dw2102: don't do DMA on stack

commit 606142af57dad981b78707234cfbd15f9f7b7125 upstream.

On Kernel 4.9, WARNINGs about doing DMA on stack are hit at
the dw2102 driver: one in su3000_power_ctrl() and the other in tt_s2_4600_frontend_attach().

Both were due to the use of buffers on the stack as parameters to
dvb_usb_generic_rw() and the resulting attempt to do DMA with them.

The device was non-functional as a result.

So, switch this driver over to use a buffer within the device state
structure, as has been done with other DVB-USB drivers.

Tested with TechnoTrend TT-connect S2-4600.

[mchehab@osg.samsung.com: fixed a warning at su3000_i2c_transfer() that
 state var were dereferenced before check 'd']
Signed-off-by: Jonathan McDowell <noodles@earth.li>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/usb/dvb-usb/dw2102.c b/drivers/media/usb/dvb-usb/dw2102.c
index 2c720cb..c3e6734 100644 (file)
--- a/drivers/media/usb/dvb-usb/dw2102.c
+++ b/drivers/media/usb/dvb-usb/dw2102.c
@@ -68,6 +68,7 @@
 struct dw2102_state {
        u8 initialized;
        u8 last_lock;
+       u8 data[MAX_XFER_SIZE + 4];
        struct i2c_client *i2c_client_demod;
        struct i2c_client *i2c_client_tuner;
 
@@ -662,62 +663,72 @@ static int su3000_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg msg[],
                                                                int num)
 {
        struct dvb_usb_device *d = i2c_get_adapdata(adap);
-       u8 obuf[0x40], ibuf[0x40];
+       struct dw2102_state *state;
 
        if (!d)
                return -ENODEV;
+
+       state = d->priv;
+
        if (mutex_lock_interruptible(&d->i2c_mutex) < 0)
                return -EAGAIN;
+       if (mutex_lock_interruptible(&d->data_mutex) < 0) {
+               mutex_unlock(&d->i2c_mutex);
+               return -EAGAIN;
+       }
 
        switch (num) {
        case 1:
                switch (msg[0].addr) {
                case SU3000_STREAM_CTRL:
-                       obuf[0] = msg[0].buf[0] + 0x36;
-                       obuf[1] = 3;
-                       obuf[2] = 0;
-                       if (dvb_usb_generic_rw(d, obuf, 3, ibuf, 0, 0) < 0)
+                       state->data[0] = msg[0].buf[0] + 0x36;
+                       state->data[1] = 3;
+                       state->data[2] = 0;
+                       if (dvb_usb_generic_rw(d, state->data, 3,
+                                       state->data, 0, 0) < 0)
                                err("i2c transfer failed.");
                        break;
                case DW2102_RC_QUERY:
-                       obuf[0] = 0x10;
-                       if (dvb_usb_generic_rw(d, obuf, 1, ibuf, 2, 0) < 0)
+                       state->data[0] = 0x10;
+                       if (dvb_usb_generic_rw(d, state->data, 1,
+                                       state->data, 2, 0) < 0)
                                err("i2c transfer failed.");
-                       msg[0].buf[1] = ibuf[0];
-                       msg[0].buf[0] = ibuf[1];
+                       msg[0].buf[1] = state->data[0];
+                       msg[0].buf[0] = state->data[1];
                        break;
                default:
                        /* always i2c write*/
-                       obuf[0] = 0x08;
-                       obuf[1] = msg[0].addr;
-                       obuf[2] = msg[0].len;
+                       state->data[0] = 0x08;
+                       state->data[1] = msg[0].addr;
+                       state->data[2] = msg[0].len;
 
-                       memcpy(&obuf[3], msg[0].buf, msg[0].len);
+                       memcpy(&state->data[3], msg[0].buf, msg[0].len);
 
-                       if (dvb_usb_generic_rw(d, obuf, msg[0].len + 3,
-                                               ibuf, 1, 0) < 0)
+                       if (dvb_usb_generic_rw(d, state->data, msg[0].len + 3,
+                                               state->data, 1, 0) < 0)
                                err("i2c transfer failed.");
 
                }
                break;
        case 2:
                /* always i2c read */
-               obuf[0] = 0x09;
-               obuf[1] = msg[0].len;
-               obuf[2] = msg[1].len;
-               obuf[3] = msg[0].addr;
-               memcpy(&obuf[4], msg[0].buf, msg[0].len);
-
-               if (dvb_usb_generic_rw(d, obuf, msg[0].len + 4,
-                                       ibuf, msg[1].len + 1, 0) < 0)
+               state->data[0] = 0x09;
+               state->data[1] = msg[0].len;
+               state->data[2] = msg[1].len;
+               state->data[3] = msg[0].addr;
+               memcpy(&state->data[4], msg[0].buf, msg[0].len);
+
+               if (dvb_usb_generic_rw(d, state->data, msg[0].len + 4,
+                                       state->data, msg[1].len + 1, 0) < 0)
                        err("i2c transfer failed.");
 
