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Re: [Qemu-block] [PATCH for-2.9?] block/file-posix.c: Fix unused variabl
From: |
Jeff Cody |
Subject: |
Re: [Qemu-block] [PATCH for-2.9?] block/file-posix.c: Fix unused variable warning on OpenBSD |
Date: |
Wed, 22 Mar 2017 09:58:46 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Mon, Mar 20, 2017 at 06:33:04PM +0000, Peter Maydell wrote:
> On OpenBSD none of the ioctls probe_logical_blocksize() tries
> exist, so the variable sector_size is unused. Refactor the
> code to avoid this (and reduce the duplicated code).
>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> The alternative would be to move the variable so it was
> local to a code block inside each #ifdef, but this seemed
> a bit nicer anyway.
>
> Tentatively tagged 'for-2.9' just because this is the only
> warning in the OpenBSD build, but I don't insist on it.
>
> I've opted to retain the existing behaviour of "try every
> ioctl available and use the last one that works" rather
> than "stop as soon as something worked".
>
> ---
> block/file-posix.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 53febd3..b980d23 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -219,28 +219,28 @@ static int probe_logical_blocksize(int fd, unsigned int
> *sector_size_p)
> {
> unsigned int sector_size;
> bool success = false;
> + int i;
>
> errno = ENOTSUP;
> -
> - /* Try a few ioctls to get the right size */
> + unsigned long ioctl_list[] = {
> #ifdef BLKSSZGET
> - if (ioctl(fd, BLKSSZGET, §or_size) >= 0) {
> - *sector_size_p = sector_size;
> - success = true;
> - }
> + BLKSSZGET,
> #endif
> #ifdef DKIOCGETBLOCKSIZE
> - if (ioctl(fd, DKIOCGETBLOCKSIZE, §or_size) >= 0) {
> - *sector_size_p = sector_size;
> - success = true;
> - }
> + DKIOCGETBLOCKSIZE,
> #endif
> #ifdef DIOCGSECTORSIZE
> - if (ioctl(fd, DIOCGSECTORSIZE, §or_size) >= 0) {
> - *sector_size_p = sector_size;
> - success = true;
> - }
> + DIOCGSECTORSIZE,
> #endif
> + };
> +
> + /* Try a few ioctls to get the right size */
> + for (i = 0; i < ARRAY_SIZE(ioctl_list); i++) {
> + if (ioctl(fd, ioctl_list[i], §or_size) >= 0) {
> + *sector_size_p = sector_size;
> + success = true;
> + }
> + }
>
> return success ? 0 : -errno;
> }
> --
> 2.7.4
>
>
Reviewed-by: Jeff Cody <address@hidden>