1 files changed, 72 insertions, 46 deletions

diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c
index 95a3f5e82ae..2e8f1df775b 100644
--- a/drivers/media/video/videobuf2-core.c
+++ b/drivers/media/video/videobuf2-core.c
@@ -30,7 +30,7 @@ module_param(debug, int, 0644);
 			printk(KERN_DEBUG "vb2: " fmt, ## arg);		\
 	} while (0)
 
-#define call_memop(q, plane, op, args...)				\
+#define call_memop(q, op, args...)					\
 	(((q)->mem_ops->op) ?						\
 		((q)->mem_ops->op(args)) : 0)
 
@@ -52,7 +52,7 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
 
 	/* Allocate memory for all planes in this buffer */
 	for (plane = 0; plane < vb->num_planes; ++plane) {
-		mem_priv = call_memop(q, plane, alloc, q->alloc_ctx[plane],
+		mem_priv = call_memop(q, alloc, q->alloc_ctx[plane],
 				      q->plane_sizes[plane]);
 		if (IS_ERR_OR_NULL(mem_priv))
 			goto free;
@@ -65,8 +65,10 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
 	return 0;
 free:
 	/* Free already allocated memory if one of the allocations failed */
-	for (; plane > 0; --plane)
-		call_memop(q, plane, put, vb->planes[plane - 1].mem_priv);
+	for (; plane > 0; --plane) {
+		call_memop(q, put, vb->planes[plane - 1].mem_priv);
+		vb->planes[plane - 1].mem_priv = NULL;
+	}
 
 	return -ENOMEM;
 }
@@ -80,10 +82,10 @@ static void __vb2_buf_mem_free(struct vb2_buffer *vb)
 	unsigned int plane;
 
 	for (plane = 0; plane < vb->num_planes; ++plane) {
-		call_memop(q, plane, put, vb->planes[plane].mem_priv);
+		call_memop(q, put, vb->planes[plane].mem_priv);
 		vb->planes[plane].mem_priv = NULL;
-		dprintk(3, "Freed plane %d of buffer %d\n",
-				plane, vb->v4l2_buf.index);
+		dprintk(3, "Freed plane %d of buffer %d\n", plane,
+			vb->v4l2_buf.index);
 	}
 }
 
@@ -97,12 +99,9 @@ static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
 	unsigned int plane;
 
 	for (plane = 0; plane < vb->num_planes; ++plane) {
-		void *mem_priv = vb->planes[plane].mem_priv;
-
-		if (mem_priv) {
-			call_memop(q, plane, put_userptr, mem_priv);
-			vb->planes[plane].mem_priv = NULL;
-		}
+		if (vb->planes[plane].mem_priv)
+			call_memop(q, put_userptr, vb->planes[plane].mem_priv);
+		vb->planes[plane].mem_priv = NULL;
 	}
 }
 
@@ -305,7 +304,7 @@ static bool __buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb)
 		 * case anyway. If num_users() returns more than 1,
 		 * we are not the only user of the plane's memory.
 		 */
-		if (mem_priv && call_memop(q, plane, num_users, mem_priv) > 1)
+		if (mem_priv && call_memop(q, num_users, mem_priv) > 1)
 			return true;
 	}
 	return false;
@@ -731,10 +730,10 @@ void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no)
 {
 	struct vb2_queue *q = vb->vb2_queue;
 
-	if (plane_no > vb->num_planes)
+	if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
 		return NULL;
 
-	return call_memop(q, plane_no, vaddr, vb->planes[plane_no].mem_priv);
+	return call_memop(q, vaddr, vb->planes[plane_no].mem_priv);
 
 }
 EXPORT_SYMBOL_GPL(vb2_plane_vaddr);
@@ -754,10 +753,10 @@ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no)
 {
 	struct vb2_queue *q = vb->vb2_queue;
 
-	if (plane_no > vb->num_planes)
+	if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
 		return NULL;
 
-	return call_memop(q, plane_no, cookie, vb->planes[plane_no].mem_priv);
+	return call_memop(q, cookie, vb->planes[plane_no].mem_priv);
 }
 EXPORT_SYMBOL_GPL(vb2_plane_cookie);
 
@@ -883,7 +882,8 @@ static int __qbuf_userptr(struct vb2_buffer *vb, const struct v4l2_buffer *b)
 
 	for (plane = 0; plane < vb->num_planes; ++plane) {
 		/* Skip the plane if already verified */
-		if (vb->v4l2_planes[plane].m.userptr == planes[plane].m.userptr
+		if (vb->v4l2_planes[plane].m.userptr &&
+		    vb->v4l2_planes[plane].m.userptr == planes[plane].m.userptr
 		    && vb->v4l2_planes[plane].length == planes[plane].length)
 			continue;
 
@@ -898,27 +898,23 @@ static int __qbuf_userptr(struct vb2_buffer *vb, const struct v4l2_buffer *b)
 
 		/* Release previously acquired memory if present */
 		if (vb->planes[plane].mem_priv)
-			call_memop(q, plane, put_userptr,
-					vb->planes[plane].mem_priv);
+			call_memop(q, put_userptr, vb->planes[plane].mem_priv);
 
 		vb->planes[plane].mem_priv = NULL;
 		vb->v4l2_planes[plane].m.userptr = 0;
 		vb->v4l2_planes[plane].length = 0;
 
