From cbb7e577e732f576b9f399bc2600bdc0626c68dc Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@suse.de>
Date: Tue, 11 Apr 2006 14:57:50 +0200
Subject: [PATCH] splice: pass offset around for ->splice_read() and
 ->splice_write()

We need not use ->f_pos as the offset for the file input/output. If the
user passed an offset pointer in through sys_splice(), just use that and
leave ->f_pos alone.

Signed-off-by: Jens Axboe <axboe@suse.de>
---
 fs/splice.c                  | 86 ++++++++++++++++++++++----------------------
 fs/xfs/linux-2.6/xfs_file.c  | 12 ++++---
 fs/xfs/linux-2.6/xfs_lrw.c   | 14 ++++----
 fs/xfs/linux-2.6/xfs_lrw.h   |  4 +--
 fs/xfs/linux-2.6/xfs_vnode.h | 12 +++----
 include/linux/fs.h           | 12 +++----
 6 files changed, 74 insertions(+), 66 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index e50a460239dd..5d3eda64703b 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -231,8 +231,9 @@ static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
 }
 
 static int
-__generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe,
-			   size_t len, unsigned int flags)
+__generic_file_splice_read(struct file *in, loff_t *ppos,
+			   struct pipe_inode_info *pipe, size_t len,
+			   unsigned int flags)
 {
 	struct address_space *mapping = in->f_mapping;
 	unsigned int offset, nr_pages;
@@ -241,8 +242,8 @@ __generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe,
 	pgoff_t index;
 	int i, error;
 
-	index = in->f_pos >> PAGE_CACHE_SHIFT;
-	offset = in->f_pos & ~PAGE_CACHE_MASK;
+	index = *ppos >> PAGE_CACHE_SHIFT;
+	offset = *ppos & ~PAGE_CACHE_MASK;
 	nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 
 	if (nr_pages > PIPE_BUFFERS)
@@ -348,8 +349,9 @@ fill_it:
  *
  * Will read pages from given file and fill them into a pipe.
  */
-ssize_t generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe,
-				 size_t len, unsigned int flags)
+ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
+				 struct pipe_inode_info *pipe, size_t len,
+				 unsigned int flags)
 {
 	ssize_t spliced;
 	int ret;
@@ -358,12 +360,12 @@ ssize_t generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe,
 	spliced = 0;
 
 	while (len) {
-		ret = __generic_file_splice_read(in, pipe, len, flags);
+		ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
 
 		if (ret <= 0)
 			break;
 
-		in->f_pos += ret;
+		*ppos += ret;
 		len -= ret;
 		spliced += ret;
 
@@ -561,7 +563,7 @@ typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
  * to the wanted destination. See pipe_to_file/pipe_to_sendpage above.
  */
 static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
-			      size_t len, unsigned int flags,
+			      loff_t *ppos, size_t len, unsigned int flags,
 			      splice_actor *actor)
 {
 	int ret, do_wakeup, err;
@@ -573,7 +575,7 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
 	sd.total_len = len;
 	sd.flags = flags;
 	sd.file = out;
-	sd.pos = out->f_pos;
+	sd.pos = *ppos;
 
 	if (pipe->inode)
 		mutex_lock(&pipe->inode->i_mutex);
@@ -656,9 +658,7 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
 		kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
 	}
 
-	out->f_pos = sd.pos;
 	return ret;
-
 }
 
 /**
@@ -674,12 +674,12 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
  */
 ssize_t
 generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
-			  size_t len, unsigned int flags)
+			  loff_t *ppos, size_t len, unsigned int flags)
 {
 	struct address_space *mapping = out->f_mapping;
 	ssize_t ret;
 
-	ret = move_from_pipe(pipe, out, len, flags, pipe_to_file);
+	ret = move_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
 
 	/*
 	 * If file or inode is SYNC and we actually wrote some data, sync it.
@@ -715,9 +715,9 @@ EXPORT_SYMBOL(generic_file_splice_write);
  *
  */
 ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out,
-				size_t len, unsigned int flags)
+				loff_t *ppos, size_t len, unsigned int flags)
 {
-	return move_from_pipe(pipe, out, len, flags, pipe_to_sendpage);
+	return move_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage);
 }
 
