V4L/DVB (12326): zr364xx: error message when buffer is too small and code cleanup

. added code to print an error message when buffer is too small to hold frame
data, that is better than just a hard crash. Tested using MAX_FRAME_SIZE =
50000, lots of error messages appeared in /var/log/messages but no crash.

. removed line "f->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;" in
zr364xx_vidioc_try_fmt_vid_cap, it should not be there.

. changes to improve performance (or at least not hurt it): removed some
unneeded debug messages; added macro FULL_DEBUG to enable debug messages in
performance critical places, this macro is disabled by default; removed "if
(frm->lpvbits == NULL)..." in zr364xx_read_video_callback because after
analisying the source code I concluded it will always results to false, so it
is not needed.

. some small code reorganization.

Signed-off-by: Lamarque V. Souza <lamarque@gmail.com>
Signed-off-by: Antoine Jacquet <royale@zerezo.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/zr364xx.c b/drivers/media/video/zr364xx.c
index 009f873..9aae011 100644 (file)
--- a/drivers/media/video/zr364xx.c
+++ b/drivers/media/video/zr364xx.c
@@ -66,6 +66,13 @@
                } \
        } while (0)
 
+/*#define FULL_DEBUG 1*/
+#ifdef FULL_DEBUG
+#define _DBG DBG
+#else
+#define _DBG(fmt, args...)
+#endif
+
 /* Init methods, need to find nicer names for these
  * the exact names of the chipsets would be the best if someone finds it */
 #define METHOD0 0
@@ -375,7 +382,7 @@ static int buffer_setup(struct videobuf_queue *vq, unsigned int *count,
 
 static void free_buffer(struct videobuf_queue *vq, struct zr364xx_buffer *buf)
 {
-       DBG("%s\n", __func__);
+       _DBG("%s\n", __func__);
 
        if (in_interrupt())
                BUG();
@@ -428,7 +435,7 @@ static void buffer_queue(struct videobuf_queue *vq, struct videobuf_buffer *vb)
                                                  vb);
        struct zr364xx_camera *cam = vq->priv_data;
 
-       DBG("%s\n", __func__);
+       _DBG("%s\n", __func__);
 
        buf->vb.state = VIDEOBUF_QUEUED;
        list_add_tail(&buf->vb.queue, &cam->vidq.active);
@@ -440,7 +447,7 @@ static void buffer_release(struct videobuf_queue *vq,
        struct zr364xx_buffer *buf = container_of(vb, struct zr364xx_buffer,
                                                  vb);
 
-       DBG("%s\n", __func__);
+       _DBG("%s\n", __func__);
        free_buffer(vq, buf);
 }
 
@@ -462,7 +469,7 @@ static ssize_t zr364xx_read(struct file *file, char __user *buf, size_t count,
 {
        struct zr364xx_camera *cam = video_drvdata(file);
 
-       DBG("%s\n", __func__);
+       _DBG("%s\n", __func__);
 
        if (!buf)
                return -EINVAL;
@@ -582,7 +589,7 @@ static int zr364xx_read_video_callback(struct zr364xx_camera *cam,
        int i = 0;
        unsigned char *ptr = NULL;
 
-       /*DBG("buffer to user\n");*/
+       _DBG("buffer to user\n");
        idx = cam->cur_frame;
        frm = &cam->buffer.frame[idx];
 
@@ -600,12 +607,6 @@ static int zr364xx_read_video_callback(struct zr364xx_camera *cam,
                return -EINVAL;
        }
 
-       if (frm->lpvbits == NULL) {
-               DBG("%s: frame buffer == NULL.%p %p %d\n", __func__,
-                       frm, cam, idx);
-               return -ENOMEM;
-       }
-
        psrc = (u8 *)pipe_info->transfer_buffer;
        ptr = pdest = frm->lpvbits;
 
@@ -613,7 +614,7 @@ static int zr364xx_read_video_callback(struct zr364xx_camera *cam,
                frm->ulState = ZR364XX_READ_FRAME;
                frm->cur_size = 0;
 
-               DBG("jpeg header, ");
+               _DBG("jpeg header, ");
                memcpy(ptr, header1, sizeof(header1));
                ptr += sizeof(header1);
                header3 = 0;
@@ -631,21 +632,28 @@ static int zr364xx_read_video_callback(struct zr364xx_camera *cam,
                memcpy(ptr, psrc + 128,
                       purb->actual_length - 128);
                ptr += purb->actual_length - 128;
-               DBG("header : %d %d %d %d %d %d %d %d %d\n",
+               _DBG("header : %d %d %d %d %d %d %d %d %d\n",
                    psrc[0], psrc[1], psrc[2],
                    psrc[3], psrc[4], psrc[5],
                    psrc[6], psrc[7], psrc[8]);
                frm->cur_size = ptr - pdest;
        } else {
-               pdest += frm->cur_size;
-               memcpy(pdest, psrc, purb->actual_length);
-               frm->cur_size += purb->actual_length;
+               if (frm->cur_size + purb->actual_length > MAX_FRAME_SIZE) {
+                       dev_info(&cam->udev->dev,
+                                "%s: buffer (%d bytes) too small to hold "
+                                "frame data. Discarding frame data.\n",
+                                __func__, MAX_FRAME_SIZE);
+               } else {
+                       pdest += frm->cur_size;
+                       memcpy(pdest, psrc, purb->actual_length);
+                       frm->cur_size += purb->actual_length;
+               }
        }
-       /*DBG("cur_size %lu urb size %d\n", frm->cur_size,
+       /*_DBG("cur_size %lu urb size %d\n", frm->cur_size,
                purb->actual_length);*/
 