 		/* Acquire each plane's memory */
-		if (q->mem_ops->get_userptr) {
-			mem_priv = q->mem_ops->get_userptr(q->alloc_ctx[plane],
-							planes[plane].m.userptr,
-							planes[plane].length,
-							write);
-			if (IS_ERR(mem_priv)) {
-				dprintk(1, "qbuf: failed acquiring userspace "
+		mem_priv = call_memop(q, get_userptr, q->alloc_ctx[plane],
+				      planes[plane].m.userptr,
+				      planes[plane].length, write);
+		if (IS_ERR_OR_NULL(mem_priv)) {
+			dprintk(1, "qbuf: failed acquiring userspace "
 						"memory for plane %d\n", plane);
-				ret = PTR_ERR(mem_priv);
-				goto err;
-			}
-			vb->planes[plane].mem_priv = mem_priv;
+			ret = mem_priv ? PTR_ERR(mem_priv) : -EINVAL;
+			goto err;
 		}
+		vb->planes[plane].mem_priv = mem_priv;
 	}
 
 	/*
@@ -943,8 +939,7 @@ err:
 	/* In case of errors, release planes that were already acquired */
 	for (plane = 0; plane < vb->num_planes; ++plane) {
 		if (vb->planes[plane].mem_priv)
-			call_memop(q, plane, put_userptr,
-				   vb->planes[plane].mem_priv);
+			call_memop(q, put_userptr, vb->planes[plane].mem_priv);
 		vb->planes[plane].mem_priv = NULL;
 		vb->v4l2_planes[plane].m.userptr = 0;
 		vb->v4l2_planes[plane].length = 0;
@@ -1081,46 +1076,76 @@ EXPORT_SYMBOL_GPL(vb2_prepare_buf);
  */
 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
 {
+	struct rw_semaphore *mmap_sem = NULL;
 	struct vb2_buffer *vb;
-	int ret;
+	int ret = 0;
+
+	/*
+	 * In case of user pointer buffers vb2 allocator needs to get direct
+	 * access to userspace pages. This requires getting read access on
+	 * mmap semaphore in the current process structure. The same
+	 * semaphore is taken before calling mmap operation, while both mmap
+	 * and qbuf are called by the driver or v4l2 core with driver's lock
+	 * held. To avoid a AB-BA deadlock (mmap_sem then driver's lock in
+	 * mmap and driver's lock then mmap_sem in qbuf) the videobuf2 core
+	 * release driver's lock, takes mmap_sem and then takes again driver's
+	 * lock.
+	 *
+	 * To avoid race with other vb2 calls, which might be called after
+	 * releasing driver's lock, this operation is performed at the
+	 * beggining of qbuf processing. This way the queue status is
+	 * consistent after getting driver's lock back.
+	 */
+	if (q->memory == V4L2_MEMORY_USERPTR) {
+		mmap_sem = &current->mm->mmap_sem;
+		call_qop(q, wait_prepare, q);
+		down_read(mmap_sem);
+		call_qop(q, wait_finish, q);
+	}
 
 	if (q->fileio) {
 		dprintk(1, "qbuf: file io in progress\n");
-		return -EBUSY;
+		ret = -EBUSY;
+		goto unlock;
 	}
 
 	if (b->type != q->type) {
 		dprintk(1, "qbuf: invalid buffer type\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto unlock;
 	}
 
 	if (b->index >= q->num_buffers) {
 		dprintk(1, "qbuf: buffer index out of range\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto unlock;
 	}
 
 	vb = q->bufs[b->index];
 	if (NULL == vb) {
 		/* Should never happen */
 		dprintk(1, "qbuf: buffer is NULL\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto unlock;
 	}
 
 	if (b->memory != q->memory) {
 		dprintk(1, "qbuf: invalid memory type\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto unlock;
 	}
 
 	switch (vb->state) {
 	case VB2_BUF_STATE_DEQUEUED:
 		ret = __buf_prepare(vb, b);
 		if (ret)
-			return ret;
+			goto unlock;
 	case VB2_BUF_STATE_PREPARED:
 		break;
 	default:
 		dprintk(1, "qbuf: buffer already in use\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto unlock;
 	}
 
 	/*
@@ -1141,7 +1166,10 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
 	__fill_v4l2_buffer(vb, b);
 
 	dprintk(1, "qbuf of buffer %d succeeded\n", vb->v4l2_buf.index);
-	return 0;
+unlock:
+	if (mmap_sem)
+		up_read(mmap_sem);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(vb2_qbuf);
 
@@ -1521,7 +1549,6 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
 {
 	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
-	struct vb2_plane *vb_plane;
 	struct vb2_buffer *vb;
 	unsigned int buffer, plane;
 	int ret;
@@ -1558,9 +1585,8 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
 		return ret;
 
 	vb = q->bufs[buffer];
-	vb_plane = &vb->planes[plane];
 
-	ret = q->mem_ops->mmap(vb_plane->mem_priv, vma);
+	ret = call_memop(q, mmap, vb->planes[plane].mem_priv, vma);
 	if (ret)
 		return ret;