The USB control messages require DMA to work. We cannot pass
a stack-allocated buffer, as it is not warranted that the
stack would be into a DMA enabled area.

Reviewed-By: Patrick Boettcher <patrick.boettc...@posteo.de>
Signed-off-by: Mauro Carvalho Chehab <mche...@s-opensource.com>
---
 drivers/media/usb/dvb-usb/dibusb-common.c | 107 +++++++++++++++++++++++-------
 drivers/media/usb/dvb-usb/dibusb.h        |   3 +
 2 files changed, 85 insertions(+), 25 deletions(-)

diff --git a/drivers/media/usb/dvb-usb/dibusb-common.c 
b/drivers/media/usb/dvb-usb/dibusb-common.c
index 4b08c2a47ae2..951f3dac9082 100644
--- a/drivers/media/usb/dvb-usb/dibusb-common.c
+++ b/drivers/media/usb/dvb-usb/dibusb-common.c
@@ -63,72 +63,117 @@ EXPORT_SYMBOL(dibusb_pid_filter_ctrl);
 
 int dibusb_power_ctrl(struct dvb_usb_device *d, int onoff)
 {
-       u8 b[3];
+       u8 *b;
        int ret;
+
+       b = kmalloc(3, GFP_KERNEL);
+       if (!b)
+               return -ENOMEM;
+
        b[0] = DIBUSB_REQ_SET_IOCTL;
        b[1] = DIBUSB_IOCTL_CMD_POWER_MODE;
        b[2] = onoff ? DIBUSB_IOCTL_POWER_WAKEUP : DIBUSB_IOCTL_POWER_SLEEP;
-       ret = dvb_usb_generic_write(d,b,3);
+
+       ret = dvb_usb_generic_write(d, b, 3);
+
+       kfree(b);
+
        msleep(10);
+
        return ret;
 }
 EXPORT_SYMBOL(dibusb_power_ctrl);
 
 int dibusb2_0_streaming_ctrl(struct dvb_usb_adapter *adap, int onoff)
 {
-       u8 b[3] = { 0 };
        int ret;
+       u8 *b;
+
+       b = kmalloc(3, GFP_KERNEL);
+       if (!b)
+               return -ENOMEM;
 
        if ((ret = dibusb_streaming_ctrl(adap,onoff)) < 0)
-               return ret;
+               goto ret;
 
        if (onoff) {
                b[0] = DIBUSB_REQ_SET_STREAMING_MODE;
                b[1] = 0x00;
-               if ((ret = dvb_usb_generic_write(adap->dev,b,2)) < 0)
-                       return ret;
+               ret = dvb_usb_generic_write(adap->dev, b, 2);
+               if (ret  < 0)
+                       goto ret;
        }
 
        b[0] = DIBUSB_REQ_SET_IOCTL;
        b[1] = onoff ? DIBUSB_IOCTL_CMD_ENABLE_STREAM : 
DIBUSB_IOCTL_CMD_DISABLE_STREAM;
-       return dvb_usb_generic_write(adap->dev,b,3);
+       ret = dvb_usb_generic_write(adap->dev, b, 3);
+
+ret:
+       kfree(b);
+       return ret;
 }
 EXPORT_SYMBOL(dibusb2_0_streaming_ctrl);
 
 int dibusb2_0_power_ctrl(struct dvb_usb_device *d, int onoff)
 {
-       if (onoff) {
-               u8 b[3] = { DIBUSB_REQ_SET_IOCTL, DIBUSB_IOCTL_CMD_POWER_MODE, 
DIBUSB_IOCTL_POWER_WAKEUP };
-               return dvb_usb_generic_write(d,b,3);
-       } else
+       u8 *b;
+       int ret;
+
+       if (!onoff)
                return 0;
+
+       b = kmalloc(3, GFP_KERNEL);
+       if (!b)
+               return -ENOMEM;
+
+       b[0] = DIBUSB_REQ_SET_IOCTL;
+       b[1] = DIBUSB_IOCTL_CMD_POWER_MODE;
+       b[2] = DIBUSB_IOCTL_POWER_WAKEUP;
+
+       ret = dvb_usb_generic_write(d, b, 3);
+
+       kfree(b);
+
+       return ret;
 }
 EXPORT_SYMBOL(dibusb2_0_power_ctrl);
 
