[PATCH] add AOP_TRUNCATED_PAGE, prepend AOP_ to WRITEPAGE_ACTIVATE

readpage(), prepare_write(), and commit_write() callers are updated to
understand the special return code AOP_TRUNCATED_PAGE in the style of
writepage() and WRITEPAGE_ACTIVATE.  AOP_TRUNCATED_PAGE tells the caller that
the callee has unlocked the page and that the operation should be tried again
with a new page.  OCFS2 uses this to detect and work around a lock inversion in
its aop methods.  There should be no change in behaviour for methods that don't
return AOP_TRUNCATED_PAGE.

WRITEPAGE_ACTIVATE is also prepended with AOP_ for consistency and they are
made enums so that kerneldoc can be used to document their semantics.

Signed-off-by: Zach Brown <zach.brown@oracle.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index dc25565a61e9..d9fc277940da 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -855,7 +855,7 @@ unlock:
         swap_free(swap);
 redirty:
         set_page_dirty(page);
-        return WRITEPAGE_ACTIVATE;      /* Return with the page locked */
+        return AOP_WRITEPAGE_ACTIVATE;  /* Return with the page locked */
 }
 
 #ifdef CONFIG_NUMA