[PATCH] introduce a "kernel-internal pipe object" abstraction

separate out the 'internal pipe object' abstraction, and make it
usable to splice. This cleans up and fixes several aspects of the
internal splice APIs and the pipe code:

 - pipes: the allocation and freeing of pipe_inode_info is now more symmetric
   and more streamlined with existing kernel practices.

 - splice: small micro-optimization: less pointer dereferencing in splice
   methods

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Update XFS for the ->splice_read/->splice_write changes.

Signed-off-by: Jens Axboe <axboe@suse.de>

2 files changed, 8 insertions, 7 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1e9ebaba07b7..7e6454454fbd 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1039,8 +1039,8 @@ struct file_operations {
         int (*check_flags)(int);
         int (*dir_notify)(struct file *filp, unsigned long arg);
         int (*flock) (struct file *, int, struct file_lock *);
-        ssize_t (*splice_write)(struct inode *, struct file *, size_t, unsigned int);
-        ssize_t (*splice_read)(struct file *, struct inode *, size_t, unsigned int);
+        ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, size_t, unsigned int);
+        ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned int);
 };
 
 struct inode_operations {
@@ -1611,8 +1611,8 @@ extern ssize_t generic_file_sendfile(struct file *, loff_t *, size_t, read_actor
 extern void do_generic_mapping_read(struct address_space *mapping,
                                     struct file_ra_state *, struct file *,
                                     loff_t *, read_descriptor_t *, read_actor_t);
-extern ssize_t generic_file_splice_read(struct file *, struct inode *, size_t, unsigned int);
-extern ssize_t generic_file_splice_write(struct inode *, struct file *, size_t, unsigned int);
+extern ssize_t generic_file_splice_read(struct file *, struct pipe_inode_info *, size_t, unsigned int);
+extern ssize_t generic_file_splice_write(struct pipe_inode_info *, struct file *, size_t, unsigned int);
 extern void
 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
 extern ssize_t generic_file_readv(struct file *filp, const struct iovec *iov, 
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index ec384958d509..9cf99cb34c15 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -36,6 +36,7 @@ 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
@@ -53,10 +54,10 @@ struct pipe_inode_info {
 #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 inode* pipe_new(struct inode* inode);
-void free_pipe_info(struct inode* inode);
+struct pipe_inode_info * alloc_pipe_info(struct inode * inode);
+void free_pipe_info(struct inode * inode);
 
 /*
  * splice is tied to pipes as a transport (at least for now), so we'll just