| Message ID | Zz0TEX3GycUEmISN@kspp (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [next] ext4: avoid dozens of -Wflex-array-member-not-at-end warnings | expand |
On Tue, Nov 19, 2024 at 04:37:05PM -0600, Gustavo A. R. Silva wrote: > -Wflex-array-member-not-at-end was introduced in GCC-14, and we > are getting ready to enable it, globally. > > Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of > a flexible structure (`struct shash_desc`) where the size of the > flexible-array member (`__ctx`) is known at compile-time, and > refactor the rest of the code, accordingly. > > So, with these changes, fix 38 of the following warnings: > > fs/ext4/ext4.h:2471:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks, for this patch! It appears that this patch has since been obviated by Eric Bigger's commit f2b4fa19647e (" ext4: switch to using the crc32c library"), which landed during this merge window, so this patch should not be needed. - Ted
> Thanks, for this patch! It appears that this patch has since been > obviated by Eric Bigger's commit f2b4fa19647e (" ext4: switch to using > the crc32c library"), which landed during this merge window, so this > patch should not be needed. Oh, nice! Thanks for letting me know. :) -Gustavo
On Fri, Feb 07, 2025 at 09:39:42AM +1030, Gustavo A. R. Silva wrote: > > > Thanks, for this patch! It appears that this patch has since been > > obviated by Eric Bigger's commit f2b4fa19647e (" ext4: switch to using > > the crc32c library"), which landed during this merge window, so this > > patch should not be needed. > > Oh, nice! Thanks for letting me know. :) Yeah, apologiues for not getting back to you earlier. Between travel and the holidays, I didn't have time to process patches for the merge window which just closed, so I'm not catching up on the backlog. In any case, Eric's commit is in 6.14-rc1, so you should see the flex array warnings from the ext4 checksum inline function. - Ted
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 74f2071189b2..edcbe189ff34 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2460,22 +2460,24 @@ static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize) #define DX_HASH_SIPHASH 6 #define DX_HASH_LAST DX_HASH_SIPHASH +#define EXT4_MAX_CHECKSUM_SIZE 4 + static inline u32 ext4_chksum(struct ext4_sb_info *sbi, u32 crc, const void *address, unsigned int length) { - struct { - struct shash_desc shash; - char ctx[4]; - } desc; + DEFINE_RAW_FLEX(struct shash_desc, desc, __ctx, + DIV_ROUND_UP(EXT4_MAX_CHECKSUM_SIZE, + sizeof(*((struct shash_desc *)0)->__ctx))); - BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver)!=sizeof(desc.ctx)); + BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver) != + EXT4_MAX_CHECKSUM_SIZE); - desc.shash.tfm = sbi->s_chksum_driver; - *(u32 *)desc.ctx = crc; + desc->tfm = sbi->s_chksum_driver; + *(u32 *)desc->__ctx = crc; - BUG_ON(crypto_shash_update(&desc.shash, address, length)); + BUG_ON(crypto_shash_update(desc, address, length)); - return *(u32 *)desc.ctx; + return *(u32 *)desc->__ctx; } #ifdef __KERNEL__
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are getting ready to enable it, globally. Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of a flexible structure (`struct shash_desc`) where the size of the flexible-array member (`__ctx`) is known at compile-time, and refactor the rest of the code, accordingly. So, with these changes, fix 38 of the following warnings: fs/ext4/ext4.h:2471:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- Worth mentioning is that this issue is pretty much the same as this other one: https://git.kernel.org/linus/2bd9077b6261 Thanks! fs/ext4/ext4.h | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)