V4L/DVB (8829): gspca: Have a clean kmalloc-ated buffer for USB exchanges.

The USB buffer may be used for DMA and there may be a caching problem
if the buffer is part of the device structure.
Thanks to Alan Stern.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 78 insertions, 69 deletions

diff --git a/drivers/media/video/gspca/sunplus.c b/drivers/media/video/gspca/sunplus.c
index bddf73360c25..1cfcc6c49558 100644
--- a/drivers/media/video/gspca/sunplus.c
+++ b/drivers/media/video/gspca/sunplus.c
@@ -449,31 +449,47 @@ static const __u8 qtable_spca504_default[2][64] = {
 	 0x1e, 0x1e, 0x1e, 0x1e, 0x1e, 0x1e, 0x1e, 0x1e}
 };
 
-static void reg_r(struct usb_device *dev,
-			   __u16 req,
-			   __u16 index,
-			   __u8 *buffer, __u16 length)
+/* read <len> bytes to gspca_dev->usb_buf */
+static void reg_r(struct gspca_dev *gspca_dev,
+		  __u16 req,
+		  __u16 index,
+		  __u16 len)
 {
-	usb_control_msg(dev,
-			usb_rcvctrlpipe(dev, 0),
+#ifdef GSPCA_DEBUG
+	if (len > USB_BUF_SZ) {
+		err("reg_r: buffer overflow");
+		return;
+	}
+#endif
+	usb_control_msg(gspca_dev->dev,
+			usb_rcvctrlpipe(gspca_dev->dev, 0),
 			req,
 			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 			0,		/* value */
-			index, buffer, length,
+			index,
+			len ? gspca_dev->usb_buf : NULL, len,
 			500);
 }
 
-static void reg_w(struct usb_device *dev,
-			    __u16 req,
-			    __u16 value,
-			    __u16 index,
-			    __u8 *buffer, __u16 length)
+/* write <len> bytes from gspca_dev->usb_buf */
+static void reg_w(struct gspca_dev *gspca_dev,
+		   __u16 req,
+		   __u16 value,
+		   __u16 index,
+		   __u16 len)
 {
-	usb_control_msg(dev,
-			usb_sndctrlpipe(dev, 0),
+#ifdef GSPCA_DEBUG
+	if (len > USB_BUF_SZ) {
+		err("reg_w: buffer overflow");
+		return;
+	}
+#endif
+	usb_control_msg(gspca_dev->dev,
+			usb_sndctrlpipe(gspca_dev->dev, 0),
 			req,
 			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
-			value, index, buffer, length,
+			value, index,
+			len ? gspca_dev->usb_buf : NULL, len,
 			500);
 }
 
@@ -634,7 +650,7 @@ static int spca504B_PollingDataReady(struct gspca_dev *gspca_dev)
 	int count = 10;
 
 	while (--count > 0) {
-		reg_r(gspca_dev->dev, 0x21, 0, gspca_dev->usb_buf, 1);
+		reg_r(gspca_dev, 0x21, 0, 1);
 		if ((gspca_dev->usb_buf[0] & 0x01) == 0)
 			break;
 		msleep(10);
@@ -644,15 +660,14 @@ static int spca504B_PollingDataReady(struct gspca_dev *gspca_dev)
 
 static void spca504B_WaitCmdStatus(struct gspca_dev *gspca_dev)
 {
-	struct usb_device *dev = gspca_dev->dev;
 	int count = 50;
 
 	while (--count > 0) {
-		reg_r(dev, 0x21, 1, gspca_dev->usb_buf, 1);
+		reg_r(gspca_dev, 0x21, 1, 1);
 		if (gspca_dev->usb_buf[0] != 0) {
 			gspca_dev->usb_buf[0] = 0;
-			reg_w(dev, 0x21, 0, 1, gspca_dev->usb_buf, 1);
-			reg_r(dev, 0x21, 1, gspca_dev->usb_buf, 1);
+			reg_w(gspca_dev, 0x21, 0, 1, 1);
+			reg_r(gspca_dev, 0x21, 1, 1);
 			spca504B_PollingDataReady(gspca_dev);
 			break;
 		}
@@ -662,16 +677,14 @@ static void spca504B_WaitCmdStatus(struct gspca_dev *gspca_dev)
 
 static void spca50x_GetFirmware(struct gspca_dev *gspca_dev)
 {
-	struct usb_device *dev = gspca_dev->dev;
 	__u8 *data;
 