 EXPORT_SYMBOL(generic_splice_sendpage);
@@ -726,9 +726,8 @@ EXPORT_SYMBOL(generic_splice_sendpage);
  * Attempt to initiate a splice from pipe to file.
  */
 static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
-			   size_t len, unsigned int flags)
+			   loff_t *ppos, size_t len, unsigned int flags)
 {
-	loff_t pos;
 	int ret;
 
 	if (unlikely(!out->f_op || !out->f_op->splice_write))
@@ -737,22 +736,21 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
 	if (unlikely(!(out->f_mode & FMODE_WRITE)))
 		return -EBADF;
 
-	pos = out->f_pos;
-
-	ret = rw_verify_area(WRITE, out, &pos, len);
+	ret = rw_verify_area(WRITE, out, ppos, len);
 	if (unlikely(ret < 0))
 		return ret;
 
-	return out->f_op->splice_write(pipe, out, len, flags);
+	return out->f_op->splice_write(pipe, out, ppos, len, flags);
 }
 
 /*
  * Attempt to initiate a splice from a file to a pipe.
  */
-static long do_splice_to(struct file *in, struct pipe_inode_info *pipe,
-			 size_t len, unsigned int flags)
+static long do_splice_to(struct file *in, loff_t *ppos,
+			 struct pipe_inode_info *pipe, size_t len,
+			 unsigned int flags)
 {
-	loff_t pos, isize, left;
+	loff_t isize, left;
 	int ret;
 
 	if (unlikely(!in->f_op || !in->f_op->splice_read))
@@ -761,28 +759,27 @@ static long do_splice_to(struct file *in, struct pipe_inode_info *pipe,
 	if (unlikely(!(in->f_mode & FMODE_READ)))
 		return -EBADF;
 
-	pos = in->f_pos;
-
-	ret = rw_verify_area(READ, in, &pos, len);
+	ret = rw_verify_area(READ, in, ppos, len);
 	if (unlikely(ret < 0))
 		return ret;
 
 	isize = i_size_read(in->f_mapping->host);
-	if (unlikely(in->f_pos >= isize))
+	if (unlikely(*ppos >= isize))
 		return 0;
 	
-	left = isize - in->f_pos;
+	left = isize - *ppos;
 	if (unlikely(left < len))
 		len = left;
 
-	return in->f_op->splice_read(in, pipe, len, flags);
+	return in->f_op->splice_read(in, ppos, pipe, len, flags);
 }
 
-long do_splice_direct(struct file *in, struct file *out, size_t len,
-		      unsigned int flags)
+long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
+		      size_t len, unsigned int flags)
 {
 	struct pipe_inode_info *pipe;
 	long ret, bytes;
+	loff_t out_off;
 	umode_t i_mode;
 	int i;
 
@@ -820,6 +817,7 @@ long do_splice_direct(struct file *in, struct file *out, size_t len,
 	 */
 	ret = 0;
 	bytes = 0;
+	out_off = 0;
 
 	while (len) {
 		size_t read_len, max_read_len;
@@ -829,7 +827,7 @@ long do_splice_direct(struct file *in, struct file *out, size_t len,
 		 */
 		max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE));
 
-		ret = do_splice_to(in, pipe, max_read_len, flags);
+		ret = do_splice_to(in, ppos, pipe, max_read_len, flags);
 		if (unlikely(ret < 0))
 			goto out_release;
 
