[PATCH v2 1/6] mm/memory_hotplug: Exit early in __remove_pages() on BUGs

From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, David Hildenbrand <david@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Oscar Salvador <osalvador@suse.de>,
	Michal Hocko <mhocko@suse.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Wei Yang <richardw.yang@linux.intel.com>
Subject: [PATCH v2 1/6] mm/memory_hotplug: Exit early in __remove_pages() on BUGs
Date: Mon, 26 Aug 2019 12:10:07 +0200	[thread overview]
Message-ID: <20190826101012.10575-2-david@redhat.com> (raw)
In-Reply-To: <20190826101012.10575-1-david@redhat.com>

The error path should never happen in practice (unless bringing up a new
device driver, or on BUGs). However, it's clearer to not touch anything
in case we are going to return right away. Move the check/return.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/memory_hotplug.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 32a5386758ce..71779b7b14df 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -542,13 +542,13 @@ void __remove_pages(struct zone *zone, unsigned long pfn,
 	unsigned long map_offset = 0;
 	unsigned long nr, start_sec, end_sec;
 
+	if (check_pfn_span(pfn, nr_pages, "remove"))
+		return;
+
 	map_offset = vmem_altmap_offset(altmap);
 
 	clear_zone_contiguous(zone);
 
-	if (check_pfn_span(pfn, nr_pages, "remove"))
-		return;
-
 	start_sec = pfn_to_section_nr(pfn);
 	end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
 	for (nr = start_sec; nr <= end_sec; nr++) {
-- 
2.21.0