-	data = kmalloc(64, GFP_KERNEL);
-	reg_r(dev, 0x20, 0, data, 5);
+	data = gspca_dev->usb_buf;
+	reg_r(gspca_dev, 0x20, 0, 5);
 	PDEBUG(D_STREAM, "FirmWare : %d %d %d %d %d ",
 		data[0], data[1], data[2], data[3], data[4]);
-	reg_r(dev, 0x23, 0, data, 64);
-	reg_r(dev, 0x23, 1, data, 64);
-	kfree(data);
+	reg_r(gspca_dev, 0x23, 0, 64);
+	reg_r(gspca_dev, 0x23, 1, 64);
 }
 
 static void spca504B_SetSizeType(struct gspca_dev *gspca_dev)
@@ -686,21 +699,21 @@ static void spca504B_SetSizeType(struct gspca_dev *gspca_dev)
 	Type = 0;
 	switch (sd->bridge) {
 	case BRIDGE_SPCA533:
-		reg_w(dev, 0x31, 0, 0, NULL, 0);
+		reg_w(gspca_dev, 0x31, 0, 0, 0);
 		spca504B_WaitCmdStatus(gspca_dev);
 		rc = spca504B_PollingDataReady(gspca_dev);
 		spca50x_GetFirmware(gspca_dev);
 		gspca_dev->usb_buf[0] = 2;			/* type */
-		reg_w(dev, 0x24, 0, 8, gspca_dev->usb_buf, 1);
-		reg_r(dev, 0x24, 8, gspca_dev->usb_buf, 1);
+		reg_w(gspca_dev, 0x24, 0, 8, 1);
+		reg_r(gspca_dev, 0x24, 8, 1);
 
 		gspca_dev->usb_buf[0] = Size;
-		reg_w(dev, 0x25, 0, 4, gspca_dev->usb_buf, 1);
-		reg_r(dev, 0x25, 4, gspca_dev->usb_buf, 1);	/* size */
+		reg_w(gspca_dev, 0x25, 0, 4, 1);
+		reg_r(gspca_dev, 0x25, 4, 1);			/* size */
 		rc = spca504B_PollingDataReady(gspca_dev);
 
 		/* Init the cam width height with some values get on init ? */
-		reg_w(dev, 0x31, 0, 4, NULL, 0);
+		reg_w(gspca_dev, 0x31, 0, 4, 0);
 		spca504B_WaitCmdStatus(gspca_dev);
 		rc = spca504B_PollingDataReady(gspca_dev);
 		break;
@@ -708,12 +721,12 @@ static void spca504B_SetSizeType(struct gspca_dev *gspca_dev)
 /* case BRIDGE_SPCA504B: */
 /* case BRIDGE_SPCA536: */
 		gspca_dev->usb_buf[0] = Size;
-		reg_w(dev, 0x25, 0, 4, gspca_dev->usb_buf, 1);
-		reg_r(dev, 0x25, 4, gspca_dev->usb_buf, 1);	/* size */
+		reg_w(gspca_dev, 0x25, 0, 4, 1);
+		reg_r(gspca_dev, 0x25, 4, 1);			/* size */
 		Type = 6;
 		gspca_dev->usb_buf[0] = Type;
-		reg_w(dev, 0x27, 0, 0, gspca_dev->usb_buf, 1);
-		reg_r(dev, 0x27, 0, gspca_dev->usb_buf, 1);	/* type */
+		reg_w(gspca_dev, 0x27, 0, 0, 1);
+		reg_r(gspca_dev, 0x27, 0, 1);			/* type */
 		rc = spca504B_PollingDataReady(gspca_dev);
 		break;
 	case BRIDGE_SPCA504:
@@ -752,18 +765,15 @@ static void spca504_wait_status(struct gspca_dev *gspca_dev)
 
