On Sat, Jan 11 2014 at 12:29pm -0500,
Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote:
> This patch makes dm_bufio_prefetch return 1 on success and 0 on failure.
> A prefetch failure may happen in case of temporary memory shortage.
>
> Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
>
> ---
> drivers/md/dm-bufio.c | 8 ++++++--
> drivers/md/dm-bufio.h | 4 ++--
> 2 files changed, 8 insertions(+), 4 deletions(-)
>
> Index: linux-3.13-rc7/drivers/md/dm-bufio.c
> ===================================================================
> --- linux-3.13-rc7.orig/drivers/md/dm-bufio.c 2014-01-09 16:11:31.000000000 +0100
> +++ linux-3.13-rc7/drivers/md/dm-bufio.c 2014-01-09 16:16:43.000000000 +0100
> @@ -1068,10 +1068,11 @@ void *dm_bufio_new(struct dm_bufio_clien
> }
> EXPORT_SYMBOL_GPL(dm_bufio_new);
>
> -void dm_bufio_prefetch(struct dm_bufio_client *c,
> +int dm_bufio_prefetch(struct dm_bufio_client *c,
> sector_t block, unsigned n_blocks)
> {
> struct blk_plug plug;
> + int success = 1;
>
> LIST_HEAD(write_list);
>
I'd prefer to see a bool used here. Or an actual error code like
-ENOMEM.
> @@ -1104,13 +1105,16 @@ void dm_bufio_prefetch(struct dm_bufio_c
> if (!n_blocks)
> goto flush_plug;
> dm_bufio_lock(c);
> - }
> + } else
> + success = 0;
Why do you continue to do work if a prefetch failed? Why not return
early here?
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