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-rw-r--r--mm/gup.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/mm/gup.c b/mm/gup.c
index f173fcbaf1b2..ddde097cf9e4 100644
--- 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) {