From: Mike Christie <michaelc@cs.wisc.edu>
To: Andrew Morton <akpm@osdl.org>
Cc: Miquel van Smoorenburg <miquels@cistron.nl>,
linux-lvm@sistina.com, linux-kernel@vger.kernel.org,
Nick Piggin <piggin@cyberone.com.au>, Jens Axboe <axboe@suse.de>
Subject: Re: System hangs after echo value > /sys/block/dm-0/queue/nr_requests
Date: Tue, 30 Dec 2003 16:44:17 -0800 [thread overview]
Message-ID: <3FF21BE1.9070603@cs.wisc.edu> (raw)
In-Reply-To: <20031230034239.27950054.akpm@osdl.org>
[-- Attachment #1: Type: text/plain, Size: 451 bytes --]
Andrew Morton wrote:
> Where queue_requests_store() does wake_up(&rl->wait[READ]);
>
> It looks like nobody has called blk_init_queue() for this queue and the
> waitqueue head is uninitialised.
>
DM, MD, rd and loop use blk_alloc_queue and blk_queue_make_request to
initialize their queue, because they only use the make_request_fn. The
attached patch prevents the queue from being registered if only
blk_alloc_queue was called.
Mike Christie
[-- Attachment #2: queue_attr.patch --]
[-- Type: text/plain, Size: 573 bytes --]
--- linux-2.6.0-orig/drivers/block/ll_rw_blk.c 2003-12-28 23:09:16.000000000 -0800
+++ linux-2.6.0/drivers/block/ll_rw_blk.c 2003-12-30 16:11:00.690504036 -0800
@@ -2902,7 +2902,7 @@ int blk_register_queue(struct gendisk *d
request_queue_t *q = disk->queue;
- if (!q)
+ if (!q || !q->request_fn)
return -ENXIO;
q->kobj.parent = kobject_get(&disk->kobj);
@@ -2929,7 +2929,7 @@ void blk_unregister_queue(struct gendisk
{
request_queue_t *q = disk->queue;
- if (q) {
+ if (q && q->request_fn) {
elv_unregister_queue(q);
kobject_unregister(&q->kobj);
next prev parent reply other threads:[~2003-12-31 0:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-29 13:00 System hangs after echo value > /sys/block/dm-0/queue/nr_requests Miquel van Smoorenburg
2003-12-30 11:42 ` Andrew Morton
2003-12-31 0:44 ` Mike Christie [this message]
2003-12-31 10:32 ` Jens Axboe
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