From: Guenter Roeck <linux@roeck-us.net>
To: Nathan Chancellor <nathan@kernel.org>, Jian Cai <jiancai@google.com>
Cc: cjdb@google.com, manojgupta@google.com, llozano@google.com,
clang-built-linux@googlegroups.com, Jens Axboe <axboe@kernel.dk>,
Nick Desaulniers <ndesaulniers@google.com>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] blk-mq: fix alignment mismatch.
Date: Tue, 30 Mar 2021 17:26:37 -0700 [thread overview]
Message-ID: <114a5697-9b5c-daf1-f0fc-dc190d4db74d@roeck-us.net> (raw)
In-Reply-To: <20210330232946.m5p7426macyjduzm@archlinux-ax161>
On 3/30/21 4:29 PM, Nathan Chancellor wrote:
> Hi Jian,
>
> On Tue, Mar 30, 2021 at 04:02:49PM -0700, Jian Cai wrote:
>> This fixes the mismatch of alignments between csd and its use as an
>> argument to smp_call_function_single_async, which causes build failure
>> when -Walign-mismatch in Clang is used.
>>
>> Link:
>> http://crrev.com/c/1193732
>>
>> Suggested-by: Guenter Roeck <linux@roeck-us.net>
>> Signed-off-by: Jian Cai <jiancai@google.com>
>
> Thanks for the patch. This is effectively a revert of commit
> 4ccafe032005 ("block: unalign call_single_data in struct request"),
> which I had brought up in this thread:
>
> https://lore.kernel.org/r/20210310182307.zzcbi5w5jrmveld4@archlinux-ax161/
>
> This is obviously a correct fix, I am not just sure what the impact to
> 'struct request' will be.
>
As commit 4ccafe032005 states, it increases the request structure size.
Given the exchange referenced above, I think we'll need to disable
the warning in the block code.
Thanks,
Guenter
> Cheers,
> Nathan
>
>> ---
>> include/linux/blkdev.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
>> index bc6bc8383b43..3b92330d95ad 100644
>> --- a/include/linux/blkdev.h
>> +++ b/include/linux/blkdev.h
>> @@ -231,7 +231,7 @@ struct request {
>> unsigned long deadline;
>>
>> union {
>> - struct __call_single_data csd;
>> + call_single_data_t csd;
>> u64 fifo_time;
>> };
>>
>> --
>> 2.31.0.291.g576ba9dcdaf-goog
>>
next prev parent reply other threads:[~2021-03-31 0:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-30 23:02 [PATCH] blk-mq: fix alignment mismatch Jian Cai
2021-03-30 23:12 ` Guenter Roeck
2021-03-30 23:29 ` Nathan Chancellor
2021-03-31 0:26 ` Guenter Roeck [this message]
2021-03-31 1:31 ` Jian Cai
2021-03-31 21:27 ` Jian Cai
2021-03-31 21:58 ` Nathan Chancellor
2021-03-31 22:06 ` Nick Desaulniers
2021-04-08 17:57 ` Jian Cai
2021-04-08 18:12 ` Nathan Chancellor
2021-04-08 18:42 ` Jian Cai
2021-04-08 19:44 ` [PATCH] block: Disable -Walign-mismatch for blk-mq.c Nathan Chancellor
2021-04-08 19:52 ` Guenter Roeck
2021-03-31 10:38 ` [PATCH] blk-mq: fix alignment mismatch David Laight
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