From 7838b4656110d950afdd92a081cc0f33e23e0ea8 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sun, 25 Feb 2024 11:01:41 +0800 Subject: [PATCH] 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 Suggested-by: Linus Torvalds Fixes: 19416123ab3e ("block: define 'struct bvec_iter' as packed") Signed-off-by: Ming Lei Signed-off-by: Linus Torvalds --- 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 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;