Re: [PATCH] rbd: silence GCC warnings
From: Sage Weil
Date: Tue Jun 18 2013 - 11:10:52 EST
This was already fixed up in teh testing branch; thanks!
On Mon, 17 Jun 2013, Paul Bolle wrote:
> Building rbd.o triggers two GCC warnings:
> drivers/block/rbd.c: In function ?rbd_img_request_fill?:
> drivers/block/rbd.c:1272:22: warning: ?bio_list? may be used uninitialized in this function [-Wmaybe-uninitialized]
> drivers/block/rbd.c:2170:14: note: ?bio_list? was declared here
> drivers/block/rbd.c:2231:10: warning: ?pages? may be used uninitialized in this function [-Wmaybe-uninitialized]
>
> Apparently GCC has trouble determining that "bio_list" is unused if "type"
> is "OBJ_REQUEST_PAGES" and, conversely, that "pages" will be unused if
> "type" is "OBJ_REQUEST_BIO". Add harmless initializations to NULL to
> help GCC.
>
> Signed-off-by: Paul Bolle <pebolle@xxxxxxxxxx>
> ---
> 0) Compile tested only.
>
> 1) These warnings were introduced in v3.10-rc1, apparently through
> commit f1a4739f33 ("rbd: support page array image requests").
>
> 2) Note that
> rbd_assert(type == OBJ_REQUEST_PAGES);
>
> seems redundant. I see no way that this assertion could ever be false.
>
> drivers/block/rbd.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 3063452..b8a58178 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -2185,9 +2185,11 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
> if (type == OBJ_REQUEST_BIO) {
> bio_list = data_desc;
> rbd_assert(img_offset == bio_list->bi_sector << SECTOR_SHIFT);
> + pages = NULL;
> } else {
> rbd_assert(type == OBJ_REQUEST_PAGES);
> pages = data_desc;
> + bio_list = NULL;
> }
>
> while (resid) {
> --
> 1.8.1.4
>
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