path: root/drivers/sbus
diff options
authorTejun Heo <tj@kernel.org>2009-05-08 11:54:16 +0900
committerJens Axboe <jens.axboe@oracle.com>2009-05-11 09:52:18 +0200
commit9934c8c04561413609d2bc38c6b9f268cba774a4 (patch)
tree30dd8f7be54f9b2e03094de9cd03b6a9ee2909cd /drivers/sbus
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 'drivers/sbus')
1 files changed, 3 insertions, 9 deletions
diff --git a/drivers/sbus/char/jsflash.c b/drivers/sbus/char/jsflash.c
index f572a4a1d14..6d465168468 100644
--- a/drivers/sbus/char/jsflash.c
+++ b/drivers/sbus/char/jsflash.c
@@ -186,10 +186,7 @@ static void jsfd_do_request(struct request_queue *q)
struct request *req;
- req = elv_next_request(q);
- if (req)
- blkdev_dequeue_request(req);
+ req = blk_fetch_request(q);
while (req) {
struct jsfd_part *jdp = req->rq_disk->private_data;
unsigned long offset = blk_rq_pos(req) << 9;
@@ -212,11 +209,8 @@ static void jsfd_do_request(struct request_queue *q)
jsfd_read(req->buffer, jdp->dbase + offset, len);
err = 0;
- if (!__blk_end_request_cur(req, err)) {
- req = elv_next_request(q);
- if (req)
- blkdev_dequeue_request(req);
- }
+ if (!__blk_end_request_cur(req, err))
+ req = blk_fetch_request(q);