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>

4 files changed, 51 insertions, 19 deletions

diff --git a/drivers/media/video/cx18/cx18-driver.h b/drivers/media/video/cx18/cx18-driver.h
index 8812a5ec635f..26359897d147 100644
--- a/drivers/media/video/cx18/cx18-driver.h
+++ b/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. */
diff --git a/drivers/media/video/cx18/cx18-fileops.c b/drivers/media/video/cx18/cx18-fileops.c
index eb0144f95562..5f9089907544 100644
--- a/drivers/media/video/cx18/cx18-fileops.c
+++ b/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");
 }
diff --git a/drivers/media/video/cx18/cx18-ioctl.c b/drivers/media/video/cx18/cx18-ioctl.c
index 5325c7aacaf3..84507a39f2b8 100644
--- a/drivers/media/video/cx18/cx18-ioctl.c
+++ b/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;
 
diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c
index 45dc6f399ed4..53c5852bba37 100644
--- a/drivers/media/video/cx18/cx18-streams.c
+++ b/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;
 }