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 D8EC418B00 for ; Mon, 9 Oct 2023 13:08:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="h4HE7m83" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B638C433C9; Mon, 9 Oct 2023 13:08:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696856907; bh=bf0UpMAOpeBUxMQ9QBsqW3gNY2a04CkVGpYvmsRkLEI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=h4HE7m832YXrre4KfODC8fQu1H3JYNr0YTqNdvlHFJf+jjYfSHn5uUapp2eoLtvR+ U5DlBfY7vy9n8Ce5xoRv8jENPwdvg/deloxZBAS65Y9lEt2wokp/JFyhmbBLhcAHWQ hWdA0oHkziXW2snXo0pas6UQa2Gp7greRUd8ewco= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jason Wang , Stefano Garzarella , "David S. Miller" Subject: [PATCH 6.5 030/163] vringh: dont use vringh_kiov_advance() in vringh_iov_xfer() Date: Mon, 9 Oct 2023 14:59:54 +0200 Message-ID: <20231009130124.836061898@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130124.021290599@linuxfoundation.org> References: <20231009130124.021290599@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 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefano Garzarella commit 7aed44babc7f97e82b38e9a68515e699692cc100 upstream. In the while loop of vringh_iov_xfer(), `partlen` could be 0 if one of the `iov` has 0 lenght. In this case, we should skip the iov and go to the next one. But calling vringh_kiov_advance() with 0 lenght does not cause the advancement, since it returns immediately if asked to advance by 0 bytes. Let's restore the code that was there before commit b8c06ad4d67d ("vringh: implement vringh_kiov_advance()"), avoiding using vringh_kiov_advance(). Fixes: b8c06ad4d67d ("vringh: implement vringh_kiov_advance()") Cc: stable@vger.kernel.org Reported-by: Jason Wang Signed-off-by: Stefano Garzarella Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/vringh.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -123,8 +123,18 @@ static inline ssize_t vringh_iov_xfer(st done += partlen; len -= partlen; ptr += partlen; + iov->consumed += partlen; + iov->iov[iov->i].iov_len -= partlen; + iov->iov[iov->i].iov_base += partlen; - vringh_kiov_advance(iov, partlen); + if (!iov->iov[iov->i].iov_len) { + /* Fix up old iov element then increment. */ + iov->iov[iov->i].iov_len = iov->consumed; + iov->iov[iov->i].iov_base -= iov->consumed; + + iov->consumed = 0; + iov->i++; + } } return done; }