[media] media: vb2: review mem_priv usage and fix potential bugs

This patch is a result of review of mem_priv entry usage in videobuf2 core.
It fixes all all potential places where it was not checked against NULL or
zeroed after freeing as well as a few style issues.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 19 insertions, 25 deletions

diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c
index 9dc887b2aac0..26cfbf5c9f8c 100644
--- a/drivers/media/video/videobuf2-core.c
+++ b/drivers/media/video/videobuf2-core.c
@@ -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)
+        for (; plane > 0; --plane) {
                 call_memop(q, put, vb->planes[plane - 1].mem_priv);
+                vb->planes[plane - 1].mem_priv = NULL;
+        }
 
         return -ENOMEM;
 }
@@ -82,8 +84,8 @@ static void __vb2_buf_mem_free(struct vb2_buffer *vb)
         for (plane = 0; plane < vb->num_planes; ++plane) {
                 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, 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;
         }
 }
 
@@ -731,7 +730,7 @@ 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, vaddr, vb->planes[plane_no].mem_priv);
@@ -754,7 +753,7 @@ 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, cookie, vb->planes[plane_no].mem_priv);
@@ -906,19 +905,16 @@ static int __qbuf_userptr(struct vb2_buffer *vb, const struct v4l2_buffer *b)
                 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;
         }
 
         /*
@@ -1553,7 +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;
@@ -1590,9 +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;