splice: don't pass the address of ->f_pos to methods

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 18 insertions, 13 deletions

diff --git a/fs/splice.c b/fs/splice.c
index e6b2559..9eca476 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1274,7 +1274,7 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
 {
 	struct file *file = sd->u.file;
 
-	return do_splice_from(pipe, file, &file->f_pos, sd->total_len,
+	return do_splice_from(pipe, file, sd->opos, sd->total_len,
 			      sd->flags);
 }
 
@@ -1294,7 +1294,7 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
  *
  */
 long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
-		      size_t len, unsigned int flags)
+		      loff_t *opos, size_t len, unsigned int flags)
 {
 	struct splice_desc sd = {
 		.len		= len,
@@ -1302,6 +1302,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
 		.flags		= flags,
 		.pos		= *ppos,
 		.u.file		= out,
+		.opos		= opos,
 	};
 	long ret;
 
@@ -1325,7 +1326,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 {
 	struct pipe_inode_info *ipipe;
 	struct pipe_inode_info *opipe;
-	loff_t offset, *off;
+	loff_t offset;
 	long ret;
 
 	ipipe = get_pipe_info(in);
@@ -1356,13 +1357,15 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 				return -EINVAL;
 			if (copy_from_user(&offset, off_out, sizeof(loff_t)))
 				return -EFAULT;
-			off = &offset;
-		} else
-			off = &out->f_pos;
+		} else {
+			offset = out->f_pos;
+		}
 
-		ret = do_splice_from(ipipe, out, off, len, flags);
+		ret = do_splice_from(ipipe, out, &offset, len, flags);
 
-		if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
+		if (!off_out)
+			out->f_pos = offset;
+		else if (copy_to_user(off_out, &offset, sizeof(loff_t)))
 			ret = -EFAULT;
 
 		return ret;
@@ -1376,13 +1379,15 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 				return -EINVAL;
 			if (copy_from_user(&offset, off_in, sizeof(loff_t)))
 				return -EFAULT;
-			off = &offset;
-		} else
-			off = &in->f_pos;
+		} else {
+			offset = in->f_pos;
+		}
 
-		ret = do_splice_to(in, off, opipe, len, flags);
+		ret = do_splice_to(in, &offset, opipe, len, flags);
 
-		if (off_in && copy_to_user(off_in, off, sizeof(loff_t)))
+		if (!off_in)
+			in->f_pos = offset;
+		else if (copy_to_user(off_in, &offset, sizeof(loff_t)))
 			ret = -EFAULT;
 
 		return ret;