 static void spca504B_setQtable(struct gspca_dev *gspca_dev)
 {
-	struct usb_device *dev = gspca_dev->dev;
-
 	gspca_dev->usb_buf[0] = 3;
-	reg_w(dev, 0x26, 0, 0, gspca_dev->usb_buf, 1);
-	reg_r(dev, 0x26, 0, gspca_dev->usb_buf, 1);
+	reg_w(gspca_dev, 0x26, 0, 0, 1);
+	reg_r(gspca_dev, 0x26, 0, 1);
 	spca504B_PollingDataReady(gspca_dev);
 }
 
 static void sp5xx_initContBrigHueRegisters(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
-	struct usb_device *dev = gspca_dev->dev;
 	int pollreg = 1;
 
 	switch (sd->bridge) {
@@ -774,20 +784,20 @@ static void sp5xx_initContBrigHueRegisters(struct gspca_dev *gspca_dev)
 	default:
 /*	case BRIDGE_SPCA533: */
 /*	case BRIDGE_SPCA504B: */
-		reg_w(dev, 0, 0, 0x21a7, NULL, 0);	/* brightness */
-		reg_w(dev, 0, 0x20, 0x21a8, NULL, 0);	/* contrast */
-		reg_w(dev, 0, 0, 0x21ad, NULL, 0);	/* hue */
-		reg_w(dev, 0, 1, 0x21ac, NULL, 0);	/* sat/hue */
-		reg_w(dev, 0, 0x20, 0x21ae, NULL, 0);	/* saturation */
-		reg_w(dev, 0, 0, 0x21a3, NULL, 0);	/* gamma */
+		reg_w(gspca_dev, 0, 0, 0x21a7, 0);	/* brightness */
+		reg_w(gspca_dev, 0, 0x20, 0x21a8, 0);	/* contrast */
+		reg_w(gspca_dev, 0, 0, 0x21ad, 0);	/* hue */
+		reg_w(gspca_dev, 0, 1, 0x21ac, 0);	/* sat/hue */
+		reg_w(gspca_dev, 0, 0x20, 0x21ae, 0);	/* saturation */
+		reg_w(gspca_dev, 0, 0, 0x21a3, 0);	/* gamma */
 		break;
 	case BRIDGE_SPCA536:
-		reg_w(dev, 0, 0, 0x20f0, NULL, 0);
-		reg_w(dev, 0, 0x21, 0x20f1, NULL, 0);
-		reg_w(dev, 0, 0x40, 0x20f5, NULL, 0);
-		reg_w(dev, 0, 1, 0x20f4, NULL, 0);
-		reg_w(dev, 0, 0x40, 0x20f6, NULL, 0);
-		reg_w(dev, 0, 0, 0x2089, NULL, 0);
+		reg_w(gspca_dev, 0, 0, 0x20f0, 0);
+		reg_w(gspca_dev, 0, 0x21, 0x20f1, 0);
+		reg_w(gspca_dev, 0, 0x40, 0x20f5, 0);
+		reg_w(gspca_dev, 0, 1, 0x20f4, 0);
+		reg_w(gspca_dev, 0, 0x40, 0x20f6, 0);
+		reg_w(gspca_dev, 0, 0, 0x2089, 0);
 		break;
 	}
 	if (pollreg)
@@ -799,7 +809,6 @@ static int sd_config(struct gspca_dev *gspca_dev,
 			const struct usb_device_id *id)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
-	struct usb_device *dev = gspca_dev->dev;
 	struct cam *cam;
 
 	cam = &gspca_dev->cam;
@@ -811,7 +820,7 @@ static int sd_config(struct gspca_dev *gspca_dev,
 	if (sd->subtype == AiptekMiniPenCam13) {
 /* try to get the firmware as some cam answer 2.0.1.2.2
  * and should be a spca504b then overwrite that setting */
-		reg_r(dev, 0x20, 0, gspca_dev->usb_buf, 1);
+		reg_r(gspca_dev, 0x20, 0, 1);
 		switch (gspca_dev->usb_buf[0]) {
 		case 1:
 			break;		/* (right bridge/subtype) */
@@ -860,12 +869,12 @@ static int sd_init(struct gspca_dev *gspca_dev)
 
