V4L/DVB (8773): cx18: Fix cx18_find_handle() and add error checking

cx18: Fix cx18_find_handle() and add error checking.  cx18_find_handle() did
not find a good task handle and would use the invalid task handle under common
conditions.  Added a define for the invalid task handle and added error checking
as well.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/cx18/cx18-driver.h

@@ -236,6 +236,8 @@ struct cx18_dvb {
 struct cx18;	 /* forward reference */
 struct cx18_scb; /* forward reference */
 
+#define CX18_INVALID_TASK_HANDLE 0xffffffff
+
 struct cx18_stream {
 	/* These first four fields are always set, even if the stream
 	   is not actually created. */

drivers/media/video/cx18/cx18-fileops.c

@@ -132,6 +132,7 @@ static void cx18_dualwatch(struct cx18 *cx)
 	u16 new_stereo_mode;
 	const u16 stereo_mask = 0x0300;
 	const u16 dual = 0x0200;
+	u32 h;
 
 	new_stereo_mode = cx->params.audio_properties & stereo_mask;
 	memset(&vt, 0, sizeof(vt));
@@ -143,13 +144,21 @@ static void cx18_dualwatch(struct cx18 *cx)
 	if (new_stereo_mode == cx->dualwatch_stereo_mode)
 		return;
 
-	new_bitmap = new_stereo_mode | (cx->params.audio_properties & ~stereo_mask);
+	new_bitmap = new_stereo_mode
+			| (cx->params.audio_properties & ~stereo_mask);
 
-	CX18_DEBUG_INFO("dualwatch: change stereo flag from 0x%x to 0x%x. new audio_bitmask=0x%ux\n",
-			   cx->dualwatch_stereo_mode, new_stereo_mode, new_bitmap);
+	CX18_DEBUG_INFO("dualwatch: change stereo flag from 0x%x to 0x%x. "
+			"new audio_bitmask=0x%ux\n",
+			cx->dualwatch_stereo_mode, new_stereo_mode, new_bitmap);
 
-	if (cx18_vapi(cx, CX18_CPU_SET_AUDIO_PARAMETERS, 2,
-				cx18_find_handle(cx), new_bitmap) == 0) {
+	h = cx18_find_handle(cx);
+	if (h == CX18_INVALID_TASK_HANDLE) {
+		CX18_DEBUG_INFO("dualwatch: can't find valid task handle\n");
+		return;
+	}
+
+	if (cx18_vapi(cx,
+		      CX18_CPU_SET_AUDIO_PARAMETERS, 2, h, new_bitmap) == 0) {
 		cx->dualwatch_stereo_mode = new_stereo_mode;
 		return;
 	}
@@ -695,20 +704,28 @@ int cx18_v4l2_open(struct inode *inode, struct file *filp)
 
 void cx18_mute(struct cx18 *cx)
 {
-	if (atomic_read(&cx->ana_capturing))
-		cx18_vapi(cx, CX18_CPU_SET_AUDIO_MUTE, 2,
-				cx18_find_handle(cx), 1);
+	u32 h;
+	if (atomic_read(&cx->ana_capturing)) {
+		h = cx18_find_handle(cx);
+		if (h != CX18_INVALID_TASK_HANDLE)
+			cx18_vapi(cx, CX18_CPU_SET_AUDIO_MUTE, 2, h, 1);
+		else
+			CX18_ERR("Can't find valid task handle for mute\n");
+	}
 	CX18_DEBUG_INFO("Mute\n");
 }
 
 void cx18_unmute(struct cx18 *cx)
 {
+	u32 h;
 	if (atomic_read(&cx->ana_capturing)) {
-		cx18_msleep_timeout(100, 0);
-		cx18_vapi(cx, CX18_CPU_SET_MISC_PARAMETERS, 2,
-				cx18_find_handle(cx), 12);
-		cx18_vapi(cx, CX18_CPU_SET_AUDIO_MUTE, 2,
-				cx18_find_handle(cx), 0);
+		h = cx18_find_handle(cx);
+		if (h != CX18_INVALID_TASK_HANDLE) {
+			cx18_msleep_timeout(100, 0);
+			cx18_vapi(cx, CX18_CPU_SET_MISC_PARAMETERS, 2, h, 12);
+			cx18_vapi(cx, CX18_CPU_SET_AUDIO_MUTE, 2, h, 0);
+		} else
+			CX18_ERR("Can't find valid task handle for unmute\n");
 	}
 	CX18_DEBUG_INFO("Unmute\n");
 }

