Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753623AbcJKKPu (ORCPT ); Tue, 11 Oct 2016 06:15:50 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:56807 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752840AbcJKKLj (ORCPT ); Tue, 11 Oct 2016 06:11:39 -0400 From: Mauro Carvalho Chehab To: Linux Media Mailing List Cc: Mauro Carvalho Chehab , Mauro Carvalho Chehab , Andy Lutomirski , Johannes Stezenbach , Jiri Kosina , Patrick Boettcher , Linux Kernel Mailing List , Andy Lutomirski , Michael Krufky , Mauro Carvalho Chehab , =?UTF-8?q?J=C3=B6rg=20Otte?= , Hans Verkuil , Kosuke Tatsukawa , Wolfram Sang , Mauro Carvalho Chehab Subject: [PATCH v2 28/31] cpia2_usb: don't use stack for DMA Date: Tue, 11 Oct 2016 07:09:43 -0300 Message-Id: X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2315 Lines: 85 From: Mauro Carvalho Chehab The USB control messages require DMA to work. We cannot pass a stack-allocated buffer, as it is not warranted that the stack would be into a DMA enabled area. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/cpia2/cpia2_usb.c | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) diff --git a/drivers/media/usb/cpia2/cpia2_usb.c b/drivers/media/usb/cpia2/cpia2_usb.c index 13620cdf0599..417d683b237d 100644 --- a/drivers/media/usb/cpia2/cpia2_usb.c +++ b/drivers/media/usb/cpia2/cpia2_usb.c @@ -545,10 +545,19 @@ static void free_sbufs(struct camera_data *cam) static int write_packet(struct usb_device *udev, u8 request, u8 * registers, u16 start, size_t size) { + unsigned char *buf; + int ret; + if (!registers || size <= 0) return -EINVAL; - return usb_control_msg(udev, + buf = kmalloc(size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + memcpy(buf, registers, size); + + ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), request, USB_TYPE_VENDOR | USB_RECIP_DEVICE, @@ -557,6 +566,9 @@ static int write_packet(struct usb_device *udev, registers, /* buffer */ size, HZ); + + kfree(buf); + return ret; } /**************************************************************************** @@ -567,18 +579,32 @@ static int write_packet(struct usb_device *udev, static int read_packet(struct usb_device *udev, u8 request, u8 * registers, u16 start, size_t size) { + unsigned char *buf; + int ret; + if (!registers || size <= 0) return -EINVAL; - return usb_control_msg(udev, + buf = kmalloc(size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), request, USB_DIR_IN|USB_TYPE_VENDOR|USB_RECIP_DEVICE, start, /* value */ 0, /* index */ - registers, /* buffer */ + buf, /* buffer */ size, HZ); + + if (ret >= 0) + memcpy (registers, buf, size); + + kfree(buf); + + return ret; } /****************************************************************************** -- 2.7.4