[PATCH] rbd: silence GCC warnings

From: Paul Bolle
Date: Mon Jun 17 2013 - 06:12:52 EST

Building rbd.o triggers two GCC warnings:
drivers/block/rbd.c: In function ârbd_img_request_fillâ:
drivers/block/rbd.c:1272:22: warning: âbio_listâ may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/block/rbd.c:2170:14: note: âbio_listâ was declared here
drivers/block/rbd.c:2231:10: warning: âpagesâ 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) {

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