pipe: add pipe_buf_steal() helper

[cascardo/linux.git] / include / linux / pipe_fs_i.h

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 24f5470..bddccf0 100644 (file)
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -115,6 +115,53 @@ struct pipe_buf_operations {
        void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
 };
 
+/**
+ * pipe_buf_get - get a reference to a pipe_buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer to get a reference to
+ */
+static inline void pipe_buf_get(struct pipe_inode_info *pipe,
+                               struct pipe_buffer *buf)
+{
+       buf->ops->get(pipe, buf);
+}
+
+/**
+ * pipe_buf_release - put a reference to a pipe_buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer to put a reference to
+ */
+static inline void pipe_buf_release(struct pipe_inode_info *pipe,
+                                   struct pipe_buffer *buf)
+{
+       const struct pipe_buf_operations *ops = buf->ops;
+
+       buf->ops = NULL;
+       ops->release(pipe, buf);
+}
+
+/**
+ * pipe_buf_confirm - verify contents of the pipe buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer to confirm
+ */
+static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,
+                                  struct pipe_buffer *buf)
+{
+       return buf->ops->confirm(pipe, buf);
+}
+
+/**
+ * pipe_buf_steal - attempt to take ownership of a pipe_buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer to attempt to steal
+ */
+static inline int pipe_buf_steal(struct pipe_inode_info *pipe,
+                                struct pipe_buffer *buf)
+{
+       return buf->ops->steal(pipe, buf);
+}
+
 /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
    memory allocation, whereas PIPE_BUF makes atomicity guarantees.  */
 #define PIPE_SIZE              PAGE_SIZE
@@ -129,7 +176,6 @@ extern unsigned long pipe_user_pages_hard;
 extern unsigned long pipe_user_pages_soft;
 int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *);
 
-
 /* Drop the inode semaphore and wait for a pipe event, atomically */
 void pipe_wait(struct pipe_inode_info *pipe);