From: Bharata B Rao <bharata@in.ibm.com>
To: Jens Axboe <axboe@suse.de>
Cc: "Martin J. Bligh" <mbligh@aracnet.com>,
Adrian Bunk <bunk@fs.tum.de>,
linux-kernel <linux-kernel@vger.kernel.org>,
Suparna Bhattacharya <suparna@in.ibm.com>
Subject: Re: 2.5.69-mjb1: undefined reference to `blk_queue_empty'
Date: Wed, 14 May 2003 13:38:43 +0530 [thread overview]
Message-ID: <20030514133843.H31823@in.ibm.com> (raw)
In-Reply-To: <20030513181155.GL17033@suse.de>; from axboe@suse.de on Tue, May 13, 2003 at 08:11:55PM +0200
On Tue, May 13, 2003 at 08:11:55PM +0200, Jens Axboe wrote:
> > >
> > > /* For now we assume we have the device to ourselves */
> > > /* Just a quick sanity check */
> > > - if (!blk_queue_empty(bdev_get_queue(dump_bdev->bdev))) {
> > > + if (elv_next_request(bdev_get_queue(dump_bdev->bdev))) {
> > > /* i/o in flight - safer to quit */
> > > return -EBUSY;
> > > }
>
> this looks horribly racy (of the io scheduler internals corrupting
> kind), I don't see you holding the queue lock here. some io schedulers
> do non-significant amount of work inside they next_request functions,
> moving from back-end lists to dispatch queue.
>
Jens,
All we want to do here is to check if there are requests in the
queue. Hence thinking of using elv_queue_empty(). Do you think
we still need to acquire queue lock for this ? This code will be
run when we have stopped everything else in other cpus by putting
them into spin.
--- 2569+mjb1/drivers/dump/dump_blockdev.c.orig Wed May 14 13:23:36 2003
+++ 2569+mjb1/drivers/dump/dump_blockdev.c Wed May 14 13:24:58 2003
@@ -258,10 +258,11 @@
dump_block_silence(struct dump_dev *dev)
{
struct dump_blockdev *dump_bdev = DUMP_BDEV(dev);
+ struct request_queue *q = bdev_get_queue(dump_bdev->bdev);
/* For now we assume we have the device to ourselves */
/* Just a quick sanity check */
- if (!blk_queue_empty(bdev_get_queue(dump_bdev->bdev))) {
+ if (!elv_queue_empty(q)) {
/* i/o in flight - safer to quit */
return -EBUSY;
}
Regards,
Bharata.
next prev parent reply other threads:[~2003-05-14 8:07 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-11 3:44 2.5.69-mjb1 Martin J. Bligh
2003-05-11 13:33 ` 2.5.69-mjb1 Zwane Mwaikambo
2003-05-11 13:12 ` 2.5.69-mjb1 Martin J. Bligh
2003-05-12 13:29 ` 2.5.69-mjb1 William Lee Irwin III
2003-05-12 12:40 ` 2.5.69-mjb1 Martin J. Bligh
2003-05-12 15:03 ` 2.5.69-mjb1 William Lee Irwin III
2003-05-12 13:07 ` 2.5.69-mjb1 Martin J. Bligh
2003-05-12 15:34 ` 2.5.69-mjb1 Dave Hansen
2003-05-12 13:43 ` 2.5.69-mjb1 Martin J. Bligh
2003-05-12 15:11 ` 2.5.69-mjb1 Dave Hansen
2003-05-12 15:05 ` 2.5.69-mjb1 Dave Hansen
2003-05-13 1:23 ` [Lse-tech] 2.5.69-mjb1 William Lee Irwin III
2003-05-13 3:41 ` Martin J. Bligh
2003-05-13 6:27 ` William Lee Irwin III
2003-05-13 6:42 ` Andi Kleen
2003-05-12 20:51 ` 2.5.69-mjb1: undefined reference to `blk_queue_empty' Adrian Bunk
2003-05-13 3:51 ` Martin J. Bligh
2003-05-13 7:18 ` Bharata B Rao
2003-05-13 13:58 ` Martin J. Bligh
2003-05-13 18:11 ` Jens Axboe
2003-05-14 8:08 ` Bharata B Rao [this message]
2003-05-14 8:32 ` Jens Axboe
2003-05-15 4:07 ` Bharata B Rao
2003-05-15 7:29 ` Jens Axboe
2003-05-15 9:16 ` Bharata B Rao
2003-05-15 12:52 ` Martin J. Bligh
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