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authorStefan Brüns <stefan.bruens@rwth-aachen.de>2017-02-05 12:57:59 -0200
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2017-02-08 11:52:40 -0200
commit3f190e3aec212fc8c61e202c51400afa7384d4bc (patch)
tree56edab612463b64d0cb0428820c1074e6e0ce3d8 /drivers/media
parent69d3973af1acd4c0989ec8218c05f12d303cd7cf (diff)
[media] cxusb: Use a dma capable buffer also for reading
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>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/usb/dvb-usb/cxusb.c15
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 5d7b4eaa6a3c..51620e02292f 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;

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