tree 4d4b665926d919231ec28e48475c8733125b077f
parent 11ef3e43726e9e33957badd1fe12b325a8a29919
author Nathan Chancellor <nathan@kernel.org> 1617911098 -0700
committer Commit Bot <commit-bot@chromium.org> 1618804438 +0000

FROMLIST: block: Disable -Walign-mismatch for blk-mq.c

LLVM 13 adds a new warning, -Walign-mismatch, which has an instance in
blk_mq_complete_send_ipi():

block/blk-mq.c:630:39: warning: passing 8-byte aligned argument to
32-byte aligned parameter 2 of 'smp_call_function_single_async' may
result in an unaligned pointer access [-Walign-mismatch]
                smp_call_function_single_async(cpu, &rq->csd);
                                                    ^
1 warning generated.

This is expected after commit 4ccafe032005 ("block: unalign
call_single_data in struct request"), which purposefully unaligned the
structure to save space. Given that there is no real alignment
requirement and there have been no reports of issues since that change,
it should be safe to disable the warning for this one translation unit.

Link: https://github.com/ClangBuiltLinux/linux/issues/1328
Link: https://lore.kernel.org/r/20210310182307.zzcbi5w5jrmveld4@archlinux-ax161/
Link: https://lore.kernel.org/r/20210330230249.709221-1-jiancai@google.com/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
(am from https://lore.kernel.org/patchwork/patch/1410076/)
(also found at https://lore.kernel.org/r/20210408194458.501617-1-nathan@kernel.org)

BUG=chromium:1193732
TEST=CQ

Signed-off-by: Jian Cai <jiancai@google.com>
Signed-off-by: Manoj Gupta <manojgupta@chromium.org>
Change-Id: I9d5a244e14e6c374d88811d4e8414b91f415bfce
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2831759
Reviewed-by: Sean Paul <seanpaul@chromium.org>