mm, memory_hotplug: __offline_pages fix wrong locking

Jan has noticed that we do double unlock on some failure paths when
offlining a page range.  This is indeed the case when
test_pages_in_a_zone respp.  start_isolate_page_range fail.  This was an
omission when forward porting the debugging patch from an older kernel.

Fix the issue by dropping mem_hotplug_done from the failure condition
and keeping the single unlock in the catch all failure path.

Link: http://lkml.kernel.org/r/20190115120307.22768-1-mhocko@kernel.org
Fixes: 7960509329c2 ("mm, memory_hotplug: print reason for the offlining failure")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Tested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a0130633a6e1b3326126697480ec66993493e907..124e794867c564c693e80a2b5827aebe3d3643d3 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1570,7 +1570,6 @@ static int __ref __offline_pages(unsigned long start_pfn,
           we assume this for now. .*/
        if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
                                  &valid_end)) {
-               mem_hotplug_done();
                ret = -EINVAL;
                reason = "multizone range";
                goto failed_removal;
@@ -1585,7 +1584,6 @@ static int __ref __offline_pages(unsigned long start_pfn,
                                       MIGRATE_MOVABLE,
                                       SKIP_HWPOISON | REPORT_FAILURE);
        if (ret) {
-               mem_hotplug_done();
                reason = "failure to isolate range";
                goto failed_removal;
        }