[PATCH] splice: add a SPLICE_F_MORE flag

This lets userspace indicate whether more data will be coming in a
subsequent splice call.
Signed-off-by: NJens Axboe <axboe@suse.de>

fs/splice.c

@@ -354,6 +354,7 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
 	unsigned int offset;
 	ssize_t ret;
 	void *ptr;
+	int more;
 
 	/*
 	 * sub-optimal, but we are limited by the pipe ->map. we don't
@@ -366,9 +367,9 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
 		return PTR_ERR(ptr);
 
 	offset = pos & ~PAGE_CACHE_MASK;
+	more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
 
-	ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,
-					sd->len < sd->total_len);
+	ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,more);
 
 	buf->ops->unmap(info, buf);
 	if (ret == sd->len)

include/linux/pipe_fs_i.h

@@ -62,5 +62,6 @@ 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 */
 
 #endif