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-rw-r--r--mm/gup.c24
1 files changed, 16 insertions, 8 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 83d480e9b05f..f411bab037f5 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1449,25 +1449,31 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk,
struct vm_area_struct **vmas,
unsigned int gup_flags)
{
- long i;
+ unsigned long i;
+ unsigned long step;
bool drain_allow = true;
bool migrate_allow = true;
LIST_HEAD(cma_page_list);
check_again:
- for (i = 0; i < nr_pages; i++) {
+ for (i = 0; i < nr_pages;) {
+
+ struct page *head = compound_head(pages[i]);
+
+ /*
+ * gup may start from a tail page. Advance step by the left
+ * part.
+ */
+ step = (1 << compound_order(head)) - (pages[i] - head);
/*
* If we get a page from the CMA zone, since we are going to
* be pinning these entries, we might as well move them out
* of the CMA zone if possible.
*/
- if (is_migrate_cma_page(pages[i])) {
-
- struct page *head = compound_head(pages[i]);
-
- if (PageHuge(head)) {
+ if (is_migrate_cma_page(head)) {
+ if (PageHuge(head))
isolate_huge_page(head, &cma_page_list);
- } else {
+ else {
if (!PageLRU(head) && drain_allow) {
lru_add_drain_all();
drain_allow = false;
@@ -1482,6 +1488,8 @@ check_again:
}
}
}
+
+ i += step;
}
if (!list_empty(&cma_page_list)) {