Re: [PATCH 2/3] loop: No need to initialize ->queue_lock explicitlybefore calling blk_cleanup_queue()

From: Vivek Goyal
Date: Tue Feb 22 2011 - 09:21:04 EST


On Tue, Feb 22, 2011 at 09:30:32AM +0200, Sergey Senozhatsky wrote:
> On (02/21/11 22:53), Vivek Goyal wrote:
> > o Now we initialize ->queue_lock at queue allocation time so driver does
> > not have to worry about initializing it before calling blk_cleanup_queue().
> >
> > Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> > ---
> > drivers/block/loop.c | 3 ---
> > 1 files changed, 0 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> > index 49e6a54..44e18c0 100644
> > --- a/drivers/block/loop.c
> > +++ b/drivers/block/loop.c
> > @@ -1641,9 +1641,6 @@ out:
> >
> > static void loop_free(struct loop_device *lo)
> > {
> > - if (!lo->lo_queue->queue_lock)
> > - lo->lo_queue->queue_lock = &lo->lo_queue->__queue_lock;
> > -
> > blk_cleanup_queue(lo->lo_queue);
> > put_disk(lo->lo_disk);
> > list_del(&lo->lo_list);
>
> Hi,
>
> (just for note)
> There is an incremental patch fixing this case in Andrew's mm tree:
> https://lkml.org/lkml/2011/2/11/165
>
> (block-fix-queue_lock-null-pointer-derefence-in-blk_throtl_exit-v4.patch
> added to -mm tree).

Hi Sergey,

Thinking more about it, initializing queue lock in blk_alloc_queue() seems
to be even more cleaner to me instead of initializing it to internal lock
during blk_cleanup_queue(). If others like the idea, then we can either
ask Andrew to drop the patch or I can generate one on top of it.

Thanks
Vivek
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