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From: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Date: Tue, 7 May 2024 06:17:28 +0900
Message-ID: <CAKFNMokwnkku4tHcaAJPmFaBONZqoTMOLtKh_A7kcjzoxj3QZw@mail.gmail.com>
Subject: Re: [PATCH -mm 1/2] nilfs2: use integer type instead of enum req_op
 for event tracing header
To: Bart Van Assche <bvanassche@acm.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-nilfs@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Jens Axboe <axboe@kernel.dk>
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On Tue, May 7, 2024 at 2:26=E2=80=AFAM Bart Van Assche wrote:
>
> On 5/5/24 12:04 PM, Ryusuke Konishi wrote:
> > I also tried typecasting on the declaration header side of event
> > tracing, but so far, the sparse warnings don't go away except for the
> > patch I first proposed.
>
> How about this patch?
>
> diff --git a/include/trace/events/nilfs2.h b/include/trace/events/nilfs2.=
h
> index 8efc6236f57c..b1a364a33a62 100644
> --- a/include/trace/events/nilfs2.h
> +++ b/include/trace/events/nilfs2.h
> @@ -200,7 +200,11 @@ TRACE_EVENT(nilfs2_mdt_submit_block,
>                     __field(struct inode *, inode)
>                     __field(unsigned long, ino)
>                     __field(unsigned long, blkoff)
> -                   __field(enum req_op, mode)
> +                   /*
> +                    * Use field_struct to avoid is_signed_type() on the =
bitwise
> +                    * type enum req_op.
> +                    */
> +                   __field_struct(enum req_op, mode)
>             ),
>
>             TP_fast_assign(
>
> Thanks,
>
> Bart.

Great!  This patch removed the sparse warnings.

It passed multiple build methods and did not break either tracing or
nilfs2 functionality in operational testing.

I never thought of using __field_struct for enum type, but looking at
the definition it looks like it can be used to just avoid
is_signed_type() without any side effects.   So, this patch looks
better than mine.

If you don't mind, could you complete this change as a patch by adding
a commit message and related tags?

Thanks,
Ryusuke Konishi