lkml.org 
[lkml]   [2019]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] dm dust: Convert an 'else if' into an 'else' in dust_map
On Mon, Apr 29, 2019 at 7:10 PM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> When building with -Wsometimes-uninitialized, Clang warns:
>
> drivers/md/dm-dust.c:216:11: warning: variable 'ret' is used
> uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
> else if (bio_data_dir(bio) == WRITE)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/bio.h:69:2: note: expanded from macro 'bio_data_dir'
> (op_is_write(bio_op(bio)) ? WRITE : READ)
> ^
> drivers/md/dm-dust.c:219:9: note: uninitialized use occurs here
> return ret;
> ^~~
> drivers/md/dm-dust.c:216:7: note: remove the 'if' if its condition is
> always true
> else if (bio_data_dir(bio) == WRITE)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/md/dm-dust.c:209:9: note: initialize the variable 'ret' to
> silence this warning
> int ret;
> ^
> = 0
> 1 warning generated.
>
> It isn't wrong; however, bio_data_dir will only ever return READ and
> WRITE so the second 'else if' can really become an 'else' to silence
> this warning and not change the final meaning of the code.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/462
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> drivers/md/dm-dust.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-dust.c b/drivers/md/dm-dust.c
> index 997830984893..5baeb56679ed 100644
> --- a/drivers/md/dm-dust.c
> +++ b/drivers/md/dm-dust.c
> @@ -213,7 +213,7 @@ static int dust_map(struct dm_target *ti, struct bio *bio)
>
> if (bio_data_dir(bio) == READ)
> ret = dust_map_read(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb);
> - else if (bio_data_dir(bio) == WRITE)
> + else
> ret = dust_map_write(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb);
>
> return ret;
> --
> 2.21.0
>

Thanks for the patch.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
--
Thanks,
~Nick Desaulniers

\
 
 \ /
  Last update: 2019-05-01 00:32    [W:0.048 / U:0.252 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site