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 C9E6F339B4 for ; Mon, 9 Oct 2023 13:42:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RAgwsPzU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E9CCEC433CD; Mon, 9 Oct 2023 13:42:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696858953; bh=IkBBfBHdIUb0IcnIxYaw4dhWoPL6i3nR2XwSqIpmdIw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RAgwsPzU1KxWQzpbMQU3FPeNR5Dqj1wRColfKPMwfp6prqyMBlaH/0MUmB6GOieBd AJHFK0mqQJov6UlNnVk7BTABnI4EjLN0Lx6JGKadk3LXSs7bhpxhRL0xrYrlG89/vG g7XlVLA/Q+HINdpCf6u7A0lUr3r2f/wpdSSdVOgc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hans Verkuil , David Hildenbrand , Yikebaer Aizezi , Sasha Levin Subject: [PATCH 5.10 124/226] media: vb2: frame_vector.c: replace WARN_ONCE with a comment Date: Mon, 9 Oct 2023 15:01:25 +0200 Message-ID: <20231009130130.016752643@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130126.697995596@linuxfoundation.org> References: <20231009130126.697995596@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hans Verkuil [ Upstream commit 735de5caf79e06cc9fb96b1b4f4974674ae3e917 ] The WARN_ONCE was issued also in cases that had nothing to do with VM_IO (e.g. if the start address was just a random value and uaccess fails with -EFAULT). There are no reports of WARN_ONCE being issued for actual VM_IO cases, so just drop it and instead add a note to the comment before the function. Signed-off-by: Hans Verkuil Reviewed-by: David Hildenbrand Reported-by: Yikebaer Aizezi Signed-off-by: Sasha Levin --- mm/frame_vector.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/frame_vector.c b/mm/frame_vector.c index 0e589a9a88012..1cd81d38ad2d0 100644 --- a/mm/frame_vector.c +++ b/mm/frame_vector.c @@ -29,6 +29,10 @@ * different type underlying the specified range of virtual addresses. * When the function isn't able to map a single page, it returns error. * + * Note that get_vaddr_frames() cannot follow VM_IO mappings. It used + * to be able to do that, but that could (racily) return non-refcounted + * pfns. + * * This function takes care of grabbing mmap_lock as necessary. */ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, @@ -77,8 +81,6 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, goto out; } - /* This used to (racily) return non-refcounted pfns. Let people know */ - WARN_ONCE(1, "get_vaddr_frames() cannot follow VM_IO mapping"); vec->nr_frames = 0; out: -- 2.40.1