ion: minor clean up

-- init rb nodes in ion_handle_create
-- in ion_handle_destroy, check that a node belongs to a tree before removing
   it (safety check, does not happen right now)
-- mark as static functions used only inside ion.c
-- update comments to ion_share() with a relevant blurb from the implementation
-- other minor updates/typo fixes to comments

Signed-off-by: Iliyan Malchev <malchev@google.com>

diff --git a/drivers/gpu/ion/ion.c b/drivers/gpu/ion/ion.c
index 9cb5b25..37b23af 100644 (file)
--- a/drivers/gpu/ion/ion.c
+++ b/drivers/gpu/ion/ion.c
@@ -131,7 +131,7 @@ static void ion_buffer_add(struct ion_device *dev,
 }
 
 /* this function should only be called while dev->lock is held */
-struct ion_buffer *ion_buffer_create(struct ion_heap *heap,
+static struct ion_buffer *ion_buffer_create(struct ion_heap *heap,
                                     struct ion_device *dev,
                                     unsigned long len,
                                     unsigned long align,
@@ -181,7 +181,7 @@ static int ion_buffer_put(struct ion_buffer *buffer)
        return kref_put(&buffer->ref, ion_buffer_destroy);
 }
 
-struct ion_handle *ion_handle_create(struct ion_client *client,
+static struct ion_handle *ion_handle_create(struct ion_client *client,
                                     struct ion_buffer *buffer)
 {
        struct ion_handle *handle;
@@ -190,6 +190,7 @@ struct ion_handle *ion_handle_create(struct ion_client *client,
        if (!handle)
                return ERR_PTR(-ENOMEM);
        kref_init(&handle->ref);
+       rb_init_node(&handle->node);
        handle->client = client;
        ion_buffer_get(buffer);
        handle->buffer = buffer;
@@ -205,7 +206,8 @@ static void ion_handle_destroy(struct kref *kref)
         */
        ion_buffer_put(handle->buffer);
        mutex_lock(&handle->client->lock);
-       rb_erase(&handle->node, &handle->client->handles);
+       if (!RB_EMPTY_NODE(&handle->node))
+               rb_erase(&handle->node, &handle->client->handles);
        mutex_unlock(&handle->client->lock);
        kfree(handle);
 }
@@ -239,7 +241,7 @@ static struct ion_handle *ion_handle_lookup(struct ion_client *client,
        return NULL;
 }
 
-bool ion_handle_validate(struct ion_client *client, struct ion_handle *handle)
+static bool ion_handle_validate(struct ion_client *client, struct ion_handle *handle)
 {
        struct rb_node *n = client->handles.rb_node;
 
@@ -351,7 +353,7 @@ void ion_free(struct ion_client *client, struct ion_handle *handle)
 static void ion_client_get(struct ion_client *client);
 static int ion_client_put(struct ion_client *client);
 
-bool _ion_map(int *buffer_cnt, int *handle_cnt)
+static bool _ion_map(int *buffer_cnt, int *handle_cnt)
 {
        bool map;
 
@@ -367,7 +369,7 @@ bool _ion_map(int *buffer_cnt, int *handle_cnt)
        return map;
 }
 
-bool _ion_unmap(int *buffer_cnt, int *handle_cnt)
+static bool _ion_unmap(int *buffer_cnt, int *handle_cnt)
 {
        BUG_ON(*handle_cnt == 0);
        (*handle_cnt)--;
@@ -522,7 +524,7 @@ struct ion_buffer *ion_share(struct ion_client *client,
                return ERR_PTR(-EINVAL);
        }
 
-       /* don't not take an extra refernce here, the burden is on the caller
+       /* do not take an extra reference here, the burden is on the caller
         * to make sure the buffer doesn't go away while it's passing it
         * to another client -- ion_free should not be called on this handle
         * until the buffer has been imported into the other client
@@ -897,7 +899,7 @@ err1:
        /* drop the reference to the handle */
        ion_handle_put(handle);
 err:
-       /* drop the refernce to the client */
+       /* drop the reference to the client */
        ion_client_put(client);
        return ret;
 }

diff --git a/include/linux/ion.h b/include/linux/ion.h
index 111982f..aed8349 100644 (file)
--- a/include/linux/ion.h
+++ b/include/linux/ion.h
@@ -186,9 +186,14 @@ void ion_unmap_dma(struct ion_client *client, struct ion_handle *handle);
  * @client:    the client
  * @handle:    the handle to share
  *
- * Given a handle, return a buffer which exists in a global name
- * space and can be passed to other clients.  Should be passed into ion_import
+ * Given a handle, return a buffer, which exists in a global name
+ * space, and can be passed to other clients.  Should be passed into ion_import
  * to obtain a new handle for this buffer.
+ *
+ * NOTE: This function does do not an extra reference.  The burden is on the
+ * caller to make sure the buffer doesn't go away while it's being passed to
+ * another client.  That is, ion_free should not be called on this handle until
+ * the buffer has been imported into the other client.
  */
 struct ion_buffer *ion_share(struct ion_client *client,
                             struct ion_handle *handle);