@@ -840,7 +838,7 @@ long do_splice_direct(struct file *in, struct file *out, size_t len,
 		 * must not do the output in nonblocking mode as then we
 		 * could get stuck data in the internal pipe:
 		 */
-		ret = do_splice_from(pipe, out, read_len,
+		ret = do_splice_from(pipe, out, &out_off, read_len,
 				     flags & ~SPLICE_F_NONBLOCK);
 		if (unlikely(ret < 0))
 			goto out_release;
@@ -898,6 +896,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 		      size_t len, unsigned int flags)
 {
 	struct pipe_inode_info *pipe;
+	loff_t offset, *off;
 
 	pipe = in->f_dentry->d_inode->i_pipe;
 	if (pipe) {
@@ -906,12 +905,13 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 		if (off_out) {
 			if (out->f_op->llseek == no_llseek)
 				return -EINVAL;
-			if (copy_from_user(&out->f_pos, off_out,
-					   sizeof(loff_t)))
+			if (copy_from_user(&offset, off_out, sizeof(loff_t)))
 				return -EFAULT;
-		}
+			off = &offset;
+		} else
+			off = &out->f_pos;
 
-		return do_splice_from(pipe, out, len, flags);
+		return do_splice_from(pipe, out, off, len, flags);
 	}
 
 	pipe = out->f_dentry->d_inode->i_pipe;
@@ -921,11 +921,13 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 		if (off_in) {
 			if (in->f_op->llseek == no_llseek)
 				return -EINVAL;
-			if (copy_from_user(&in->f_pos, off_in, sizeof(loff_t)))
+			if (copy_from_user(&offset, off_in, sizeof(loff_t)))
 				return -EFAULT;
-		}
+			off = &offset;
+		} else
+			off = &in->f_pos;
 
-		return do_splice_to(in, pipe, len, flags);
+		return do_splice_to(in, off, pipe, len, flags);
 	}
 
 	return -EINVAL;
diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index 269721af02f3..c847416f6d10 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -252,6 +252,7 @@ xfs_file_sendfile_invis(
 STATIC ssize_t
 xfs_file_splice_read(
 	struct file		*infilp,
+	loff_t			*ppos,
 	struct pipe_inode_info	*pipe,
 	size_t			len,
 	unsigned int		flags)
@@ -259,13 +260,14 @@ xfs_file_splice_read(
 	vnode_t			*vp = vn_from_inode(infilp->f_dentry->d_inode);
 	ssize_t			rval;
 
-	VOP_SPLICE_READ(vp, infilp, pipe, len, flags, 0, NULL, rval);
+	VOP_SPLICE_READ(vp, infilp, ppos, pipe, len, flags, 0, NULL, rval);
 	return rval;
 }
 
 STATIC ssize_t
 xfs_file_splice_read_invis(
 	struct file		*infilp,
+	loff_t			*ppos,
 	struct pipe_inode_info	*pipe,
 	size_t			len,
 	unsigned int		flags)
@@ -273,7 +275,7 @@ xfs_file_splice_read_invis(
 	vnode_t			*vp = vn_from_inode(infilp->f_dentry->d_inode);
 	ssize_t			rval;
 
-	VOP_SPLICE_READ(vp, infilp, pipe, len, flags, IO_INVIS, NULL, rval);
+	VOP_SPLICE_READ(vp, infilp, ppos, pipe, len, flags, IO_INVIS, NULL, rval);
 	return rval;
 }
 
@@ -281,13 +283,14 @@ STATIC ssize_t
 xfs_file_splice_write(
 	struct pipe_inode_info	*pipe,
 	struct file		*outfilp,
+	loff_t			*ppos,
 	size_t			len,
 	unsigned int		flags)
 {
 	vnode_t			*vp = vn_from_inode(outfilp->f_dentry->d_inode);
 	ssize_t			rval;
 
-	VOP_SPLICE_WRITE(vp, pipe, outfilp, len, flags, 0, NULL, rval);
+	VOP_SPLICE_WRITE(vp, pipe, outfilp, ppos, len, flags, 0, NULL, rval);
 	return rval;
 }
 
@@ -295,13 +298,14 @@ STATIC ssize_t
 xfs_file_splice_write_invis(
 	struct pipe_inode_info	*pipe,
 	struct file		*outfilp,
+	loff_t			*ppos,
 	size_t			len,
 	unsigned int		flags)
 {
 	vnode_t			*vp = vn_from_inode(outfilp->f_dentry->d_inode);
 	ssize_t			rval;
 
