From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0329333F3 for ; Tue, 19 Aug 2025 01:15:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755566135; cv=none; b=E3kr050iuAKgcq7jdp3A239KZh8uBM71gr5qKeAhbzMjxtkW3BdZF7kZy7WLmJVS7YhIYmVmhiw/znSb/ZDD3FXKvMzdspHZxHLX5IGBqO6wCZkUu+BVGLF1O+OHSn1kVJVW1/BSkjqpDklrg8OQH/tN3Wf3Bz++aNkVKEcnFmA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755566135; c=relaxed/simple; bh=cj3uzMere4UcnswI6Fi2EHvAFWLFaJzEbwXh6OqrvZY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WOc/dFCFAcuGn/su3uHEqVsMjrXbKCG6pfOFTue5DIMnt0vhp/bxANxXBavsa6Ha0LAsw0cClCC8BQawJf0CulJ2DX8A7LRYwPafKbj0pwjtKrMc6/q9wQeWD84JrgUJRCUmhMuieH0EsbC5Rr2ojtKK7pvB5sUrCbSvxPP+TI0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rmPVLTBA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rmPVLTBA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33891C4CEEB; Tue, 19 Aug 2025 01:15:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755566133; bh=cj3uzMere4UcnswI6Fi2EHvAFWLFaJzEbwXh6OqrvZY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rmPVLTBAdRLKP1yULJRf5WTyvyOk6SzfcOtYQqWuPr6P16EfpdT36womHOe3/Hm5m tn1dGd4qZKdBZBkq4YoqNQeNg+4n2ZM+7RQ4rM8bqkR5t9AROz09Y59+xI8AKJfPfI diZg0SpOBuWhF+iN8UxIXn8U1p3FJ4YM19EKVO11N1Hb6EAGf5V5qzT0dVD4qKcqjg pdvNC+lTGyW52p9WZSyriENABvotdxoDfxAZIMxIT48NDciE/CuGID5UD3RT3XHpt5 75hB53j5XI6lL7A+5MYCOu/d8yPKwsxwmXRNthFbqyAz7y8TKlk1JwBnetveGB23Zo 5TVp0mtwUltlg== From: Sasha Levin To: stable@vger.kernel.org Cc: Filipe Manana , Boris Burkov , David Sterba , Sasha Levin Subject: [PATCH 6.16.y 1/4] btrfs: reorganize logic at free_extent_buffer() for better readability Date: Mon, 18 Aug 2025 21:15:28 -0400 Message-ID: <20250819011531.242846-1-sashal@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <2025081814-monsoon-supermom-44bb@gregkh> References: <2025081814-monsoon-supermom-44bb@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Filipe Manana [ Upstream commit 71c086b30d4373a01bd5627f54516a72891a026a ] It's hard to read the logic to break out of the while loop since it's a very long expression consisting of a logical or of two composite expressions, each one composed by a logical and. Further each one is also testing for the EXTENT_BUFFER_UNMAPPED bit, making it more verbose than necessary. So change from this: if ((!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && refs <= 3) || (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && refs == 1)) break; To this: if (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags)) { if (refs == 1) break; } else if (refs <= 3) { break; } At least on x86_64 using gcc 9.3.0, this doesn't change the object size. Reviewed-by: Boris Burkov Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Stable-dep-of: ad580dfa388f ("btrfs: fix subpage deadlock in try_release_subpage_extent_buffer()") Signed-off-by: Sasha Levin --- fs/btrfs/extent_io.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 1dc931c4937f..8590f8a4a139 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3486,10 +3486,13 @@ void free_extent_buffer(struct extent_buffer *eb) refs = atomic_read(&eb->refs); while (1) { - if ((!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && refs <= 3) - || (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && - refs == 1)) + if (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags)) { + if (refs == 1) + break; + } else if (refs <= 3) { break; + } + if (atomic_try_cmpxchg(&eb->refs, &refs, refs - 1)) return; } -- 2.50.1