[PATCH] splice: add direct fd <-> fd splicing support
It's more efficient for sendfile() emulation. Basically we cache an
internal private pipe and just use that as the intermediate area for
pages. Direct splicing is not available from sys_splice(), it is only
meant to be used for sendfile() emulation.
Additional patch from Ingo Molnar to avoid the PIPE_BUFFERS loop at
exit for the normal fast path.
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7e64544..9e8e2ee 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1613,6 +1613,8 @@
loff_t *, read_descriptor_t *, read_actor_t);
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 long do_splice_direct(struct file *in, struct file *out,
+ size_t len, unsigned int flags);
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,