[for,4.19-stable,v2,10/24] mm/memory_hotplug: make __remove_section() never fail

Commit Message

David Hildenbrand Jan. 21, 2020, 6:01 p.m. UTC

commit 9d1d887d785b4fe0590bd3c5e71acaa3908044e2 upstream.

Let's just warn in case a section is not valid instead of failing to
remove somewhere in the middle of the process, returning an error that
will be mostly ignored by callers.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: David Hildenbrand <[e-mail]>
Reviewed-by: Oscar Salvador <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: Pavel Tatashin <[e-mail]>
Cc: Qian Cai <[e-mail]>
Cc: Wei Yang <[e-mail]>
Cc: Arun KS <[e-mail]>
Cc: Mathieu Malaterre <[e-mail]>
Cc: Andrew Banman <[e-mail]>
Cc: Andy Lutomirski <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: Christophe Leroy <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Fenghua Yu <[e-mail]>
Cc: Geert Uytterhoeven <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: "Kirill A. Shutemov" <[e-mail]>
Cc: Martin Schwidefsky <[e-mail]>
Cc: Masahiro Yamada <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Mike Rapoport <[e-mail]>
Cc: Mike Travis <[e-mail]>
Cc: Nicholas Piggin <[e-mail]>
Cc: Oscar Salvador <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: "Rafael J. Wysocki" <[e-mail]>
Cc: Rich Felker <[e-mail]>
Cc: Rob Herring <[e-mail]>
Cc: Stefan Agner <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: Vasily Gorbik <[e-mail]>
Cc: Yoshinori Sato <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>
Signed-off-by: David Hildenbrand <[e-mail]>
---
 mm/memory_hotplug.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

Patch

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 42c5bc371ffe..a9fcae50a33a 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -478,15 +478,15 @@  static void __remove_zone(struct zone *zone, unsigned long start_pfn)
 	pgdat_resize_unlock(zone->zone_pgdat, &flags);
 }
 
-static int __remove_section(struct zone *zone, struct mem_section *ms,
-		unsigned long map_offset, struct vmem_altmap *altmap)
+static void __remove_section(struct zone *zone, struct mem_section *ms,
+			     unsigned long map_offset,
+			     struct vmem_altmap *altmap)
 {
 	unsigned long start_pfn;
 	int scn_nr;
-	int ret = -EINVAL;
 
-	if (!valid_section(ms))
-		return ret;
+	if (WARN_ON_ONCE(!valid_section(ms)))
+		return;
 
 	unregister_memory_section(ms);
 
@@ -495,7 +495,6 @@  static int __remove_section(struct zone *zone, struct mem_section *ms,
 	__remove_zone(zone, start_pfn);
 
 	sparse_remove_one_section(zone, ms, map_offset, altmap);
-	return 0;
 }
 
 /**
@@ -515,7 +514,7 @@  int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 {
 	unsigned long i;
 	unsigned long map_offset = 0;
-	int sections_to_remove, ret = 0;
+	int sections_to_remove;
 
 	/* In the ZONE_DEVICE case device driver owns the memory region */
 	if (is_dev_zone(zone)) {
@@ -536,16 +535,13 @@  int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 		unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
 
 		cond_resched();
-		ret = __remove_section(zone, __pfn_to_section(pfn), map_offset,
-				altmap);
+		__remove_section(zone, __pfn_to_section(pfn), map_offset,
+				 altmap);
 		map_offset = 0;
-		if (ret)
-			break;
 	}
 
 	set_zone_contiguous(zone);
-
-	return ret;
+	return 0;
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */