mm: describe mmap_sem rules for __lock_page_or_retry() and callers

[mirror_ubuntu-artful-kernel.git] / arch / x86 / mm / fault.c

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 1dbade870f90dd8b27140e10275df6d0610506be..a241946815131904498ae6ecd95d87c4e28bf2f9 100644 (file)
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1218,7 +1218,8 @@ good_area:
        /*
         * If for any reason at all we couldn't handle the fault,
         * make sure we exit gracefully rather than endlessly redo
-        * the fault:
+        * the fault.  Since we never set FAULT_FLAG_RETRY_NOWAIT, if
+        * we get VM_FAULT_RETRY back, the mmap_sem has been unlocked.
         */
        fault = handle_mm_fault(mm, vma, address, flags);