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

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

1 files changed, 16 insertions, 8 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 03430008704e..2cefa417be34 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1064,6 +1064,7 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         struct fd in, out;
         struct inode *in_inode, *out_inode;
         loff_t pos;
+        loff_t out_pos;
         ssize_t retval;
         int fl;
 
@@ -1077,12 +1078,14 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         if (!(in.file->f_mode & FMODE_READ))
                 goto fput_in;
         retval = -ESPIPE;
-        if (!ppos)
-                ppos = &in.file->f_pos;
-        else
+        if (!ppos) {
+                pos = in.file->f_pos;
+        } else {
+                pos = *ppos;
                 if (!(in.file->f_mode & FMODE_PREAD))
                         goto fput_in;
-        retval = rw_verify_area(READ, in.file, ppos, count);
+        }
+        retval = rw_verify_area(READ, in.file, &pos, count);
         if (retval < 0)
                 goto fput_in;
         count = retval;
@@ -1099,7 +1102,8 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         retval = -EINVAL;
         in_inode = file_inode(in.file);
         out_inode = file_inode(out.file);
-        retval = rw_verify_area(WRITE, out.file, &out.file->f_pos, count);
+        out_pos = out.file->f_pos;
+        retval = rw_verify_area(WRITE, out.file, &out_pos, count);
         if (retval < 0)
                 goto fput_out;
         count = retval;
@@ -1107,7 +1111,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         if (!max)
                 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
 
-        pos = *ppos;
         if (unlikely(pos + count > max)) {
                 retval = -EOVERFLOW;
                 if (pos >= max)
@@ -1126,18 +1129,23 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         if (in.file->f_flags & O_NONBLOCK)
                 fl = SPLICE_F_NONBLOCK;
 #endif
-        retval = do_splice_direct(in.file, ppos, out.file, count, fl);
+        retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
 
         if (retval > 0) {
                 add_rchar(current, retval);
                 add_wchar(current, retval);
                 fsnotify_access(in.file);
                 fsnotify_modify(out.file);
+                out.file->f_pos = out_pos;
+                if (ppos)
+                        *ppos = pos;
+                else
+                        in.file->f_pos = pos;
         }
 
         inc_syscr(current);
         inc_syscw(current);
-        if (*ppos > max)
+        if (pos > max)
                 retval = -EOVERFLOW;
 
 fput_out: