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Re: [PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
From: |
Kevin Wolf |
Subject: |
Re: [PATCH [repost]] block/blkio: Don't assume size_t is 64 bit |
Date: |
Tue, 30 Jan 2024 09:51:59 +0100 |
Am 29.01.2024 um 19:53 hat Richard W.M. Jones geschrieben:
> With GCC 14 the code failed to compile on i686 (and was wrong for any
> version of GCC):
>
> ../block/blkio.c: In function ‘blkio_file_open’:
> ../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’ from
> incompatible pointer type [-Wincompatible-pointer-types]
> 857 | &s->mem_region_alignment);
> | ^~~~~~~~~~~~~~~~~~~~~~~~
> | |
> | size_t * {aka unsigned int *}
> In file included from ../block/blkio.c:12:
> /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
> unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
> 49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
> *value);
> |
> ~~~~~~~~~~^~~~~
>
> Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Why not simply make BDRVBlkioState.mem_region_alignment a uint64_t
instead of keeping it size_t and doing an additional conversion with
a check that requires an #if (probably to avoid a warning on 64 bit
hosts because the condition is never true)?
Kevin
> block/blkio.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/block/blkio.c b/block/blkio.c
> index 0a0a6c0f5fd..52d78935147 100644
> --- a/block/blkio.c
> +++ b/block/blkio.c
> @@ -794,6 +794,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> *options, int flags,
> const char *blkio_driver = bs->drv->protocol_name;
> BDRVBlkioState *s = bs->opaque;
> int ret;
> + uint64_t val;
>
> ret = blkio_create(blkio_driver, &s->blkio);
> if (ret < 0) {
> @@ -854,7 +855,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> *options, int flags,
>
> ret = blkio_get_uint64(s->blkio,
> "mem-region-alignment",
> - &s->mem_region_alignment);
> + &val);
> if (ret < 0) {
> error_setg_errno(errp, -ret,
> "failed to get mem-region-alignment: %s",
> @@ -862,6 +863,15 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> *options, int flags,
> blkio_destroy(&s->blkio);
> return ret;
> }
> +#if HOST_LONG_BITS == 32
> + if (val > SIZE_MAX) {
> + error_setg_errno(errp, ERANGE,
> + "mem-region-alignment too large for size_t");
> + blkio_destroy(&s->blkio);
> + return -ERANGE;
> + }
> +#endif
> + s->mem_region_alignment = (size_t)val;
>
> ret = blkio_get_bool(s->blkio,
> "may-pin-mem-regions",
> --
> 2.43.0
>