[PATCH 3.2 10/95] [media] dvb-usb-firmware: don't do DMA on stack

From: Ben Hutchings
Date: Sun Jul 16 2017 - 11:05:40 EST


3.2.91-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Stefan BrÃns <stefan.bruens@xxxxxxxxxxxxxx>

commit 67b0503db9c29b04eadfeede6bebbfe5ddad94ef upstream.

The buffer allocation for the firmware data was changed in
commit 43fab9793c1f ("[media] dvb-usb: don't use stack for firmware load")
but the same applies for the reset value.

Fixes: 43fab9793c1f ("[media] dvb-usb: don't use stack for firmware load")
Signed-off-by: Stefan BrÃns <stefan.bruens@xxxxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/media/dvb/dvb-usb/dvb-usb-firmware.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)

--- a/drivers/media/dvb/dvb-usb/dvb-usb-firmware.c
+++ b/drivers/media/dvb/dvb-usb/dvb-usb-firmware.c
@@ -36,16 +36,18 @@ static int usb_cypress_writemem(struct u
int usb_cypress_load_firmware(struct usb_device *udev, const struct firmware *fw, int type)
{
struct hexline *hx;
- u8 reset;
- int ret,pos=0;
+ u8 *buf;
+ int ret, pos = 0;
+ u16 cpu_cs_register = cypress[type].cpu_cs_register;

- hx = kmalloc(sizeof(*hx), GFP_KERNEL);
- if (!hx)
+ buf = kmalloc(sizeof(*hx), GFP_KERNEL);
+ if (!buf)
return -ENOMEM;
+ hx = (struct hexline *)buf;

/* stop the CPU */
- reset = 1;
- if ((ret = usb_cypress_writemem(udev,cypress[type].cpu_cs_register,&reset,1)) != 1)
+ buf[0] = 1;
+ if (usb_cypress_writemem(udev, cpu_cs_register, buf, 1) != 1)
err("could not stop the USB controller CPU.");

while ((ret = dvb_usb_get_hexline(fw, hx, &pos)) > 0) {
@@ -62,21 +64,21 @@ int usb_cypress_load_firmware(struct usb
}
if (ret < 0) {
err("firmware download failed at %d with %d",pos,ret);
- kfree(hx);
+ kfree(buf);
return ret;
}

if (ret == 0) {
/* restart the CPU */
- reset = 0;
- if (ret || usb_cypress_writemem(udev,cypress[type].cpu_cs_register,&reset,1) != 1) {
+ buf[0] = 0;
+ if (usb_cypress_writemem(udev, cpu_cs_register, buf, 1) != 1) {
err("could not restart the USB controller CPU.");
ret = -EINVAL;
}
} else
ret = -EIO;

- kfree(hx);
+ kfree(buf);

return ret;
}