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Re: [Qemu-devel] [PATCH v3 2/5] raw-posix: Factor block size detection o
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/5] raw-posix: Factor block size detection out of raw_probe_alignment() |
Date: |
Mon, 15 Dec 2014 14:07:00 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
Ekaterina Tumanova <address@hidden> writes:
> Put it in new probe_logical_blocksize().
>
> Signed-off-by: Ekaterina Tumanova <address@hidden>
> ---
> block/raw-posix.c | 44 +++++++++++++++++++++++++++-----------------
> 1 file changed, 27 insertions(+), 17 deletions(-)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index b1af77e..633d5bc 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -217,11 +217,35 @@ static int raw_normalize_devicepath(const char
> **filename)
> }
> #endif
>
> +/*
> + * Set logical block size via ioctl. On success return 0. Otherwise -errno.
Set? I suspect you mean get.
> + */
> +static int probe_logical_blocksize(int fd, unsigned int *sector_size)
> +{
> + /* Try a few ioctls to get the right size */
> +#ifdef BLKSSZGET
> + if (ioctl(fd, BLKSSZGET, sector_size) < 0) {
> + return -errno;
> + }
> +#endif
> +#ifdef DKIOCGETBLOCKSIZE
> + if (ioctl(fd, DKIOCGETBLOCKSIZE, sector_size) < 0) {
> + return -errno;
> + }
> +#endif
> +#ifdef DIOCGSECTORSIZE
> + if (ioctl(fd, DIOCGSECTORSIZE, sector_size) < 0) {
> + return -errno;
> + }
> +#endif
> +
> + return 0;
> +}
> +
> static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
> {
> BDRVRawState *s = bs->opaque;
> char *buf;
> - unsigned int sector_size;
>
> /* For /dev/sg devices the alignment is not really used.
> With buffered I/O, we don't have any restrictions. */
> @@ -231,25 +255,11 @@ static void raw_probe_alignment(BlockDriverState *bs,
> int fd, Error **errp)
> return;
> }
>
> - /* Try a few ioctls to get the right size */
> bs->request_alignment = 0;
> s->buf_align = 0;
> + /* Let's try to use the logical blocksize for the alignment. */
> + probe_logical_blocksize(fd, &bs->request_alignment);
I figure this works, but perhaps the following would be clearer:
if (probe_logical_blocksize(fd, &bs->request_alignment) < 0) {
bs->request_alignment = 0;
}
Your call.
>
> -#ifdef BLKSSZGET
> - if (ioctl(fd, BLKSSZGET, §or_size) >= 0) {
> - bs->request_alignment = sector_size;
> - }
> -#endif
> -#ifdef DKIOCGETBLOCKSIZE
> - if (ioctl(fd, DKIOCGETBLOCKSIZE, §or_size) >= 0) {
> - bs->request_alignment = sector_size;
> - }
> -#endif
> -#ifdef DIOCGSECTORSIZE
> - if (ioctl(fd, DIOCGSECTORSIZE, §or_size) >= 0) {
> - bs->request_alignment = sector_size;
> - }
> -#endif
> #ifdef CONFIG_XFS
> if (s->is_xfs) {
> struct dioattr da;