[PATCH] pipe: enable atomic copying of pipe data to/from user space

[safe/jmp/linux-2.6] / include / linux / pipe_fs_i.h

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 3286500..4c05449 100644 (file)
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -5,18 +5,36 @@
 
 #define PIPE_BUFFERS (16)
 
+#define PIPE_BUF_FLAG_LRU      0x01    /* page is on the LRU */
+#define PIPE_BUF_FLAG_ATOMIC   0x02    /* was atomically mapped */
+
 struct pipe_buffer {
        struct page *page;
        unsigned int offset, len;
        struct pipe_buf_operations *ops;
+       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 *);
 };
 
 struct pipe_inode_info {
@@ -32,27 +50,25 @@ struct pipe_inode_info {
        unsigned int w_counter;
        struct fasync_struct *fasync_readers;
        struct fasync_struct *fasync_writers;
+       struct inode *inode;
 };
 
 /* 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
 
-#define PIPE_MUTEX(inode)      (&(inode).i_mutex)
-#define PIPE_WAIT(inode)       (&(inode).i_pipe->wait)
-#define PIPE_READERS(inode)    ((inode).i_pipe->readers)
-#define PIPE_WRITERS(inode)    ((inode).i_pipe->writers)
-#define PIPE_WAITING_WRITERS(inode)    ((inode).i_pipe->waiting_writers)
-#define PIPE_RCOUNTER(inode)   ((inode).i_pipe->r_counter)
-#define PIPE_WCOUNTER(inode)   ((inode).i_pipe->w_counter)
-#define PIPE_FASYNC_READERS(inode)     (&((inode).i_pipe->fasync_readers))
-#define PIPE_FASYNC_WRITERS(inode)     (&((inode).i_pipe->fasync_writers))
-
 /* Drop the inode semaphore and wait for a pipe event, atomically */
-void pipe_wait(struct inode * inode);
+void pipe_wait(struct pipe_inode_info *pipe);
+
+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 *);
 
-struct inode* pipe_new(struct inode* inode);
-void free_pipe_info(struct inode* inode);
+/* 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 *);
 
 /*
  * splice is tied to pipes as a transport (at least for now), so we'll just
@@ -62,5 +78,23 @@ void free_pipe_info(struct inode* inode);
 #define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
                                 /* we may still block on the fd we splice */
                                 /* from/to, of course */
+#define SPLICE_F_MORE  (0x04)  /* expect more data */
+
+/*
+ * Passed to the actors
+ */
+struct splice_desc {
+       unsigned int len, total_len;    /* current and remaining length */
+       unsigned int flags;             /* splice flags */
+       struct file *file;              /* file to read/write */
+       loff_t pos;                     /* file position */
+};
+
+typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
+                          struct splice_desc *);
+
+extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
+                               loff_t *, size_t, unsigned int,
+                               splice_actor *);
 
 #endif