 	switch (sd->bridge) {
 	case BRIDGE_SPCA504B:
-		reg_w(dev, 0x1d, 0, 0, NULL, 0);
-		reg_w(dev, 0, 1, 0x2306, NULL, 0);
-		reg_w(dev, 0, 0, 0x0d04, NULL, 0);
-		reg_w(dev, 0, 0, 0x2000, NULL, 0);
-		reg_w(dev, 0, 0x13, 0x2301, NULL, 0);
-		reg_w(dev, 0, 0, 0x2306, NULL, 0);
+		reg_w(gspca_dev, 0x1d, 0, 0, 0);
+		reg_w(gspca_dev, 0, 1, 0x2306, 0);
+		reg_w(gspca_dev, 0, 0, 0x0d04, 0);
+		reg_w(gspca_dev, 0, 0, 0x2000, 0);
+		reg_w(gspca_dev, 0, 0x13, 0x2301, 0);
+		reg_w(gspca_dev, 0, 0, 0x2306, 0);
 		/* fall thru */
 	case BRIDGE_SPCA533:
 		rc = spca504B_PollingDataReady(gspca_dev);
@@ -873,12 +882,12 @@ static int sd_init(struct gspca_dev *gspca_dev)
 		break;
 	case BRIDGE_SPCA536:
 		spca50x_GetFirmware(gspca_dev);
-		reg_r(dev, 0x00, 0x5002, gspca_dev->usb_buf, 1);
+		reg_r(gspca_dev, 0x00, 0x5002, 1);
 		gspca_dev->usb_buf[0] = 0;
-		reg_w(dev, 0x24, 0, 0, gspca_dev->usb_buf, 1);
-		reg_r(dev, 0x24, 0, gspca_dev->usb_buf, 1);
+		reg_w(gspca_dev, 0x24, 0, 0, 1);
+		reg_r(gspca_dev, 0x24, 0, 1);
 		rc = spca504B_PollingDataReady(gspca_dev);
-		reg_w(dev, 0x34, 0, 0, NULL, 0);
+		reg_w(gspca_dev, 0x34, 0, 0, 0);
 		spca504B_WaitCmdStatus(gspca_dev);
 		break;
 	case BRIDGE_SPCA504C:	/* pccam600 */
@@ -971,12 +980,12 @@ static void sd_start(struct gspca_dev *gspca_dev)
 /*	case BRIDGE_SPCA536: */
 		if (sd->subtype == MegapixV4 ||
 		    sd->subtype == LogitechClickSmart820) {
-			reg_w(dev, 0xf0, 0, 0, NULL, 0);
+			reg_w(gspca_dev, 0xf0, 0, 0, 0);
 			spca504B_WaitCmdStatus(gspca_dev);
-			reg_r(dev, 0xf0, 4, NULL, 0);
+			reg_r(gspca_dev, 0xf0, 4, 0);
 			spca504B_WaitCmdStatus(gspca_dev);
 		} else {
-			reg_w(dev, 0x31, 0, 4, NULL, 0);
+			reg_w(gspca_dev, 0x31, 0, 4, 0);
 			spca504B_WaitCmdStatus(gspca_dev);
 			rc = spca504B_PollingDataReady(gspca_dev);
 		}
@@ -1045,7 +1054,7 @@ static void sd_stopN(struct gspca_dev *gspca_dev)
 /*	case BRIDGE_SPCA533: */
 /*	case BRIDGE_SPCA536: */
 /*	case BRIDGE_SPCA504B: */
-		reg_w(dev, 0x31, 0, 0, NULL, 0);
+		reg_w(gspca_dev, 0x31, 0, 0, 0);
 		spca504B_WaitCmdStatus(gspca_dev);
 		spca504B_PollingDataReady(gspca_dev);
 		break;