
183 elv_dequeue_request(q, rq); 183 blk_dequeue_request(rq);
184 q->orig_bar_rq = rq; 184 q->orig_bar_rq = rq;
185 rq = NULL; 185 rq = NULL;
186 186
@@ -248,7 +248,7 @@ bool blk_do_ordered(struct request_queue *q, struct request **rqp)
248 * Queue ordering not supported. Terminate 248 * Queue ordering not supported. Terminate
249 * with prejudice. 249 * with prejudice.
250 */ 250 */
251 elv_dequeue_request(q, rq); 251 blk_dequeue_request(rq);
252 __blk_end_request_all(rq, -EOPNOTSUPP); 252 __blk_end_request_all(rq, -EOPNOTSUPP);
253 *rqp = NULL; 253 *rqp = NULL;
254 return false; 254 return false;