 static int dibusb_i2c_msg(struct dvb_usb_device *d, u8 addr,
                          u8 *wbuf, u16 wlen, u8 *rbuf, u16 rlen)
 {
-       u8 sndbuf[MAX_XFER_SIZE]; /* lead(1) devaddr,direction(1) addr(2) 
data(wlen) (len(2) (when reading)) */
+       u8 *sndbuf;
+       int ret, wo, len;
+
        /* write only ? */
-       int wo = (rbuf == NULL || rlen == 0),
-               len = 2 + wlen + (wo ? 0 : 2);
+       wo = (rbuf == NULL || rlen == 0);
 
-       if (4 + wlen > sizeof(sndbuf)) {
+       len = 2 + wlen + (wo ? 0 : 2);
+
+       sndbuf = kmalloc(MAX_XFER_SIZE, GFP_KERNEL);
+       if (!sndbuf)
+               return -ENOMEM;
+
+       if (4 + wlen > MAX_XFER_SIZE) {
                warn("i2c wr: len=%d is too big!\n", wlen);
-               return -EOPNOTSUPP;
+               ret = -EOPNOTSUPP;
+               goto ret;
        }
 
        sndbuf[0] = wo ? DIBUSB_REQ_I2C_WRITE : DIBUSB_REQ_I2C_READ;
        sndbuf[1] = (addr << 1) | (wo ? 0 : 1);
 
-       memcpy(&sndbuf[2],wbuf,wlen);
+       memcpy(&sndbuf[2], wbuf, wlen);
 
        if (!wo) {
-               sndbuf[wlen+2] = (rlen >> 8) & 0xff;
-               sndbuf[wlen+3] = rlen & 0xff;
+               sndbuf[wlen + 2] = (rlen >> 8) & 0xff;
+               sndbuf[wlen + 3] = rlen & 0xff;
        }
 
-       return dvb_usb_generic_rw(d,sndbuf,len,rbuf,rlen,0);
+       ret = dvb_usb_generic_rw(d, sndbuf, len, rbuf, rlen, 0);
+
+ret:
+       kfree(sndbuf);
+       return ret;
 }
 
 /*
@@ -320,11 +365,23 @@ EXPORT_SYMBOL(rc_map_dibusb_table);
 
 int dibusb_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
-       u8 key[5],cmd = DIBUSB_REQ_POLL_REMOTE;
-       dvb_usb_generic_rw(d,&cmd,1,key,5,0);
-       dvb_usb_nec_rc_key_to_event(d,key,event,state);
-       if (key[0] != 0)
-               deb_info("key: %*ph\n", 5, key);
+       u8 *buf;
+
+       buf = kmalloc(5, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+
+       buf[0] = DIBUSB_REQ_POLL_REMOTE;
+
+       dvb_usb_generic_rw(d, buf, 1, buf, 5, 0);
+
+       dvb_usb_nec_rc_key_to_event(d, buf, event, state);
+
+       if (buf[0] != 0)
+               deb_info("key: %*ph\n", 5, buf);
+
+       kfree(buf);
+
        return 0;
 }
 EXPORT_SYMBOL(dibusb_rc_query);
diff --git a/drivers/media/usb/dvb-usb/dibusb.h 
b/drivers/media/usb/dvb-usb/dibusb.h
index 3f82163d8ab8..697be2a17ade 100644
--- a/drivers/media/usb/dvb-usb/dibusb.h
+++ b/drivers/media/usb/dvb-usb/dibusb.h
@@ -96,6 +96,9 @@
 #define DIBUSB_IOCTL_CMD_ENABLE_STREAM 0x01
 #define DIBUSB_IOCTL_CMD_DISABLE_STREAM        0x02
 
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE  64
+
 struct dibusb_state {
        struct dib_fe_xfer_ops ops;
        int mt2060_present;
-- 
2.7.4


Reply via email to