| From | Mauro Carvalho Chehab <> | Subject | [PATCH v2 29/31] s2255drv: don't use stack for DMA | Date | Tue, 11 Oct 2016 07:09:44 -0300 |
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From: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
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> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> --- drivers/media/usb/s2255/s2255drv.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/media/usb/s2255/s2255drv.c b/drivers/media/usb/s2255/s2255drv.c index c3a0e87066eb..f7bb78c1873c 100644 --- a/drivers/media/usb/s2255/s2255drv.c +++ b/drivers/media/usb/s2255/s2255drv.c @@ -1901,19 +1901,30 @@ static long s2255_vendor_req(struct s2255_dev *dev, unsigned char Request, s32 TransferBufferLength, int bOut) { int r; + unsigned char *buf; + + buf = kmalloc(TransferBufferLength, GFP_KERNEL); + if (!buf) + return -ENOMEM; + if (!bOut) { r = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), Request, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, - Value, Index, TransferBuffer, + Value, Index, buf, TransferBufferLength, HZ * 5); + + if (r >= 0) + memcpy(TransferBuffer, buf, TransferBufferLength); } else { + memcpy(buf, TransferBuffer, TransferBufferLength); r = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0), Request, USB_TYPE_VENDOR | USB_RECIP_DEVICE, - Value, Index, TransferBuffer, + Value, Index, buf, TransferBufferLength, HZ * 5); } + kfree(buf); return r; } -- 2.7.4
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