-	VOP_SPLICE_WRITE(vp, pipe, outfilp, len, flags, IO_INVIS, NULL, rval);
+	VOP_SPLICE_WRITE(vp, pipe, outfilp, ppos, len, flags, IO_INVIS, NULL, rval);
 	return rval;
 }
 
diff --git a/fs/xfs/linux-2.6/xfs_lrw.c b/fs/xfs/linux-2.6/xfs_lrw.c
index 74a52937f208..67efe3308980 100644
--- a/fs/xfs/linux-2.6/xfs_lrw.c
+++ b/fs/xfs/linux-2.6/xfs_lrw.c
@@ -338,6 +338,7 @@ ssize_t
 xfs_splice_read(
 	bhv_desc_t		*bdp,
 	struct file		*infilp,
+	loff_t			*ppos,
 	struct pipe_inode_info	*pipe,
 	size_t			count,
 	int			flags,
@@ -360,7 +361,7 @@ xfs_splice_read(
 		int error;
 
 		error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp),
-					infilp->f_pos, count,
+					*ppos, count,
 					FILP_DELAY_FLAG(infilp), &locktype);
 		if (error) {
 			xfs_iunlock(ip, XFS_IOLOCK_SHARED);
@@ -368,8 +369,8 @@ xfs_splice_read(
 		}
 	}
 	xfs_rw_enter_trace(XFS_SPLICE_READ_ENTER, &ip->i_iocore,
-			   pipe, count, infilp->f_pos, ioflags);
-	ret = generic_file_splice_read(infilp, pipe, count, flags);
+			   pipe, count, *ppos, ioflags);
+	ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
 	if (ret > 0)
 		XFS_STATS_ADD(xs_read_bytes, ret);
 
@@ -382,6 +383,7 @@ xfs_splice_write(
 	bhv_desc_t		*bdp,
 	struct pipe_inode_info	*pipe,
 	struct file		*outfilp,
+	loff_t			*ppos,
 	size_t			count,
 	int			flags,
 	int			ioflags,
@@ -403,7 +405,7 @@ xfs_splice_write(
 		int error;
 
 		error = XFS_SEND_DATA(mp, DM_EVENT_WRITE, BHV_TO_VNODE(bdp),
-					outfilp->f_pos, count,
+					*ppos, count,
 					FILP_DELAY_FLAG(outfilp), &locktype);
 		if (error) {
 			xfs_iunlock(ip, XFS_IOLOCK_EXCL);
@@ -411,8 +413,8 @@ xfs_splice_write(
 		}
 	}
 	xfs_rw_enter_trace(XFS_SPLICE_WRITE_ENTER, &ip->i_iocore,
-			   pipe, count, outfilp->f_pos, ioflags);
-	ret = generic_file_splice_write(pipe, outfilp, count, flags);
+			   pipe, count, *ppos, ioflags);
+	ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
 	if (ret > 0)
 		XFS_STATS_ADD(xs_write_bytes, ret);
 
diff --git a/fs/xfs/linux-2.6/xfs_lrw.h b/fs/xfs/linux-2.6/xfs_lrw.h
index 55c689a86ad2..8f4539952350 100644
--- a/fs/xfs/linux-2.6/xfs_lrw.h
+++ b/fs/xfs/linux-2.6/xfs_lrw.h
@@ -93,11 +93,11 @@ extern ssize_t xfs_write(struct bhv_desc *, struct kiocb *,
 extern ssize_t xfs_sendfile(struct bhv_desc *, struct file *,
 				loff_t *, int, size_t, read_actor_t,
 				void *, struct cred *);
-extern ssize_t xfs_splice_read(struct bhv_desc *, struct file *,
+extern ssize_t xfs_splice_read(struct bhv_desc *, struct file *, loff_t *,
 				struct pipe_inode_info *, size_t, int, int,
 				struct cred *);
 extern ssize_t xfs_splice_write(struct bhv_desc *, struct pipe_inode_info *,
-				struct file *, size_t, int, int,
+				struct file *, loff_t *, size_t, int, int,
 				struct cred *);
 
