diff options
| author | Stefan Brüns <stefan.bruens@rwth-aachen.de> | 2017-02-05 12:57:59 -0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-21 09:31:24 +0200 |
| commit | fb00319317c152bf3528df13a54c28bf8c5daa55 (patch) | |
| tree | 3678005dc4b516587be3b7a5ad576667d4153fe8 /drivers | |
| parent | 28d1e8b7ef81d254583f68627095f8a85e39597d (diff) | |
cxusb: Use a dma capable buffer also for reading
commit 3f190e3aec212fc8c61e202c51400afa7384d4bc upstream.
Commit 17ce039b4e54 ("[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: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/usb/dvb-usb/cxusb.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/media/usb/dvb-usb/cxusb.c b/drivers/media/usb/dvb-usb/cxusb.c index 243403081fa5..9fd43a37154c 100644 --- a/drivers/media/usb/dvb-usb/cxusb.c +++ b/drivers/media/usb/dvb-usb/cxusb.c @@ -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; |