-               memcpy(msg[1].buf, &ibuf[1], msg[1].len);
+               memcpy(msg[1].buf, &state->data[1], msg[1].len);
                break;
        default:
                warn("more than 2 i2c messages at a time is not handled yet.");
                break;
        }
+       mutex_unlock(&d->data_mutex);
        mutex_unlock(&d->i2c_mutex);
        return num;
 }
@@ -845,17 +856,23 @@ static int su3000_streaming_ctrl(struct dvb_usb_adapter *adap, int onoff)
 static int su3000_power_ctrl(struct dvb_usb_device *d, int i)
 {
        struct dw2102_state *state = (struct dw2102_state *)d->priv;
-       u8 obuf[] = {0xde, 0};
+       int ret = 0;
 
        info("%s: %d, initialized %d", __func__, i, state->initialized);
 
        if (i && !state->initialized) {
+               mutex_lock(&d->data_mutex);
+
+               state->data[0] = 0xde;
+               state->data[1] = 0;
+
                state->initialized = 1;
                /* reset board */
-               return dvb_usb_generic_rw(d, obuf, 2, NULL, 0, 0);
+               ret = dvb_usb_generic_rw(d, state->data, 2, NULL, 0, 0);
+               mutex_unlock(&d->data_mutex);
        }
 
-       return 0;
+       return ret;
 }
 
 static int su3000_read_mac_address(struct dvb_usb_device *d, u8 mac[6])
@@ -1310,49 +1327,57 @@ static int prof_7500_frontend_attach(struct dvb_usb_adapter *d)
        return 0;
 }
 
-static int su3000_frontend_attach(struct dvb_usb_adapter *d)
+static int su3000_frontend_attach(struct dvb_usb_adapter *adap)
 {
-       u8 obuf[3] = { 0xe, 0x80, 0 };
-       u8 ibuf[] = { 0 };
+       struct dvb_usb_device *d = adap->dev;
+       struct dw2102_state *state = d->priv;
+
+       mutex_lock(&d->data_mutex);
+
+       state->data[0] = 0xe;
+       state->data[1] = 0x80;
+       state->data[2] = 0;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x02;
-       obuf[2] = 1;
+       state->data[0] = 0xe;
+       state->data[1] = 0x02;
+       state->data[2] = 1;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
        msleep(300);
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x83;
-       obuf[2] = 0;
+       state->data[0] = 0xe;
+       state->data[1] = 0x83;
+       state->data[2] = 0;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x83;
-       obuf[2] = 1;
+       state->data[0] = 0xe;
+       state->data[1] = 0x83;
+       state->data[2] = 1;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0x51;
+       state->data[0] = 0x51;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 1, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 1, state->data, 1, 0) < 0)
                err("command 0x51 transfer failed.");
 
-       d->fe_adap[0].fe = dvb_attach(ds3000_attach, &su3000_ds3000_config,
-                                       &d->dev->i2c_adap);
-       if (d->fe_adap[0].fe == NULL)
+       mutex_unlock(&d->data_mutex);
+
+       adap->fe_adap[0].fe = dvb_attach(ds3000_attach, &su3000_ds3000_config,
+                                       &d->i2c_adap);
+       if (adap->fe_adap[0].fe == NULL)
                return -EIO;
 
-       if (dvb_attach(ts2020_attach, d->fe_adap[0].fe,
+       if (dvb_attach(ts2020_attach, adap->fe_adap[0].fe,
                                &dw2104_ts2020_config,
-                               &d->dev->i2c_adap)) {
+                               &d->i2c_adap)) {
                info("Attached DS3000/TS2020!");
                return 0;
        }
@@ -1361,47 +1386,55 @@ static int su3000_frontend_attach(struct dvb_usb_adapter *d)
        return -EIO;
 }
 
-static int t220_frontend_attach(struct dvb_usb_adapter *d)
+static int t220_frontend_attach(struct dvb_usb_adapter *adap)
 {
-       u8 obuf[3] = { 0xe, 0x87, 0 };
-       u8 ibuf[] = { 0 };
+       struct dvb_usb_device *d = adap->dev;
+       struct dw2102_state *state = d->priv;
+
+       mutex_lock(&d->data_mutex);
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 3, ibuf, 1, 0) < 0)
+       state->data[0] = 0xe;
+       state->data[1] = 0x87;
+       state->data[2] = 0x0;
+
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x86;
-       obuf[2] = 1;
+       state->data[0] = 0xe;
+       state->data[1] = 0x86;
+       state->data[2] = 1;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x80;
-       obuf[2] = 0;
+       state->data[0] = 0xe;
+       state->data[1] = 0x80;
+       state->data[2] = 0;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
        msleep(50);
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x80;
-       obuf[2] = 1;
+       state->data[0] = 0xe;
+       state->data[1] = 0x80;
+       state->data[2] = 1;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0x51;
+       state->data[0] = 0x51;
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 1, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 1, state->data, 1, 0) < 0)
                err("command 0x51 transfer failed.");
 
