Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

[thirdparty/kernel/stable.git] / mm / gup.c

diff --git a/mm/gup.c b/mm/gup.c
index f173fcbaf1b2c9ab40dd65a6b2f3517aa7790ab5..ddde097cf9e4106bc02ea55538926f44ed8e587c 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1042,10 +1042,6 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
                        BUG_ON(ret >= nr_pages);
                }
 
-               if (!pages)
-                       /* If it's a prefault don't insist harder */
-                       return ret;
-
                if (ret > 0) {
                        nr_pages -= ret;
                        pages_done += ret;
@@ -1061,8 +1057,12 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
                                pages_done = ret;
                        break;
                }
-               /* VM_FAULT_RETRY triggered, so seek to the faulting offset */
-               pages += ret;
+               /*
+                * VM_FAULT_RETRY triggered, so seek to the faulting offset.
+                * For the prefault case (!pages) we only update counts.
+                */
+               if (likely(pages))
+                       pages += ret;
                start += ret << PAGE_SHIFT;
 
                /*
@@ -1085,7 +1085,8 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
                pages_done++;
                if (!nr_pages)
                        break;
-               pages++;
+               if (likely(pages))
+                       pages++;
                start += PAGE_SIZE;
        }
        if (lock_dropped && *locked) {