shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-05 10:31:46 +09:00
Code Issues Packages Projects Releases Wiki Activity

block: define bvec_iter as __packed __aligned(4)

Browse Source 
[ Upstream commit 7838b4656110d950afdd92a081cc0f33e23e0ea8 ]

In commit 19416123ab ("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: 19416123ab ("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>
This commit is contained in:
Ming Lei
2024-02-25 11:01:41 +08:00
committed by Greg Kroah-Hartman
parent c6ff5fb6b1
commit 0e351d1aa2
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/bvec.h
View File

@@ -59,7 +59,7 @@ struct bvec_iter {
unsigned int bi_bvec_done; /* number of bytes completed in unsigned int bi_bvec_done; /* number of bytes completed in
current bvec */ current bvec */
} __packed; } __packed __aligned(4);
struct bvec_iter_all { struct bvec_iter_all {
struct bio_vec bv; struct bio_vec bv;