[RFC PATCH V2 8/9] orangefs: use attach/clear_page_private

[Guoqing Jiang]

Since the new pair function is introduced, we can call them to clean the
code in orangefs.

Cc: Mike Marshall <hub...@omnibond.com>
Cc: Martin Brandenburg <mar...@omnibond.com>
Cc: de...@lists.orangefs.org
Signed-off-by: Guoqing Jiang <guoqing.ji...@cloud.ionos.com>
---
RFC -> RFC V2
1. change the name of new functions to attach/clear_page_private.
2. avoid potential use-after-free as suggested by Dave Chinner.

 fs/orangefs/inode.c | 32 ++++++--------------------------
 1 file changed, 6 insertions(+), 26 deletions(-)

diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
index 12ae630fbed7..139c450aca68 100644
--- a/fs/orangefs/inode.c
+++ b/fs/orangefs/inode.c
@@ -62,12 +62,7 @@ static int orangefs_writepage_locked(struct page *page,
        } else {
                ret = 0;
        }
-       if (wr) {
-               kfree(wr);
-               set_page_private(page, 0);
-               ClearPagePrivate(page);
-               put_page(page);
-       }
+       kfree(clear_page_private(page));
        return ret;
 }
 
@@ -409,9 +404,7 @@ static int orangefs_write_begin(struct file *file,
        wr->len = len;
        wr->uid = current_fsuid();
        wr->gid = current_fsgid();
-       SetPagePrivate(page);
-       set_page_private(page, (unsigned long)wr);
-       get_page(page);
+       attach_page_private(page, wr);
 okay:
        return 0;
 }
@@ -459,18 +452,12 @@ static void orangefs_invalidatepage(struct page *page,
        wr = (struct orangefs_write_range *)page_private(page);
 
        if (offset == 0 && length == PAGE_SIZE) {
-               kfree((struct orangefs_write_range *)page_private(page));
-               set_page_private(page, 0);
-               ClearPagePrivate(page);
-               put_page(page);
+               kfree(clear_page_private(page));
                return;
        /* write range entirely within invalidate range (or equal) */
        } else if (page_offset(page) + offset <= wr->pos &&
            wr->pos + wr->len <= page_offset(page) + offset + length) {
-               kfree((struct orangefs_write_range *)page_private(page));
-               set_page_private(page, 0);
-               ClearPagePrivate(page);
-               put_page(page);
+               kfree(clear_page_private(page));
                /* XXX is this right? only caller in fs */
                cancel_dirty_page(page);
                return;
@@ -535,12 +522,7 @@ static int orangefs_releasepage(struct page *page, gfp_t 
foo)
 
 static void orangefs_freepage(struct page *page)
 {
-       if (PagePrivate(page)) {
-               kfree((struct orangefs_write_range *)page_private(page));
-               set_page_private(page, 0);
-               ClearPagePrivate(page);
-               put_page(page);
-       }
+       kfree(clear_page_private(page));
 }
 
 static int orangefs_launder_page(struct page *page)
@@ -740,9 +722,7 @@ vm_fault_t orangefs_page_mkwrite(struct vm_fault *vmf)
        wr->len = PAGE_SIZE;
        wr->uid = current_fsuid();
        wr->gid = current_fsgid();
-       SetPagePrivate(page);
-       set_page_private(page, (unsigned long)wr);
-       get_page(page);
+       attach_page_private(page, wr);
 okay:
 
        file_update_time(vmf->vma->vm_file);
-- 
2.17.1