linux-master/fs/splice.c

6  * an arbitrary in-memory buffer. Think of a pipe as a small kernel
90 		 * If we succeeded in removing the mapping, set LRU flag
117  * is a page cache page, IO may be in flight.
303  * @in: The file to read from
321 ssize_t copy_splice_read(struct file *in, loff_t *ppos,
363 	init_sync_kiocb(&kiocb, in);
365 	ret = call_read_iter(in, &kiocb, &to);
373 	 * Callers of ->splice_read() expect -EAGAIN on "can't put anything in
434  *    destination.  It returns when there's no more buffers left in
623  * @ppos:	position in @out
656  * @ppos:	position in @out
790  * @ppos:	position in @out
959 static ssize_t do_splice_read(struct file *in, loff_t *ppos,
965 	if (unlikely(!(in->f_mode & FMODE_READ)))
977 	if (unlikely(!in->f_op->splice_read))
978 		return warn_unsupported(in, "read");
983 	if ((in->f_flags & O_DIRECT) || IS_DAX(in->f_mapping->host))
984 		return copy_splice_read(in, ppos, pipe, len, flags);
985 	return in->f_op->splice_read(in, ppos, pipe, len, flags);
990  * @in:		File to splice from
1003 ssize_t vfs_splice_read(struct file *in, loff_t *ppos,
1009 	ret = rw_verify_area(READ, in, ppos, len);
1013 	return do_splice_read(in, ppos, pipe, len, flags);
1019  * @in:		file to splice from
1026  *    pipe is cached in the process, and reused during the lifetime of
1030 ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
1043 	if (unlikely(!(in->f_mode & FMODE_LSEEK)))
1047 	 * neither in nor out is a pipe, setup an internal pipe attached to
1048 	 * 'out' and transfer the wanted data from 'in' to 'out' through that
1089 		ret = do_splice_read(in, &pos, pipe, len, flags);
1105 		 * must not do the output in nonblocking mode as then we
1106 		 * could get stuck data in the internal pipe:
1126 	file_accessed(in);
1141 	 * the pipe buffers in question:
1185 static ssize_t do_splice_direct_actor(struct file *in, loff_t *ppos,
1207 	ret = splice_direct_to_actor(in, &sd, actor);
1215  * @in:		file to splice from
1224  *    doing it in the application would incur an extra system call
1225  *    (splice in + splice out, as compared to just sendfile()). So this helper
1230 ssize_t do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
1233 	return do_splice_direct_actor(in, ppos, out, opos, len, flags,
1240  * @in:		file to splice from
1253 ssize_t splice_file_range(struct file *in, loff_t *ppos, struct file *out,
1258 	return do_splice_direct_actor(in, ppos, out, opos,
1285 ssize_t splice_file_to_pipe(struct file *in,
1295 		ret = do_splice_read(in, offset, opipe, len, flags);
1305 ssize_t do_splice(struct file *in, loff_t *off_in, struct file *out,
1313 	if (unlikely(!(in->f_mode & FMODE_READ) ||
1317 	ipipe = get_pipe_info(in, true);
1328 		if ((in->f_flags | out->f_flags) & O_NONBLOCK)
1350 		if (in->f_flags & O_NONBLOCK)
1365 			if (!(in->f_mode & FMODE_PREAD))
1369 			offset = in->f_pos;
1372 		ret = rw_verify_area(READ, in, &offset, len);
1379 		ret = splice_file_to_pipe(in, opipe, &offset, len, flags);
1382 			in->f_pos = offset;
1391 		 * Generate modify out before access in:
1396 		fsnotify_access(in);
1402 static ssize_t __do_splice(struct file *in, loff_t __user *off_in,
1411 	ipipe = get_pipe_info(in, true);
1417 		pipe_clear_nowait(in);
1436 	ret = do_splice(in, __off_in, out, __off_out, len, flags);
1586  * or nasty vm tricks. We simply map in the user memory and fill them into
1638 	struct fd in, out;
1648 	in = fdget(fd_in);
1649 	if (in.file) {
1652 			error = __do_splice(in.file, off_in, out.file, off_out,
1656 		fdput(in);
1862 	 * If we put data in the output pipe, wakeup any potential readers.
1953 	 * If we put data in the output pipe, wakeup any potential readers.
1963  * any data, it simply references the 'in' pages on the 'out' pipe.
1967 ssize_t do_tee(struct file *in, struct file *out, size_t len,
1970 	struct pipe_inode_info *ipipe = get_pipe_info(in, true);
1974 	if (unlikely(!(in->f_mode & FMODE_READ) ||
1983 		if ((in->f_flags | out->f_flags) & O_NONBLOCK)
1999 		fsnotify_access(in);
2008 	struct fd in, out;
2018 	in = fdget(fdin);
2019 	if (in.file) {
2022 			error = do_tee(in.file, out.file, len, flags);
2025  		fdput(in);