From: Jens Axboe <axboe@suse.de>
To: Bharata B Rao <bharata@in.ibm.com>
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: Thu, 15 May 2003 09:29:37 +0200 [thread overview]
Message-ID: <20030515072937.GT15261@suse.de> (raw)
In-Reply-To: <20030515093731.N31823@in.ibm.com>
On Thu, May 15 2003, Bharata B Rao wrote:
> On Wed, May 14, 2003 at 10:32:24AM +0200, Jens Axboe wrote:
> >
> > That really has to be locked down as well. For your purpose, I think the
> > use of elv_queue_empty() is much better even though it really is an
> > internal function. The problem mainly comes from AS, that can have non
> > empty queue but still return NULL in elv_next_request().
> >
> > But yes, it needs to be locked. If you have pinned the other CPUs, then
> > I suppose it should work. But it's still a violation of the locking
> > rules, and one would get in trouble dropping the queue lock from the io
> > scheduler elevator_queue_empty_fn. No one does that currently, but... So
> > please take the lock.
> >
>
> Ok, Now we try to acquire the lock and refuse to dump if we don't get
> the lock.
>
> --- 2569+mjb1/drivers/dump/dump_blockdev.c.orig Wed May 14 13:23:36 2003
> +++ 2569+mjb1/drivers/dump/dump_blockdev.c Thu May 15 09:26:12 2003
> @@ -258,10 +258,19 @@
> 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);
> + int ret;
> +
> + /* If we can't get request queue lock, refuse to take the dump */
> + if (!spin_trylock(q->queue_lock))
> + return -EBUSY;
> +
> + ret = elv_queue_empty(q);
> + spin_unlock(q->queue_lock);
>
> /* 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 (!ret) {
> /* i/o in flight - safer to quit */
> return -EBUSY;
> }
Are interrupts already disabled at this point? If yes, then it looks
fine.
--
Jens Axboe
next prev parent reply other threads:[~2003-05-15 7:20 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
2003-05-14 8:32 ` Jens Axboe
2003-05-15 4:07 ` Bharata B Rao
2003-05-15 7:29 ` Jens Axboe [this message]
2003-05-15 9:16 ` Bharata B Rao
2003-05-15 12:52 ` Martin J. Bligh
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