1 files changed, 26 insertions, 4 deletions

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 0008d4bd4059..ea4f7cd7bfd8 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -5,8 +5,9 @@
 
 #define PIPE_BUFFERS (16)
 
-#define PIPE_BUF_FLAG_STOLEN    0x01
-#define PIPE_BUF_FLAG_LRU       0x02
+#define PIPE_BUF_FLAG_LRU       0x01    /* page is on the LRU */
+#define PIPE_BUF_FLAG_ATOMIC    0x02    /* was atomically mapped */
+#define PIPE_BUF_FLAG_GIFT      0x04    /* page is a gift */
 
 struct pipe_buffer {
         struct page *page;
@@ -15,10 +16,23 @@ struct pipe_buffer {
         unsigned int flags;
 };
 
+/*
+ * Note on the nesting of these functions:
+ *
+ * ->pin()
+ *      ->steal()
+ *      ...
+ *      ->map()
+ *      ...
+ *      ->unmap()
+ *
+ * That is, ->map() must be called on a pinned buffer, same goes for ->steal().
+ */
 struct pipe_buf_operations {
         int can_merge;
-        void * (*map)(struct file *, struct pipe_inode_info *, struct pipe_buffer *);
-        void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *);
+        void * (*map)(struct pipe_inode_info *, struct pipe_buffer *, int);
+        void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *, void *);
+        int (*pin)(struct pipe_inode_info *, struct pipe_buffer *);
         void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
         int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
         void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
@@ -51,6 +65,13 @@ struct pipe_inode_info * alloc_pipe_info(struct inode * inode);
 void free_pipe_info(struct inode * inode);
 void __free_pipe_info(struct pipe_inode_info *);
 
+/* Generic pipe buffer ops functions */
+void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int);
+void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *);
+void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
+
 /*
  * splice is tied to pipes as a transport (at least for now), so we'll just
  * add the splice flags here.
@@ -60,6 +81,7 @@ void __free_pipe_info(struct pipe_inode_info *);
                                  /* we may still block on the fd we splice */
                                  /* from/to, of course */
 #define SPLICE_F_MORE   (0x04)  /* expect more data */
+#define SPLICE_F_GIFT   (0x08)  /* pages passed in are a gift */
 
 /*
  * Passed to the actors