 #endif	/* __XFS_LRW_H__ */
diff --git a/fs/xfs/linux-2.6/xfs_vnode.h b/fs/xfs/linux-2.6/xfs_vnode.h
index 88b09f186289..2a8e16c22353 100644
--- a/fs/xfs/linux-2.6/xfs_vnode.h
+++ b/fs/xfs/linux-2.6/xfs_vnode.h
@@ -173,11 +173,11 @@ typedef ssize_t (*vop_write_t)(bhv_desc_t *, struct kiocb *,
 typedef ssize_t (*vop_sendfile_t)(bhv_desc_t *, struct file *,
 				loff_t *, int, size_t, read_actor_t,
 				void *, struct cred *);
-typedef ssize_t (*vop_splice_read_t)(bhv_desc_t *, struct file *,
+typedef ssize_t (*vop_splice_read_t)(bhv_desc_t *, struct file *, loff_t *,
 				struct pipe_inode_info *, size_t, int, int,
 				struct cred *);
 typedef ssize_t (*vop_splice_write_t)(bhv_desc_t *, struct pipe_inode_info *,
-				struct file *, size_t, int, int,
+				struct file *, loff_t *, size_t, int, int,
 				struct cred *);
 typedef int	(*vop_ioctl_t)(bhv_desc_t *, struct inode *, struct file *,
 				int, unsigned int, void __user *);
@@ -284,10 +284,10 @@ typedef struct vnodeops {
 	rv = _VOP_(vop_write, vp)((vp)->v_fbhv,file,iov,segs,offset,ioflags,cr)
 #define VOP_SENDFILE(vp,f,off,ioflags,cnt,act,targ,cr,rv)		\
 	rv = _VOP_(vop_sendfile, vp)((vp)->v_fbhv,f,off,ioflags,cnt,act,targ,cr)
-#define VOP_SPLICE_READ(vp,f,pipe,cnt,fl,iofl,cr,rv)			\
-	rv = _VOP_(vop_splice_read, vp)((vp)->v_fbhv,f,pipe,cnt,fl,iofl,cr)
-#define VOP_SPLICE_WRITE(vp,f,pipe,cnt,fl,iofl,cr,rv)			\
-	rv = _VOP_(vop_splice_write, vp)((vp)->v_fbhv,f,pipe,cnt,fl,iofl,cr)
+#define VOP_SPLICE_READ(vp,f,o,pipe,cnt,fl,iofl,cr,rv)			\
+	rv = _VOP_(vop_splice_read, vp)((vp)->v_fbhv,f,o,pipe,cnt,fl,iofl,cr)
+#define VOP_SPLICE_WRITE(vp,f,o,pipe,cnt,fl,iofl,cr,rv)			\
+	rv = _VOP_(vop_splice_write, vp)((vp)->v_fbhv,f,o,pipe,cnt,fl,iofl,cr)
 #define VOP_BMAP(vp,of,sz,rw,b,n,rv)					\
 	rv = _VOP_(vop_bmap, vp)((vp)->v_fbhv,of,sz,rw,b,n)
 #define VOP_OPEN(vp, cr, rv)						\
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 162c6e57307a..3de2bfb2410f 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 pipe_inode_info *, struct file *, size_t, unsigned int);
-	ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned int);
+	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
+	ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
 };
 
 struct inode_operations {
@@ -1613,13 +1613,13 @@ extern void do_generic_mapping_read(struct address_space *mapping,
 				    loff_t *, read_descriptor_t *, read_actor_t);
 
 /* fs/splice.c */
-extern ssize_t generic_file_splice_read(struct file *,
+extern ssize_t generic_file_splice_read(struct file *, loff_t *,
 		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);
+		struct file *, loff_t *, size_t, unsigned int);
 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
-		struct file *out, size_t len, unsigned int flags);
-extern long do_splice_direct(struct file *in, struct file *out,
+		struct file *out, loff_t *, size_t len, unsigned int flags);
+extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
 		size_t len, unsigned int flags);
 
 extern void
-- 
cgit v1.2.1


From 70524490ee2ea1bbf6cee6c106597b3ac25a3fc2 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@suse.de>
Date: Tue, 11 Apr 2006 15:51:17 +0200
Subject: [PATCH] splice: add support for sys_tee()

Basically an in-kernel implementation of tee, which uses splice and the
pipe buffers as an intelligent way to pass data around by reference.

