+static inline unsigned int pipe_update_tail(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf,
+ unsigned int tail)
+{
+ pipe_buf_release(pipe, buf);
+
+ /*
+ * If the pipe has a watch_queue, we need additional protection
+ * by the spinlock because notifications get posted with only
+ * this spinlock, no mutex
+ */
+ if (pipe_has_watch_queue(pipe)) {
+ spin_lock_irq(&pipe->rd_wait.lock);
+#ifdef CONFIG_WATCH_QUEUE
+ if (buf->flags & PIPE_BUF_FLAG_LOSS)
+ pipe->note_loss = true;
+#endif
+ pipe->tail = ++tail;
+ spin_unlock_irq(&pipe->rd_wait.lock);
+ return tail;
+ }
+
+ /*
+ * Without a watch_queue, we can simply increment the tail
+ * without the spinlock - the mutex is enough.
+ */
+ pipe->tail = ++tail;
+ return tail;
+}
+