From: Peter Osterlund <petero2@telia.com>
To: Ron Lawrence <rlawrence@netraverse.com>
Cc: <linux-kernel@vger.kernel.org>, Jens Axboe <axboe@suse.de>
Subject: Re: CDROM ioctl bug (fwd)
Date: 29 Nov 2001 00:51:46 +0100 [thread overview]
Message-ID: <m2elmi1mjx.fsf@ppro.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.33.0111281009140.1724-100000@monster.jayfay.com>
In-Reply-To: <Pine.LNX.4.33.0111281009140.1724-100000@monster.jayfay.com>
Ron Lawrence <rlawrence@netraverse.com> writes:
> busy. Here are the symptoms of my problem : doing reads from a CDROM
> device intermingled with CDROM_MEDIA_CHANGED ioctls causes long pauses
> during the ioctl. This behavior started in 2.4.10. The ioctl can take a
> very long time to return, especially if reading large chunks.
This patch fixes the problem for my USB CDROM device. Maybe a similar
patch is needed for the IDE case, I haven't looked yet.
In general, who is responsible for unplugging the request queue after
queuing an ioctl command?
--- linux/drivers/scsi/scsi.c.old Thu Nov 29 00:42:16 2001
+++ linux/drivers/scsi/scsi.c Thu Nov 29 00:32:28 2001
@@ -767,14 +767,17 @@
void scsi_wait_req (Scsi_Request * SRpnt, const void *cmnd ,
void *buffer, unsigned bufflen,
int timeout, int retries)
{
+ request_queue_t *q;
DECLARE_COMPLETION(wait);
SRpnt->sr_request.waiting = &wait;
SRpnt->sr_request.rq_status = RQ_SCSI_BUSY;
scsi_do_req (SRpnt, (void *) cmnd,
buffer, bufflen, scsi_wait_done, timeout, retries);
+ q = &SRpnt->sr_device->request_queue;
+ generic_unplug_device(q);
wait_for_completion(&wait);
SRpnt->sr_request.waiting = NULL;
if( SRpnt->sr_command != NULL )
{
--
Peter Österlund petero2@telia.com
Sköndalsvägen 35 http://w1.894.telia.com/~u89404340
S-128 66 Sköndal +46 8 942647
Sweden
next prev parent reply other threads:[~2001-11-28 23:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-11-28 18:44 CDROM ioctl bug (fwd) Ron Lawrence
2001-11-28 23:51 ` Peter Osterlund [this message]
2001-11-29 17:17 ` Ron Lawrence
2001-11-29 17:27 ` Jens Axboe
2001-11-29 18:38 ` Ron Lawrence
2001-11-29 18:48 ` Jens Axboe
2001-11-29 14:21 Douglas Gilbert
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