filemap: add a comment about FAULT_FLAG_RETRY_NOWAIT behavior

[linux-2.6-microblaze.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index 2815cb7..d78f577 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2428,6 +2428,11 @@ static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page,
        if (trylock_page(page))
                return 1;
 
+       /*
+        * NOTE! This will make us return with VM_FAULT_RETRY, but with
+        * the mmap_sem still held. That's how FAULT_FLAG_RETRY_NOWAIT
+        * is supposed to work. We have way too many special cases..
+        */
        if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)
                return 0;