Where the user space tee consumes the input and produces a stdout and
file output, this syscall merely duplicates the data inside a pipe to
another pipe. No data is copied, the output just grabs a reference to the
input pipe data.

Signed-off-by: Jens Axboe <axboe@suse.de>
---
 arch/i386/kernel/syscall_table.S |   1 +
 arch/ia64/kernel/entry.S         |   1 +
 arch/powerpc/kernel/systbl.S     |   1 +
 fs/pipe.c                        |   7 ++
 fs/splice.c                      | 186 +++++++++++++++++++++++++++++++++++++++
 include/asm-i386/unistd.h        |   3 +-
 include/asm-ia64/unistd.h        |   3 +-
 include/asm-powerpc/unistd.h     |   3 +-
 include/asm-x86_64/unistd.h      |   4 +-
 include/linux/pipe_fs_i.h        |   1 +
 include/linux/syscalls.h         |   2 +
 11 files changed, 208 insertions(+), 4 deletions(-)

diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
index 4f58b9c0efe3..f48bef15b4f0 100644
--- a/arch/i386/kernel/syscall_table.S
+++ b/arch/i386/kernel/syscall_table.S
@@ -314,3 +314,4 @@ ENTRY(sys_call_table)
 	.long sys_get_robust_list
 	.long sys_splice
 	.long sys_sync_file_range
+	.long sys_tee			/* 315 */
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index 6e16f6b35bd3..e30798811216 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1609,5 +1609,6 @@ sys_call_table:
 	data8 sys_set_robust_list
 	data8 sys_get_robust_list
 	data8 sys_sync_file_range		// 1300
+	data8 sys_tee
 
 	.org sys_call_table + 8*NR_syscalls	// guard against failures to increase NR_syscalls
diff --git a/arch/powerpc/kernel/systbl.S b/arch/powerpc/kernel/systbl.S
index 1424eab450ee..a14c96403840 100644
--- a/arch/powerpc/kernel/systbl.S
+++ b/arch/powerpc/kernel/systbl.S
@@ -323,3 +323,4 @@ COMPAT_SYS(pselect6)
 COMPAT_SYS(ppoll)
 SYSCALL(unshare)
 SYSCALL(splice)
+SYSCALL(tee)
diff --git a/fs/pipe.c b/fs/pipe.c
index e984beb93a0e..7fefb10db8d9 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -131,12 +131,19 @@ static int anon_pipe_buf_steal(struct pipe_inode_info *pipe,
 	return 0;
 }
 
+static void anon_pipe_buf_get(struct pipe_inode_info *info,
+			      struct pipe_buffer *buf)
+{
+	page_cache_get(buf->page);
+}
+
 static struct pipe_buf_operations anon_pipe_buf_ops = {
 	.can_merge = 1,
 	.map = anon_pipe_buf_map,
 	.unmap = anon_pipe_buf_unmap,
 	.release = anon_pipe_buf_release,
 	.steal = anon_pipe_buf_steal,
+	.get = anon_pipe_buf_get,
 };
 
 static ssize_t
diff --git a/fs/splice.c b/fs/splice.c
index 5d3eda64703b..8d57e89924a6 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -125,12 +125,19 @@ static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
 	kunmap(buf->page);
 }
 
+static void page_cache_pipe_buf_get(struct pipe_inode_info *info,
+				    struct pipe_buffer *buf)
+{
+	page_cache_get(buf->page);
+}
+
 static struct pipe_buf_operations page_cache_pipe_buf_ops = {
 	.can_merge = 0,
 	.map = page_cache_pipe_buf_map,
 	.unmap = page_cache_pipe_buf_unmap,
 	.release = page_cache_pipe_buf_release,
 	.steal = page_cache_pipe_buf_steal,
+	.get = page_cache_pipe_buf_get,
 };
 
