lkml.org 
[lkml]   [2016]   [Oct]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH v2 .1 28/31] cpia2_usb: don't use stack for DMA
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 <mchehab@osg.samsung.com>

--

v2.1: As pointed by Kosuke Tatsukawa, I forgot to replace "registers" var
to "buf" at one of the usb_control_msg() calls.

diff --git a/drivers/media/usb/cpia2/cpia2_usb.c b/drivers/media/usb/cpia2/cpia2_usb.c
index 13620cdf0599..e9100a235831 100644
--- a/drivers/media/usb/cpia2/cpia2_usb.c
+++ b/drivers/media/usb/cpia2/cpia2_usb.c
@@ -545,18 +545,30 @@ 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,
start, /* value */
0, /* index */
- registers, /* buffer */
+ buf, /* 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;
}

/******************************************************************************
\
 
 \ /
  Last update: 2016-10-12 04:19    [W:0.097 / U:0.876 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site