Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter updates from Al Viro:
 "Cleanups that sat in -next + -stable fodder that has just missed 4.11.

  There's more iov_iter work in my local tree, but I'd prefer to push
  the stuff that had been in -next first"

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  iov_iter: don't revert iov buffer if csum error
  generic_file_read_iter(): make use of iov_iter_revert()
  generic_file_direct_write(): make use of iov_iter_revert()
  orangefs: use iov_iter_revert()
  sctp: switch to copy_from_iter_full()
  net/9p: switch to copy_from_iter_full()
  switch memcpy_from_msg() to copy_from_iter_full()
  rds: make use of iov_iter_revert()

1 files changed, 7 insertions, 8 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index c5808b7a5fb1..dc59c5f35b37 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2035,7 +2035,6 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
         if (iocb->ki_flags & IOCB_DIRECT) {
                 struct address_space *mapping = file->f_mapping;
                 struct inode *inode = mapping->host;
-                struct iov_iter data = *iter;
                 loff_t size;
 
                 size = i_size_read(inode);
@@ -2046,11 +2045,12 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 
                 file_accessed(file);
 
-                retval = mapping->a_ops->direct_IO(iocb, &data);
+                retval = mapping->a_ops->direct_IO(iocb, iter);
                 if (retval >= 0) {
                         iocb->ki_pos += retval;
-                        iov_iter_advance(iter, retval);
+                        count -= retval;
                 }
+                iov_iter_revert(iter, iov_iter_count(iter) - count);
 
                 /*
                  * Btrfs can have a short DIO read if we encounter
@@ -2061,7 +2061,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
                  * the rest of the read.  Buffered reads will not work for
                  * DAX files, so don't bother trying.
                  */
-                if (retval < 0 || !iov_iter_count(iter) || iocb->ki_pos >= size ||
+                if (retval < 0 || !count || iocb->ki_pos >= size ||
                     IS_DAX(inode))
                         goto out;
         }
@@ -2706,7 +2706,6 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
         ssize_t         written;
         size_t          write_len;
         pgoff_t         end;
-        struct iov_iter data;
 
         write_len = iov_iter_count(from);
         end = (pos + write_len - 1) >> PAGE_SHIFT;
@@ -2735,8 +2734,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
                 }
         }
 
-        data = *from;
-        written = mapping->a_ops->direct_IO(iocb, &data);
+        written = mapping->a_ops->direct_IO(iocb, from);
 
         /*
          * Finally, try again to invalidate clean pages which might have been
@@ -2753,13 +2751,14 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 
         if (written > 0) {
                 pos += written;
-                iov_iter_advance(from, written);
+                write_len -= written;
                 if (pos > i_size_read(inode) && !S_ISBLK(inode->i_mode)) {
                         i_size_write(inode, pos);
                         mark_inode_dirty(inode);
                 }
                 iocb->ki_pos = pos;
         }
+        iov_iter_revert(from, write_len - iov_iter_count(from));
 out:
         return written;
 }