 /*
@@ -963,3 +970,182 @@ asmlinkage long sys_splice(int fd_in, loff_t __user *off_in,
 
 	return error;
 }
+
+/*
+ * Link contents of ipipe to opipe.
+ */
+static int link_pipe(struct pipe_inode_info *ipipe,
+		     struct pipe_inode_info *opipe,
+		     size_t len, unsigned int flags)
+{
+	struct pipe_buffer *ibuf, *obuf;
+	int ret = 0, do_wakeup = 0, i;
+
+	/*
+	 * Potential ABBA deadlock, work around it by ordering lock
+	 * grabbing by inode address. Otherwise two different processes
+	 * could deadlock (one doing tee from A -> B, the other from B -> A).
+	 */
+	if (ipipe->inode < opipe->inode) {
+		mutex_lock(&ipipe->inode->i_mutex);
+		mutex_lock(&opipe->inode->i_mutex);
+	} else {
+		mutex_lock(&opipe->inode->i_mutex);
+		mutex_lock(&ipipe->inode->i_mutex);
+	}
+
+	for (i = 0;; i++) {
+		if (!opipe->readers) {
+			send_sig(SIGPIPE, current, 0);
+			if (!ret)
+				ret = -EPIPE;
+			break;
+		}
+		if (ipipe->nrbufs - i) {
+			ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1));
+
+			/*
+			 * If we have room, fill this buffer
+			 */
+			if (opipe->nrbufs < PIPE_BUFFERS) {
+				int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1);
+
+				/*
+				 * Get a reference to this pipe buffer,
+				 * so we can copy the contents over.
+				 */
+				ibuf->ops->get(ipipe, ibuf);
+
+				obuf = opipe->bufs + nbuf;
+				*obuf = *ibuf;
+
+				if (obuf->len > len)
+					obuf->len = len;
+
+				opipe->nrbufs++;
+				do_wakeup = 1;
+				ret += obuf->len;
+				len -= obuf->len;
+
+				if (!len)
+					break;
+				if (opipe->nrbufs < PIPE_BUFFERS)
+					continue;
+			}
+
+			/*
+			 * We have input available, but no output room.
+			 * If we already copied data, return that.
+			 */
+			if (flags & SPLICE_F_NONBLOCK) {
+				if (!ret)
+					ret = -EAGAIN;
+				break;
+			}
+			if (signal_pending(current)) {
+				if (!ret)
+					ret = -ERESTARTSYS;
+				break;
+			}
+			if (do_wakeup) {
+				smp_mb();
+				if (waitqueue_active(&opipe->wait))
+					wake_up_interruptible(&opipe->wait);
+				kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN);
+				do_wakeup = 0;
+			}
+
+			opipe->waiting_writers++;
+			pipe_wait(opipe);
+			opipe->waiting_writers--;
+			continue;
+		}
+
+		/*
+		 * No input buffers, do the usual checks for available
+		 * writers and blocking and wait if necessary
+		 */
+		if (!ipipe->writers)
+			break;
+		if (!ipipe->waiting_writers) {
+			if (ret)
+				break;
+		}
+		if (flags & SPLICE_F_NONBLOCK) {
+			if (!ret)
+				ret = -EAGAIN;
+			break;
+		}
+		if (signal_pending(current)) {
+			if (!ret)
+				ret = -ERESTARTSYS;
+			break;
+		}
+
+		if (waitqueue_active(&ipipe->wait))
+			wake_up_interruptible_sync(&ipipe->wait);
+		kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT);
+
+		pipe_wait(ipipe);
+	}
+
+	mutex_unlock(&ipipe->inode->i_mutex);
+	mutex_unlock(&opipe->inode->i_mutex);
+
+	if (do_wakeup) {
+		smp_mb();
+		if (waitqueue_active(&opipe->wait))
+			wake_up_interruptible(&opipe->wait);
+		kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN);
+	}
+
+	return ret;
+}
+
+/*
+ * This is a tee(1) implementation that works on pipes. It doesn't copy
+ * any data, it simply references the 'in' pages on the 'out' pipe.
+ * The 'flags' used are the SPLICE_F_* variants, currently the only
+ * applicable one is SPLICE_F_NONBLOCK.
+ */
+static long do_tee(struct file *in, struct file *out, size_t len,
+		   unsigned int flags)
+{
+	struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe;
+	struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe;
+
+	/*
+	 * Link ipipe to the two output pipes, consuming as we go along.
+	 */
+	if (ipipe && opipe)
+		return link_pipe(ipipe, opipe, len, flags);
+
+	return -EINVAL;
+}
+
+asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags)
+{
+	struct file *in;
+	int error, fput_in;
+
+	if (unlikely(!len))
+		return 0;
+
+	error = -EBADF;
+	in = fget_light(fdin, &fput_in);
+	if (in) {
+		if (in->f_mode & FMODE_READ) {
+			int fput_out;
+			struct file *out = fget_light(fdout, &fput_out);
+
+			if (out) {
+				if (out->f_mode & FMODE_WRITE)
+					error = do_tee(in, out, len, flags);
+				fput_light(out, fput_out);
+			}
+		}
+ 		fput_light(in, fput_in);
+ 	}
+
+	return error;
+}
diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index 6a8dd83c350f..d81d6cfc1bb4 100644
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -320,8 +320,9 @@
 #define __NR_get_robust_list	312
 #define __NR_splice		313
 #define __NR_sync_file_range	314
+#define __NR_tee		315
 