drivers/media/video/cx18/cx18-ioctl.c

@@ -622,6 +622,7 @@ static int cx18_encoder_cmd(struct file *file, void *fh,
 {
 	struct cx18_open_id *id = fh;
 	struct cx18 *cx = id->cx;
+	u32 h;
 
 	switch (enc->cmd) {
 	case V4L2_ENC_CMD_START:
@@ -643,8 +644,14 @@ static int cx18_encoder_cmd(struct file *file, void *fh,
 			return -EPERM;
 		if (test_and_set_bit(CX18_F_I_ENC_PAUSED, &cx->i_flags))
 			return 0;
+		h = cx18_find_handle(cx);
+		if (h == CX18_INVALID_TASK_HANDLE) {
+			CX18_ERR("Can't find valid task handle for "
+				 "V4L2_ENC_CMD_PAUSE\n");
+			return -EBADFD;
+		}
 		cx18_mute(cx);
-		cx18_vapi(cx, CX18_CPU_CAPTURE_PAUSE, 1, cx18_find_handle(cx));
+		cx18_vapi(cx, CX18_CPU_CAPTURE_PAUSE, 1, h);
 		break;
 
 	case V4L2_ENC_CMD_RESUME:
@@ -654,7 +661,13 @@ static int cx18_encoder_cmd(struct file *file, void *fh,
 			return -EPERM;
 		if (!test_and_clear_bit(CX18_F_I_ENC_PAUSED, &cx->i_flags))
 			return 0;
-		cx18_vapi(cx, CX18_CPU_CAPTURE_RESUME, 1, cx18_find_handle(cx));
+		h = cx18_find_handle(cx);
+		if (h == CX18_INVALID_TASK_HANDLE) {
+			CX18_ERR("Can't find valid task handle for "
+				 "V4L2_ENC_CMD_RESUME\n");
+			return -EBADFD;
+		}
+		cx18_vapi(cx, CX18_CPU_CAPTURE_RESUME, 1, h);
 		cx18_unmute(cx);
 		break;
 

drivers/media/video/cx18/cx18-streams.c

@@ -119,7 +119,7 @@ static void cx18_stream_init(struct cx18 *cx, int type)
 	s->cx = cx;
 	s->type = type;
 	s->name = cx18_stream_info[type].name;
-	s->handle = 0xffffffff;
+	s->handle = CX18_INVALID_TASK_HANDLE;
 
 	s->dma = cx18_stream_info[type].dma;
 	s->buf_size = cx->stream_buf_size[type];
@@ -548,7 +548,7 @@ int cx18_stop_v4l2_encode_stream(struct cx18_stream *s, int gop_end)
 	clear_bit(CX18_F_S_STREAMING, &s->s_flags);
 
 	cx18_vapi(cx, CX18_DESTROY_TASK, 1, s->handle);
-	s->handle = 0xffffffff;
+	s->handle = CX18_INVALID_TASK_HANDLE;
 
 	if (atomic_read(&cx->tot_capturing) > 0)
 		return 0;
@@ -567,8 +567,8 @@ u32 cx18_find_handle(struct cx18 *cx)
 	for (i = 0; i < CX18_MAX_STREAMS; i++) {
 		struct cx18_stream *s = &cx->streams[i];
 
-		if (s->v4l2dev && s->handle)
+		if (s->v4l2dev && (s->handle != CX18_INVALID_TASK_HANDLE))
 			return s->handle;
 	}
-	return 0;
+	return CX18_INVALID_TASK_HANDLE;
 }