From: Stefan Brüns Date: Sun, 5 Feb 2017 14:57:59 +0000 (-0200) Subject: cxusb: Use a dma capable buffer also for reading X-Git-Tag: C0P2-H0.0--20200415~9317 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=fb00319317c152bf3528df13a54c28bf8c5daa55;p=linux.git 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 Signed-off-by: Mauro Carvalho Chehab Cc: Ben Hutchings Cc: Brad Spengler Signed-off-by: Greg Kroah-Hartman --- 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;