media: dvb: i2c transfers over usb cannot be done from stack

Since commit 29d2fef8be11 ("usb: catch attempts to submit urbs
with a vmalloc'd transfer buffer"), the AverMedia AverTV DVB-T
USB 2.0 (a800) fails to probe.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 39 insertions, 11 deletions

diff --git a/drivers/media/dvb-frontends/dib3000mc.c b/drivers/media/dvb-frontends/dib3000mc.c
index 224283fe100a..4d086a7248e9 100644
--- a/drivers/media/dvb-frontends/dib3000mc.c
+++ b/drivers/media/dvb-frontends/dib3000mc.c
@@ -55,29 +55,57 @@ struct dib3000mc_state {
 
 static u16 dib3000mc_read_word(struct dib3000mc_state *state, u16 reg)
 {
-	u8 wb[2] = { (reg >> 8) | 0x80, reg & 0xff };
-	u8 rb[2];
 	struct i2c_msg msg[2] = {
-		{ .addr = state->i2c_addr >> 1, .flags = 0,        .buf = wb, .len = 2 },
-		{ .addr = state->i2c_addr >> 1, .flags = I2C_M_RD, .buf = rb, .len = 2 },
+		{ .addr = state->i2c_addr >> 1, .flags = 0,        .len = 2 },
+		{ .addr = state->i2c_addr >> 1, .flags = I2C_M_RD, .len = 2 },
 	};
+	u16 word;
+	u8 *b;
+
+	b = kmalloc(4, GFP_KERNEL);
+	if (!b)
+		return 0;
+
+	b[0] = (reg >> 8) | 0x80;
+	b[1] = reg;
+	b[2] = 0;
+	b[3] = 0;
+
+	msg[0].buf = b;
+	msg[1].buf = b + 2;
 
 	if (i2c_transfer(state->i2c_adap, msg, 2) != 2)
 		dprintk("i2c read error on %d\n",reg);
 
-	return (rb[0] << 8) | rb[1];
+	word = (b[2] << 8) | b[3];
+	kfree(b);
+
+	return word;
 }
 
 static int dib3000mc_write_word(struct dib3000mc_state *state, u16 reg, u16 val)
 {
-	u8 b[4] = {
-		(reg >> 8) & 0xff, reg & 0xff,
-		(val >> 8) & 0xff, val & 0xff,
-	};
 	struct i2c_msg msg = {
-		.addr = state->i2c_addr >> 1, .flags = 0, .buf = b, .len = 4
+		.addr = state->i2c_addr >> 1, .flags = 0, .len = 4
 	};
-	return i2c_transfer(state->i2c_adap, &msg, 1) != 1 ? -EREMOTEIO : 0;
+	int rc;
+	u8 *b;
+
+	b = kmalloc(4, GFP_KERNEL);
+	if (!b)
+		return -ENOMEM;
+
+	b[0] = reg >> 8;
+	b[1] = reg;
+	b[2] = val >> 8;
+	b[3] = val;
+
+	msg.buf = b;
+
+	rc = i2c_transfer(state->i2c_adap, &msg, 1) != 1 ? -EREMOTEIO : 0;
+	kfree(b);
+
+	return rc;
 }
 
 static int dib3000mc_identify(struct dib3000mc_state *state)