linux-kernel - Re: [PATCH v3 1/6] floppy: don't call alloc_ordered_workqueue inside the alloc

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Date:	Tue, 14 Aug 2012 03:01:21 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	Herton Ronaldo Krzesinski <herton.krzesinski@...onical.com>
Cc:	Jiri Kosina <jkosina@...e.cz>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jens Axboe <axboe@...nel.dk>, Tejun Heo <tj@...nel.org>,
	linux-kernel@...r.kernel.org, Vivek Goyal <vgoyal@...hat.com>
Subject: Re: [PATCH v3 1/6] floppy: don't call alloc_ordered_workqueue
 inside the alloc_disk loop

On Mon, 2012-08-13 at 15:16 -0300, Herton Ronaldo Krzesinski wrote:
> Since commit 070ad7e ("floppy: convert to delayed work and single-thread
> wq"), we end up calling alloc_ordered_workqueue multiple times inside
> the loop, which shouldn't be intended. Besides the leak, other side
> effect in the current code is if blk_init_queue fails, we would end up
> calling unregister_blkdev even if we didn't call yet register_blkdev.
> 
> Just moved the allocation of floppy_wq before the loop, and adjusted the
> code accordingly.
> 
> Cc: stable@...r.kernel.org # 3.5+
> Acked-by: Vivek Goyal <vgoyal@...hat.com>
> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@...onical.com>

Reviewed-by: Ben Hutchings <ben@...adent.org.uk>

> ---
>  drivers/block/floppy.c |   15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
> index a7d6347..c8d9e68 100644
> --- a/drivers/block/floppy.c
> +++ b/drivers/block/floppy.c
> @@ -4138,6 +4138,10 @@ static int __init do_floppy_init(void)
>  
>  	raw_cmd = NULL;
>  
> +	floppy_wq = alloc_ordered_workqueue("floppy", 0);
> +	if (!floppy_wq)
> +		return -ENOMEM;
> +
>  	for (dr = 0; dr < N_DRIVE; dr++) {
>  		disks[dr] = alloc_disk(1);
>  		if (!disks[dr]) {
> @@ -4145,16 +4149,10 @@ static int __init do_floppy_init(void)
>  			goto out_put_disk;
>  		}
>  
> -		floppy_wq = alloc_ordered_workqueue("floppy", 0);
> -		if (!floppy_wq) {
> -			err = -ENOMEM;
> -			goto out_put_disk;
> -		}
> -
>  		disks[dr]->queue = blk_init_queue(do_fd_request, &floppy_lock);
>  		if (!disks[dr]->queue) {
>  			err = -ENOMEM;
> -			goto out_destroy_workq;
> +			goto out_put_disk;
>  		}
>  
>  		blk_queue_max_hw_sectors(disks[dr]->queue, 64);
> @@ -4318,8 +4316,6 @@ out_release_dma:
>  out_unreg_region:
>  	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
>  	platform_driver_unregister(&floppy_driver);
> -out_destroy_workq:
> -	destroy_workqueue(floppy_wq);
>  out_unreg_blkdev:
>  	unregister_blkdev(FLOPPY_MAJOR, "fd");
>  out_put_disk:
> @@ -4335,6 +4331,7 @@ out_put_disk:
>  		}
>  		put_disk(disks[dr]);
>  	}
> +	destroy_workqueue(floppy_wq);
>  	return err;
>  }
>  

-- 
Ben Hutchings
I say we take off; nuke the site from orbit.  It's the only way to be sure.

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