[PATCH v2 09/31] dibusb: don't do DMA on stack

From: Mauro Carvalho Chehab
Date: Tue Oct 11 2016 - 06:16:25 EST


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.boettcher@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
---
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