mm/page_isolation: cleanup set_migratetype_isolate()

Let's clean it up a bit, simplifying the exit paths.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/20200816125333.7434-5-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index dfc55fa..aa94afb 100644 (file)
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -17,12 +17,9 @@
 
 static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags)
 {
-       struct page *unmovable = NULL;
-       struct zone *zone;
+       struct zone *zone = page_zone(page);
+       struct page *unmovable;
        unsigned long flags;
-       int ret = -EBUSY;
-
-       zone = page_zone(page);
 
        spin_lock_irqsave(&zone->lock, flags);
 
@@ -51,13 +48,13 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
                                                                        NULL);
 
                __mod_zone_freepage_state(zone, -nr_pages, mt);
-               ret = 0;
+               spin_unlock_irqrestore(&zone->lock, flags);
+               drain_all_pages(zone);
+               return 0;
        }
 
        spin_unlock_irqrestore(&zone->lock, flags);
-       if (!ret) {
-               drain_all_pages(zone);
-       } else if ((isol_flags & REPORT_FAILURE) && unmovable) {
+       if (isol_flags & REPORT_FAILURE) {
                /*
                 * printk() with zone->lock held will likely trigger a
                 * lockdep splat, so defer it here.
@@ -65,7 +62,7 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
                dump_page(unmovable, "unmovable page");
        }
 
-       return ret;
+       return -EBUSY;
 }
 
 static void unset_migratetype_isolate(struct page *page, unsigned migratetype)