6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ming Lei ming.lei@redhat.com
[ Upstream commit 7838b4656110d950afdd92a081cc0f33e23e0ea8 ]
In commit 19416123ab3e ("block: define 'struct bvec_iter' as packed"), what we need is to save the 4byte padding, and avoid `bio` to spread on one extra cache line.
It is enough to define it as '__packed __aligned(4)', as '__packed' alone means byte aligned, and can cause compiler to generate horrible code on architectures that don't support unaligned access in case that bvec_iter is embedded in other structures.
Cc: Mikulas Patocka mpatocka@redhat.com Suggested-by: Linus Torvalds torvalds@linux-foundation.org Fixes: 19416123ab3e ("block: define 'struct bvec_iter' as packed") Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/bvec.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 555aae5448ae4..bd1e361b351c5 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -83,7 +83,7 @@ struct bvec_iter {
unsigned int bi_bvec_done; /* number of bytes completed in current bvec */ -} __packed; +} __packed __aligned(4);
struct bvec_iter_all { struct bio_vec bv;