-       d->fe_adap[0].fe = dvb_attach(cxd2820r_attach, &cxd2820r_config,
-                                       &d->dev->i2c_adap, NULL);
-       if (d->fe_adap[0].fe != NULL) {
-               if (dvb_attach(tda18271_attach, d->fe_adap[0].fe, 0x60,
-                                       &d->dev->i2c_adap, &tda18271_config)) {
+       mutex_unlock(&d->data_mutex);
+
+       adap->fe_adap[0].fe = dvb_attach(cxd2820r_attach, &cxd2820r_config,
+                                       &d->i2c_adap, NULL);
+       if (adap->fe_adap[0].fe != NULL) {
+               if (dvb_attach(tda18271_attach, adap->fe_adap[0].fe, 0x60,
+                                       &d->i2c_adap, &tda18271_config)) {
                        info("Attached TDA18271HD/CXD2820R!");
                        return 0;
                }
@@ -1411,23 +1444,30 @@ static int t220_frontend_attach(struct dvb_usb_adapter *d)
        return -EIO;
 }
 
-static int m88rs2000_frontend_attach(struct dvb_usb_adapter *d)
+static int m88rs2000_frontend_attach(struct dvb_usb_adapter *adap)
 {
-       u8 obuf[] = { 0x51 };
-       u8 ibuf[] = { 0 };
+       struct dvb_usb_device *d = adap->dev;
+       struct dw2102_state *state = d->priv;
+
+       mutex_lock(&d->data_mutex);
 
-       if (dvb_usb_generic_rw(d->dev, obuf, 1, ibuf, 1, 0) < 0)
+       state->data[0] = 0x51;
+
+       if (dvb_usb_generic_rw(d, state->data, 1, state->data, 1, 0) < 0)
                err("command 0x51 transfer failed.");
 
-       d->fe_adap[0].fe = dvb_attach(m88rs2000_attach, &s421_m88rs2000_config,
-                                       &d->dev->i2c_adap);
+       mutex_unlock(&d->data_mutex);
 
-       if (d->fe_adap[0].fe == NULL)
+       adap->fe_adap[0].fe = dvb_attach(m88rs2000_attach,
+                                       &s421_m88rs2000_config,
+                                       &d->i2c_adap);
+
+       if (adap->fe_adap[0].fe == NULL)
                return -EIO;
 
-       if (dvb_attach(ts2020_attach, d->fe_adap[0].fe,
+       if (dvb_attach(ts2020_attach, adap->fe_adap[0].fe,
                                &dw2104_ts2020_config,
-                               &d->dev->i2c_adap)) {
+                               &d->i2c_adap)) {
                info("Attached RS2000/TS2020!");
                return 0;
        }
@@ -1440,44 +1480,50 @@ static int tt_s2_4600_frontend_attach(struct dvb_usb_adapter *adap)
 {
        struct dvb_usb_device *d = adap->dev;
        struct dw2102_state *state = d->priv;
-       u8 obuf[3] = { 0xe, 0x80, 0 };
-       u8 ibuf[] = { 0 };
        struct i2c_adapter *i2c_adapter;
        struct i2c_client *client;
        struct i2c_board_info board_info;
        struct m88ds3103_platform_data m88ds3103_pdata = {};
        struct ts2020_config ts2020_config = {};
 
-       if (dvb_usb_generic_rw(d, obuf, 3, ibuf, 1, 0) < 0)
+       mutex_lock(&d->data_mutex);
+
+       state->data[0] = 0xe;
+       state->data[1] = 0x80;
+       state->data[2] = 0x0;
+
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x02;
-       obuf[2] = 1;
+       state->data[0] = 0xe;
+       state->data[1] = 0x02;
+       state->data[2] = 1;
 
-       if (dvb_usb_generic_rw(d, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
        msleep(300);
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x83;
-       obuf[2] = 0;
+       state->data[0] = 0xe;
+       state->data[1] = 0x83;
+       state->data[2] = 0;
 
-       if (dvb_usb_generic_rw(d, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0xe;
-       obuf[1] = 0x83;
-       obuf[2] = 1;
+       state->data[0] = 0xe;
+       state->data[1] = 0x83;
+       state->data[2] = 1;
 
-       if (dvb_usb_generic_rw(d, obuf, 3, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 3, state->data, 1, 0) < 0)
                err("command 0x0e transfer failed.");
 
-       obuf[0] = 0x51;
+       state->data[0] = 0x51;
 
-       if (dvb_usb_generic_rw(d, obuf, 1, ibuf, 1, 0) < 0)
+       if (dvb_usb_generic_rw(d, state->data, 1, state->data, 1, 0) < 0)
                err("command 0x51 transfer failed.");
 
+       mutex_unlock(&d->data_mutex);
+
        /* attach demod */
        m88ds3103_pdata.clk = 27000000;
        m88ds3103_pdata.i2c_wr_max = 33;