| Message ID | 20250409182914.4725-2-stefanha@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | block: discard alignment fixes | expand |
On Wed, Apr 09, 2025 at 02:29:13PM -0400, Stefan Hajnoczi wrote: > Populate the pdiscard_alignment block limit so the block layer is able > align discard requests correctly. > > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> > --- > block/file-posix.c | 56 +++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 55 insertions(+), 1 deletion(-) > > diff --git a/block/file-posix.c b/block/file-posix.c > index 56d1972d15..2a1e1f48c0 100644 > --- a/block/file-posix.c > +++ b/block/file-posix.c > @@ -1276,10 +1276,10 @@ static int get_sysfs_zoned_model(struct stat *st, BlockZoneModel *zoned) > } > #endif /* defined(CONFIG_BLKZONED) */ > > +#ifdef CONFIG_LINUX > /* > * Get a sysfs attribute value as a long integer. > */ > -#ifdef CONFIG_LINUX > static long get_sysfs_long_val(struct stat *st, const char *attribute) Random change to pull the comment inside of the #if, but tangentially related so I don't mind keeping it here. > { > g_autofree char *str = NULL; > @@ -1299,6 +1299,30 @@ static long get_sysfs_long_val(struct stat *st, const char *attribute) > } > return ret; > } > + > +/* > + * Get a sysfs attribute value as a uint32_t. > + */ > +static int get_sysfs_u32_val(struct stat *st, const char *attribute, > + uint32_t *u32) > +{ > + g_autofree char *str = NULL; > + const char *end; > + unsigned int val; > + int ret; > + > + ret = get_sysfs_str_val(st, attribute, &str); > + if (ret < 0) { > + return ret; > + } > + > + /* The file is ended with '\n', pass 'end' to accept that. */ > + ret = qemu_strtoui(str, &end, 10, &val); > + if (ret == 0 && end && *end == '\0') { > + *u32 = val; > + } > + return ret; > +} > #endif May be worth amending this line to "#endif /* CONFIG_LINUX */" now that it is further from the opening #if. Reviewed-by: Eric Blake <eblake@redhat.com>
diff --git a/block/file-posix.c b/block/file-posix.c index 56d1972d15..2a1e1f48c0 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1276,10 +1276,10 @@ static int get_sysfs_zoned_model(struct stat *st, BlockZoneModel *zoned) } #endif /* defined(CONFIG_BLKZONED) */ +#ifdef CONFIG_LINUX /* * Get a sysfs attribute value as a long integer. */ -#ifdef CONFIG_LINUX static long get_sysfs_long_val(struct stat *st, const char *attribute) { g_autofree char *str = NULL; @@ -1299,6 +1299,30 @@ static long get_sysfs_long_val(struct stat *st, const char *attribute) } return ret; } + +/* + * Get a sysfs attribute value as a uint32_t. + */ +static int get_sysfs_u32_val(struct stat *st, const char *attribute, + uint32_t *u32) +{ + g_autofree char *str = NULL; + const char *end; + unsigned int val; + int ret; + + ret = get_sysfs_str_val(st, attribute, &str); + if (ret < 0) { + return ret; + } + + /* The file is ended with '\n', pass 'end' to accept that. */ + ret = qemu_strtoui(str, &end, 10, &val); + if (ret == 0 && end && *end == '\0') { + *u32 = val; + } + return ret; +} #endif static int hdev_get_max_segments(int fd, struct stat *st) @@ -1318,6 +1342,23 @@ static int hdev_get_max_segments(int fd, struct stat *st) #endif } +/* + * Fills in *dalign with the discard alignment and returns 0 on success, + * -errno otherwise. + */ +static int hdev_get_pdiscard_alignment(struct stat *st, uint32_t *dalign) +{ +#ifdef CONFIG_LINUX + /* + * Note that Linux "discard_granularity" is QEMU "discard_alignment". Linux + * "discard_alignment" is something else. + */ + return get_sysfs_u32_val(st, "discard_granularity", dalign); +#else + return -ENOTSUP; +#endif +} + #if defined(CONFIG_BLKZONED) /* * If the reset_all flag is true, then the wps of zone whose state is @@ -1527,6 +1568,19 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp) } } + if (S_ISBLK(st.st_mode)) { + uint32_t dalign = 0; + int ret; + + ret = hdev_get_pdiscard_alignment(&st, &dalign); + if (ret == 0) { + /* Must be a multiple of request_alignment */ + assert(dalign % bs->bl.request_alignment == 0); + + bs->bl.pdiscard_alignment = dalign; + } + } + raw_refresh_zoned_limits(bs, &st, errp); }
Populate the pdiscard_alignment block limit so the block layer is able align discard requests correctly. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- block/file-posix.c | 56 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 55 insertions(+), 1 deletion(-)