Merge branch 'linus' into smp/hotplug

Apply upstream changes to avoid conflicts with pending patches.

1 files changed, 9 insertions, 0 deletions

diff --git a/mm/readahead.c b/mm/readahead.c
index 65ec288dc057..c8a955b1297e 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/dax.h>
 #include <linux/gfp.h>
 #include <linux/export.h>
 #include <linux/blkdev.h>
@@ -544,6 +545,14 @@ do_readahead(struct address_space *mapping, struct file *filp,
         if (!mapping || !mapping->a_ops)
                 return -EINVAL;
 
+        /*
+         * Readahead doesn't make sense for DAX inodes, but we don't want it
+         * to report a failure either.  Instead, we just return success and
+         * don't do any work.
+         */
+        if (dax_mapping(mapping))
+                return 0;
+
         return force_page_cache_readahead(mapping, filp, index, nr);
 }