From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2897FC55186 for ; Thu, 23 Apr 2020 23:11:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1405320784 for ; Thu, 23 Apr 2020 23:11:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729229AbgDWXLU (ORCPT ); Thu, 23 Apr 2020 19:11:20 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:50270 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728575AbgDWXGw (ORCPT ); Thu, 23 Apr 2020 19:06:52 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jRkvZ-0004nR-IX; Fri, 24 Apr 2020 00:06:41 +0100 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1jRkvV-00E6vx-Ln; Fri, 24 Apr 2020 00:06:37 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Jonathan Cameron" , "Greg Kroah-Hartman" , "Lars-Peter Clausen" , "=?UTF-8?q?Lars=20M=C3=B6llendorf?=" Date: Fri, 24 Apr 2020 00:06:43 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 176/245] iio: buffer: align the size of scan bytes to size of the largest element In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.83-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Lars Möllendorf commit 883f616530692d81cb70f8a32d85c0d2afc05f69 upstream. Previous versions of `iio_compute_scan_bytes` only aligned each element to its own length (i.e. its own natural alignment). Because multiple consecutive sets of scan elements are buffered this does not work in case the computed scan bytes do not align with the natural alignment of the first scan element in the set. This commit fixes this by aligning the scan bytes to the natural alignment of the largest scan element in the set. Fixes: 959d2952d124 ("staging:iio: make iio_sw_buffer_preenable much more general.") Signed-off-by: Lars Möllendorf Reviewed-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/iio/industrialio-buffer.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -478,7 +478,7 @@ static int iio_compute_scan_bytes(struct { const struct iio_chan_spec *ch; unsigned bytes = 0; - int length, i; + int length, i, largest = 0; /* How much space will the demuxed element take? */ for_each_set_bit(i, mask, @@ -491,6 +491,7 @@ static int iio_compute_scan_bytes(struct length = ch->scan_type.storagebits / 8; bytes = ALIGN(bytes, length); bytes += length; + largest = max(largest, length); } if (timestamp) { ch = iio_find_channel_from_si(indio_dev, @@ -502,7 +503,10 @@ static int iio_compute_scan_bytes(struct length = ch->scan_type.storagebits / 8; bytes = ALIGN(bytes, length); bytes += length; + largest = max(largest, length); } + + bytes = ALIGN(bytes, largest); return bytes; }