From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754686AbdJINNe (ORCPT ); Mon, 9 Oct 2017 09:13:34 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42029 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754283AbdJIMpA (ORCPT ); Mon, 9 Oct 2017 08:45:00 -0400 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, "Pengfei Wang" , "Mauro Carvalho Chehab" , "Steven Toth" Date: Mon, 09 Oct 2017 13:44:24 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 132/192] [media] saa7164: fix double fetch PCIe access condition In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.49-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Steven Toth commit 6fb05e0dd32e566facb96ea61a48c7488daa5ac3 upstream. Avoid a double fetch by reusing the values from the prior transfer. Originally reported via https://bugzilla.kernel.org/show_bug.cgi?id=195559 Thanks to Pengfei Wang for reporting. Signed-off-by: Steven Toth Reported-by: Pengfei Wang Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Ben Hutchings --- drivers/media/pci/saa7164/saa7164-bus.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-) --- a/drivers/media/pci/saa7164/saa7164-bus.c +++ b/drivers/media/pci/saa7164/saa7164-bus.c @@ -393,11 +393,11 @@ int saa7164_bus_get(struct saa7164_dev * msg_tmp.size = le16_to_cpu((__force __le16)msg_tmp.size); msg_tmp.command = le32_to_cpu((__force __le32)msg_tmp.command); msg_tmp.controlselector = le16_to_cpu((__force __le16)msg_tmp.controlselector); + memcpy(msg, &msg_tmp, sizeof(*msg)); /* No need to update the read positions, because this was a peek */ /* If the caller specifically want to peek, return */ if (peekonly) { - memcpy(msg, &msg_tmp, sizeof(*msg)); goto peekout; } @@ -442,21 +442,15 @@ int saa7164_bus_get(struct saa7164_dev * space_rem = bus->m_dwSizeGetRing - curr_grp; if (space_rem < sizeof(*msg)) { - /* msg wraps around the ring */ - memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, space_rem); - memcpy_fromio((u8 *)msg + space_rem, bus->m_pdwGetRing, - sizeof(*msg) - space_rem); if (buf) memcpy_fromio(buf, bus->m_pdwGetRing + sizeof(*msg) - space_rem, buf_size); } else if (space_rem == sizeof(*msg)) { - memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg)); if (buf) memcpy_fromio(buf, bus->m_pdwGetRing, buf_size); } else { /* Additional data wraps around the ring */ - memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg)); if (buf) { memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp + sizeof(*msg), space_rem - sizeof(*msg)); @@ -469,15 +463,10 @@ int saa7164_bus_get(struct saa7164_dev * } else { /* No wrapping */ - memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg)); if (buf) memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp + sizeof(*msg), buf_size); } - /* Convert from little endian to CPU */ - msg->size = le16_to_cpu((__force __le16)msg->size); - msg->command = le32_to_cpu((__force __le32)msg->command); - msg->controlselector = le16_to_cpu((__force __le16)msg->controlselector); /* Update the read positions, adjusting the ring */ saa7164_writel(bus->m_dwGetReadPos, new_grp);