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authorMing Lei <ming.lei@redhat.com>2024-02-25 11:01:41 +0800
committerLinus Torvalds <torvalds@linux-foundation.org>2024-03-02 09:15:01 -0800
commit7838b4656110d950afdd92a081cc0f33e23e0ea8 (patch)
treee95689b199bb60bf8dbf6aac556b5f30bd11aeb3
parent7fd664466a8f8e50099ce0a7bb40515782cb3569 (diff)
block: define bvec_iter as __packed __aligned(4)
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>
-rw-r--r--include/linux/bvec.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 555aae5448ae..bd1e361b351c 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;