        if (purb->actual_length < pipe_info->transfer_size) {
-               DBG("****************Buffer[%d]full*************\n", idx);
+               _DBG("****************Buffer[%d]full*************\n", idx);
                cam->last_frame = cam->cur_frame;
                cam->cur_frame++;
                /* end of system frame ring buffer, start at zero */
@@ -680,7 +688,7 @@ static int zr364xx_read_video_callback(struct zr364xx_camera *cam,
                        if (cam->skip)
                                cam->skip--;
                        else {
-                               DBG("jpeg(%lu): %d %d %d %d %d %d %d %d\n",
+                               _DBG("jpeg(%lu): %d %d %d %d %d %d %d %d\n",
                                    frm->cur_size,
                                    pdest[0], pdest[1], pdest[2], pdest[3],
                                    pdest[4], pdest[5], pdest[6], pdest[7]);
@@ -707,7 +715,7 @@ static int res_get(struct zr364xx_camera *cam)
        }
        /* it's free, grab it */
        cam->resources = 1;
-       DBG("res: get\n");
+       _DBG("res: get\n");
        mutex_unlock(&cam->lock);
        return 1;
 }
@@ -722,7 +730,7 @@ static void res_free(struct zr364xx_camera *cam)
        mutex_lock(&cam->lock);
        cam->resources = 0;
        mutex_unlock(&cam->lock);
-       DBG("res: put\n");
+       _DBG("res: put\n");
 }
 
 static int zr364xx_vidioc_querycap(struct file *file, void *priv,
@@ -881,7 +889,6 @@ static int zr364xx_vidioc_try_fmt_vid_cap(struct file *file, void *priv,
        }
 
        f->fmt.pix.field = V4L2_FIELD_NONE;
-       f->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        f->fmt.pix.bytesperline = f->fmt.pix.width * 2;
        f->fmt.pix.sizeimage = f->fmt.pix.height * f->fmt.pix.bytesperline;
        f->fmt.pix.colorspace = 0;
@@ -1017,7 +1024,7 @@ static int zr364xx_vidioc_qbuf(struct file *file,
 {
        int rc;
        struct zr364xx_camera *cam = video_drvdata(file);
-       DBG("%s\n", __func__);
+       _DBG("%s\n", __func__);
        rc = videobuf_qbuf(&cam->vb_vidq, p);
        return rc;
 }
@@ -1028,7 +1035,7 @@ static int zr364xx_vidioc_dqbuf(struct file *file,
 {
        int rc;
        struct zr364xx_camera *cam = video_drvdata(file);
-       DBG("%s\n", __func__);
+       _DBG("%s\n", __func__);
        rc = videobuf_dqbuf(&cam->vb_vidq, p, file->f_flags & O_NONBLOCK);
        return rc;
 }
@@ -1040,7 +1047,7 @@ static void read_pipe_completion(struct urb *purb)
        int pipe;
 
        pipe_info = purb->context;
-       /*DBG("%s %p, status %d\n", __func__, purb, purb->status);*/
+       _DBG("%s %p, status %d\n", __func__, purb, purb->status);
        if (pipe_info == NULL) {
                printk(KERN_ERR KBUILD_MODNAME ": no context!\n");
                return;
@@ -1151,7 +1158,6 @@ static void zr364xx_stop_readpipe(struct zr364xx_camera *cam)
                        pipe_info->stream_urb = NULL;
                }
        }
-       DBG("stop read pipe\n");
        return;
 }
 
@@ -1214,7 +1220,6 @@ static int zr364xx_vidioc_streamon(struct file *file, void *priv,
        } else {
                res_free(cam);
        }
-       DBG("%s: %d\n", __func__, res);
        return res;
 }
 
@@ -1326,8 +1331,6 @@ static void zr364xx_destroy(struct zr364xx_camera *cam)
        /* release transfer buffer */
        kfree(cam->pipe->transfer_buffer);
        cam->pipe->transfer_buffer = NULL;
-
-       DBG("%s\n", __func__);
        mutex_unlock(&cam->open_lock);
        kfree(cam);
        cam = NULL;
@@ -1408,7 +1411,7 @@ static unsigned int zr364xx_poll(struct file *file,
 {
        struct zr364xx_camera *cam = video_drvdata(file);
        struct videobuf_queue *q = &cam->vb_vidq;
-       DBG("%s\n", __func__);
+       _DBG("%s\n", __func__);
 
        if (cam->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return POLLERR;