gpu: ion: several bugfixes and enhancements of ION

1. Verifying if the size of memory allocation in ion_alloc() is aligned
by PAGE_SIZE at least. If it is not, this change makes the size to be
aligned by PAGE_SIZE.

2. Unmaps all mappings to the kernel and DMA address spaces when
destroying ion_buffer in ion_buffer_destroy(). This prevents leaks in
those virtual address spaces.

3. Makes the return value of ion_alloc() to be explicit Linux error code
when it fails to allocate a buffer.

4. Makes ion_alloc() implementation simpler. Removes 'goto' statement and
relavant call to ion_buffer_put().

5. Checks if the task is valid before calling put_task_struct() due
to failure on creating a ion client in ion_client_create().

6. Returns error when buffer allocation requested by userspace is failed.

Change-Id: I4fa9859f4a0b665fcb44e5c0da43c569732e93ae
Signed-off-by: KyongHo Cho <pullip.cho@samsung.com>

diff --git a/drivers/gpu/ion/ion.c b/drivers/gpu/ion/ion.c
index 344d66d6fab2b980a047ae265ba11ecd5aedc9dc..81e64297de166722d39f21f535bafa65cc3f8799 100644 (file)
--- a/drivers/gpu/ion/ion.c
+++ b/drivers/gpu/ion/ion.c
@@ -166,6 +166,12 @@ static void ion_buffer_destroy(struct kref *kref)
        struct ion_buffer *buffer = container_of(kref, struct ion_buffer, ref);
        struct ion_device *dev = buffer->dev;
 
+       if (WARN_ON(buffer->kmap_cnt > 0))
+               buffer->heap->ops->unmap_kernel(buffer->heap, buffer);
+
+       if (WARN_ON(buffer->dmap_cnt > 0))
+               buffer->heap->ops->unmap_dma(buffer->heap, buffer);
+
        buffer->heap->ops->free(buffer);
        mutex_lock(&dev->lock);
        rb_erase(&buffer->node, &dev->buffers);
@@ -296,6 +302,11 @@ struct ion_handle *ion_alloc(struct ion_client *client, size_t len,
         * request of the caller allocate from it.  Repeat until allocate has
         * succeeded or all heaps have been tried
         */
+       if (WARN_ON(!len))
+               return ERR_PTR(-EINVAL);
+
+       len = PAGE_ALIGN(len);
+
        mutex_lock(&dev->lock);
        for (n = rb_first(&dev->heaps); n != NULL; n = rb_next(n)) {
                struct ion_heap *heap = rb_entry(n, struct ion_heap, node);
@@ -311,27 +322,26 @@ struct ion_handle *ion_alloc(struct ion_client *client, size_t len,
        }
        mutex_unlock(&dev->lock);
 
-       if (IS_ERR_OR_NULL(buffer))
+       if (buffer == NULL)
+               return ERR_PTR(-ENODEV);
+
+       if (IS_ERR(buffer))
                return ERR_PTR(PTR_ERR(buffer));
 
        handle = ion_handle_create(client, buffer);
 
-       if (IS_ERR_OR_NULL(handle))
-               goto end;
-
        /*
         * ion_buffer_create will create a buffer with a ref_cnt of 1,
         * and ion_handle_create will take a second reference, drop one here
         */
        ion_buffer_put(buffer);
 
-       mutex_lock(&client->lock);
-       ion_handle_add(client, handle);
-       mutex_unlock(&client->lock);
-       return handle;
+       if (!IS_ERR(handle)) {
+               mutex_lock(&client->lock);
+               ion_handle_add(client, handle);
+               mutex_unlock(&client->lock);
+       }
 
-end:
-       ion_buffer_put(buffer);
        return handle;
 }
 
@@ -680,7 +690,8 @@ struct ion_client *ion_client_create(struct ion_device *dev,
 
        client = kzalloc(sizeof(struct ion_client), GFP_KERNEL);
        if (!client) {
-               put_task_struct(current->group_leader);
+               if (task)
+                       put_task_struct(current->group_leader);
                return ERR_PTR(-ENOMEM);
        }
 
@@ -798,6 +809,15 @@ static void ion_vma_open(struct vm_area_struct *vma)
                vma->vm_private_data = NULL;
                return;
        }
+
+       if (!ion_handle_validate(client, handle)) {
+               ion_client_put(client);
+               vma->vm_private_data = NULL;
+               return;
+       }
+
+       ion_handle_get(handle);
+
        pr_debug("%s: %d client_cnt %d handle_cnt %d alloc_cnt %d\n",
                 __func__, __LINE__,
                 atomic_read(&client->ref.refcount),
@@ -919,7 +939,7 @@ static int ion_ioctl_share(struct file *parent, struct ion_client *client,
        struct file *file;
 
        if (fd < 0)
-               return -ENFILE;
+               return fd;
 
        file = anon_inode_getfile("ion_share_fd", &ion_share_fops,
                                  handle->buffer, O_RDWR);
@@ -948,8 +968,14 @@ static long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                        return -EFAULT;
                data.handle = ion_alloc(client, data.len, data.align,
                                             data.flags);
-               if (copy_to_user((void __user *)arg, &data, sizeof(data)))
+
+               if (IS_ERR(data.handle))
+                       return PTR_ERR(data.handle);
+
+               if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
+                       ion_free(client, data.handle);
                        return -EFAULT;
+               }
                break;
        }
        case ION_IOC_FREE: