On 16 June 2014 12:23, Stefan Hajnoczi <[email protected]> wrote:
> From: Chunyan Liu <[email protected]>
>
> Reviewed-by: Eric Blake <[email protected]>
> Reviewed-by: Stefan Hajnoczi <[email protected]>
> Signed-off-by: Dong Xu Wang <[email protected]>
> Signed-off-by: Chunyan Liu <[email protected]>
> Signed-off-by: Stefan Hajnoczi <[email protected]>
> ---
> block/cow.c | 54 ++++++++++++++++++++++++++----------------------------
> 1 file changed, 26 insertions(+), 28 deletions(-)
>
> diff --git a/block/cow.c b/block/cow.c
> index 7e61024..af85753 100644
> --- a/block/cow.c
> +++ b/block/cow.c
> @@ -324,31 +324,24 @@ static void cow_close(BlockDriverState *bs)
> {
> }
>
> -static int cow_create(const char *filename, QEMUOptionParameter *options,
> - Error **errp)
> +static int cow_create(const char *filename, QemuOpts *opts, Error **errp)
> {
> struct cow_header_v2 cow_header;
> struct stat st;
> int64_t image_sectors = 0;
> - const char *image_filename = NULL;
> + char *image_filename = NULL;
> Error *local_err = NULL;
> int ret;
> BlockDriverState *cow_bs;
>
> /* Read out options */
> - while (options && options->name) {
> - if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
> - image_sectors = options->value.n / 512;
> - } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
> - image_filename = options->value.s;
> - }
> - options++;
> - }
> + image_sectors = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0) / 512;
> + image_filename = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
>
> - ret = bdrv_create_file(filename, options, NULL, &local_err);
> + ret = bdrv_create_file(filename, NULL, opts, &local_err);
> if (ret < 0) {
> error_propagate(errp, local_err);
> - return ret;
> + goto exit;
> }
>
> cow_bs = NULL;
This change means we now have a 'goto exit' before cow_bs
is initialized, and the exit: code path uses cow_bs:
>
> exit:
> + g_free(image_filename);
> bdrv_unref(cow_bs);
> return ret;
> }
clang 3.4 correctly warns:
/home/petmay01/linaro/qemu-from-laptop/qemu/block/cow.c:342:9:
warning: variable 'cow_bs' is used uninitialized whenever 'if'
condition is true [-Wsometimes-uninitialized]
if (ret < 0) {
^~~~~~~
/home/petmay01/linaro/qemu-from-laptop/qemu/block/cow.c:386:16: note:
uninitialized use occurs here
bdrv_unref(cow_bs);
^~~~~~
/home/petmay01/linaro/qemu-from-laptop/qemu/block/cow.c:342:5: note:
remove the 'if' if its condition is always false
if (ret < 0) {
^~~~~~~~~~~~~~
/home/petmay01/linaro/qemu-from-laptop/qemu/block/cow.c:335:29: note:
initialize the variable 'cow_bs' to silence this warning
BlockDriverState *cow_bs;
^
= NULL
1 warning generated.
Patch to follow.
thanks
-- PMM
