From 5274f052e7b3dbd81935772eb551dfd0325dfa9d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 30 Mar 2006 15:15:30 +0200 Subject: [PATCH] Introduce sys_splice() system call This adds support for the sys_splice system call. Using a pipe as a transport, it can connect to files or sockets (latter as output only). From the splice.c comments: "splice": joining two ropes together by interweaving their strands. This is the "extended pipe" functionality, where a pipe is used as an arbitrary in-memory buffer. Think of a pipe as a small kernel buffer that you can use to transfer data from one end to the other. The traditional unix read/write is extended with a "splice()" operation that transfers data buffers to or from a pipe buffer. Named by Larry McVoy, original implementation from Linus, extended by Jens to support splicing to files and fixing the initial implementation bugs. Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds --- include/linux/fs.h | 4 ++++ include/linux/syscalls.h | 2 ++ 2 files changed, 6 insertions(+) (limited to 'include/linux') diff --git a/include/linux/fs.h b/include/linux/fs.h index 408fe89498f4..20fa5f6d7269 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1032,6 +1032,8 @@ 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); }; struct inode_operations { @@ -1609,6 +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 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/syscalls.h b/include/linux/syscalls.h index e487e3b60f60..e78ffc7d5b56 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -569,5 +569,7 @@ asmlinkage long compat_sys_newfstatat(unsigned int dfd, char __user * filename, asmlinkage long compat_sys_openat(unsigned int dfd, const char __user *filename, int flags, int mode); asmlinkage long sys_unshare(unsigned long unshare_flags); +asmlinkage long sys_splice(int fdin, int fdout, size_t len, + unsigned int flags); #endif -- cgit v1.2.3 From 5abc97aa25b2c41413b3a520faee83f2282d9f18 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 30 Mar 2006 15:16:46 +0200 Subject: [PATCH] splice: add support for SPLICE_F_MOVE flag This enables the caller to migrate pages from one address space page cache to another. In buzz word marketing, you can do zero-copy file copies! Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds --- include/linux/pipe_fs_i.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index b12e59c75752..75c7f55023ab 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -9,6 +9,7 @@ struct pipe_buffer { struct page *page; unsigned int offset, len; struct pipe_buf_operations *ops; + unsigned int stolen; }; struct pipe_buf_operations { @@ -16,6 +17,7 @@ struct pipe_buf_operations { void * (*map)(struct file *, struct pipe_inode_info *, struct pipe_buffer *); void (*unmap)(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 *); }; struct pipe_inode_info { @@ -53,4 +55,10 @@ void pipe_wait(struct inode * inode); struct inode* pipe_new(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 + * add the splice flags here. + */ +#define SPLICE_F_MOVE (0x01) /* move pages instead of copying */ + #endif -- cgit v1.2.3