Re: CDROM ioctl bug (fwd)

From: Peter Osterlund (petero2@telia.com)
Date: Wed Nov 28 2001 - 18:51:46 EST

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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

This archive was generated by hypermail 2b29 : Fri Nov 30 2001 - 21:00:32 EST