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Date: Tue, 19 Mar 2024 06:30:41 +1030
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Subject: Re: [PATCH 1/2] btrfs: New helper to clear EXTENT_BUFFER_READING
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To: Tavian Barnes <tavianator@tavianator.com>, linux-btrfs@vger.kernel.org
Cc: Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
 David Sterba <dsterba@suse.com>, linux-kernel@vger.kernel.org
References: <cover.1710769876.git.tavianator@tavianator.com>
 <477327c2e21e253b56261f504a91603419bb167a.1710769876.git.tavianator@tavianator.com>
From: Qu Wenruo <wqu@suse.com>
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In-Reply-To: <477327c2e21e253b56261f504a91603419bb167a.1710769876.git.tavianator@tavianator.com>
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在 2024/3/19 00:26, Tavian Barnes 写道:
> We are clearing the bit and waking up any waiters in two different
> places.  Factor that code out into a static helper function.
> 
> Signed-off-by: Tavian Barnes <tavianator@tavianator.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu
> ---
>   fs/btrfs/extent_io.c | 15 +++++++++------
>   1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 61594eaf1f89..46173dcfde4f 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -4270,6 +4270,13 @@ void set_extent_buffer_uptodate(struct extent_buffer *eb)
>   	}
>   }
>   
> +static void clear_extent_buffer_reading(struct extent_buffer *eb)
> +{
> +	clear_bit(EXTENT_BUFFER_READING, &eb->bflags);
> +	smp_mb__after_atomic();
> +	wake_up_bit(&eb->bflags, EXTENT_BUFFER_READING);
> +}
> +
>   static void end_bbio_meta_read(struct btrfs_bio *bbio)
>   {
>   	struct extent_buffer *eb = bbio->private;
> @@ -4304,9 +4311,7 @@ static void end_bbio_meta_read(struct btrfs_bio *bbio)
>   		bio_offset += len;
>   	}
>   
> -	clear_bit(EXTENT_BUFFER_READING, &eb->bflags);
> -	smp_mb__after_atomic();
> -	wake_up_bit(&eb->bflags, EXTENT_BUFFER_READING);
> +	clear_extent_buffer_reading(eb);
>   	free_extent_buffer(eb);
>   
>   	bio_put(&bbio->bio);
> @@ -4340,9 +4345,7 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
>   	 * will now be set, and we shouldn't read it in again.
>   	 */
>   	if (unlikely(test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))) {
> -		clear_bit(EXTENT_BUFFER_READING, &eb->bflags);
> -		smp_mb__after_atomic();
> -		wake_up_bit(&eb->bflags, EXTENT_BUFFER_READING);
> +		clear_extent_buffer_reading(eb);
>   		return 0;
>   	}
>