Commit fb003193 authored by Stefan Brüns's avatar Stefan Brüns Committed by Greg Kroah-Hartman

cxusb: Use a dma capable buffer also for reading

commit 3f190e3a upstream.

Commit 17ce039b ("[media] cxusb: don't do DMA on stack")
added a kmalloc'ed bounce buffer for writes, but missed to do the same
for reads. As the read only happens after the write is finished, we can
reuse the same buffer.

As dvb_usb_generic_rw handles a read length of 0 by itself, avoid calling
it using the dvb_usb_generic_read wrapper function.
Signed-off-by: default avatarStefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 28d1e8b7
......@@ -59,23 +59,24 @@ static int cxusb_ctrl_msg(struct dvb_usb_device *d,
u8 cmd, u8 *wbuf, int wlen, u8 *rbuf, int rlen)
{
struct cxusb_state *st = d->priv;
int ret, wo;
int ret;
if (1 + wlen > MAX_XFER_SIZE) {
warn("i2c wr: len=%d is too big!\n", wlen);
return -EOPNOTSUPP;
}
wo = (rbuf == NULL || rlen == 0); /* write-only */
if (rlen > MAX_XFER_SIZE) {
warn("i2c rd: len=%d is too big!\n", rlen);
return -EOPNOTSUPP;
}
mutex_lock(&d->data_mutex);
st->data[0] = cmd;
memcpy(&st->data[1], wbuf, wlen);
if (wo)
ret = dvb_usb_generic_write(d, st->data, 1 + wlen);
else
ret = dvb_usb_generic_rw(d, st->data, 1 + wlen,
rbuf, rlen, 0);
ret = dvb_usb_generic_rw(d, st->data, 1 + wlen, st->data, rlen, 0);
if (!ret && rbuf && rlen)
memcpy(rbuf, st->data, rlen);
mutex_unlock(&d->data_mutex);
return ret;
......
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