-#define NR_syscalls 315
+#define NR_syscalls 316
 
 /*
  * user-visible error numbers are in the range -1 - -128: see
diff --git a/include/asm-ia64/unistd.h b/include/asm-ia64/unistd.h
index 1c749acca021..a40ebec6aeeb 100644
--- a/include/asm-ia64/unistd.h
+++ b/include/asm-ia64/unistd.h
@@ -289,12 +289,13 @@
 #define __NR_set_robust_list		1298
 #define __NR_get_robust_list		1299
 #define __NR_sync_file_range		1300
+#define __NR_tee			1301
 
 #ifdef __KERNEL__
 
 #include <linux/config.h>
 
-#define NR_syscalls			277 /* length of syscall table */
+#define NR_syscalls			278 /* length of syscall table */
 
 #define __ARCH_WANT_SYS_RT_SIGACTION
 
diff --git a/include/asm-powerpc/unistd.h b/include/asm-powerpc/unistd.h
index 536ba0873052..c612f1a62772 100644
--- a/include/asm-powerpc/unistd.h
+++ b/include/asm-powerpc/unistd.h
@@ -302,8 +302,9 @@
 #define __NR_ppoll		281
 #define __NR_unshare		282
 #define __NR_splice		283
+#define __NR_tee		284
 
-#define __NR_syscalls		284
+#define __NR_syscalls		285
 
 #ifdef __KERNEL__
 #define __NR__exit __NR_exit
diff --git a/include/asm-x86_64/unistd.h b/include/asm-x86_64/unistd.h
index f21ff2c1e960..d86494e23b63 100644
--- a/include/asm-x86_64/unistd.h
+++ b/include/asm-x86_64/unistd.h
@@ -611,8 +611,10 @@ __SYSCALL(__NR_set_robust_list, sys_set_robust_list)
 __SYSCALL(__NR_get_robust_list, sys_get_robust_list)
 #define __NR_splice		275
 __SYSCALL(__NR_splice, sys_splice)
+#define __NR_tee		276
+__SYSCALL(__NR_tee, sys_tee)
 
-#define __NR_syscall_max __NR_splice
+#define __NR_syscall_max __NR_tee
 
 #ifndef __NO_STUBS
 
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 123a7c24bc72..ef7f33c0be19 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -21,6 +21,7 @@ struct pipe_buf_operations {
 	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 *);
+	void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
 };
 
 struct pipe_inode_info {
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index f001bad28d9a..d3ebc0e68b2b 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -574,6 +574,8 @@ asmlinkage long sys_splice(int fd_in, loff_t __user *off_in,
 			   int fd_out, loff_t __user *off_out,
 			   size_t len, unsigned int flags);
 
+asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags);
+
 asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
 					unsigned int flags);
 
-- 
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