[for,4.19-stable,09/25] mm/memory_hotplug: make unregister_memory_section() never fail

Commit Message

David Hildenbrand Jan. 15, 2020, 3:33 p.m. UTC

commit cb7b3a3685b20d3b5900ff24b2cb96d002960189 upstream.

Failing while removing memory is mostly ignored and cannot really be
handled.  Let's treat errors in unregister_memory_section() in a nice way,
warning, but continuing.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: David Hildenbrand <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: "Rafael J. Wysocki" <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Andrew Banman <[e-mail]>
Cc: Mike Travis <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: Oscar Salvador <[e-mail]>
Cc: Michal Hocko <[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: 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: Heiko Carstens <[e-mail]>
Cc: "H. Peter Anvin" <[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: Nicholas Piggin <[e-mail]>
Cc: Oscar Salvador <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[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]>
---
 drivers/base/memory.c  | 16 +++++-----------
 include/linux/memory.h |  2 +-
 mm/memory_hotplug.c    |  4 +---
 3 files changed, 7 insertions(+), 15 deletions(-)

Patch

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 119b076eb5e2..5b9950d982dc 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -743,15 +743,18 @@  unregister_memory(struct memory_block *memory)
 {
 	BUG_ON(memory->dev.bus != &memory_subsys);
 
-	/* drop the ref. we got in remove_memory_section() */
+	/* drop the ref. we got via find_memory_block() */
 	put_device(&memory->dev);
 	device_unregister(&memory->dev);
 }
 
-static int remove_memory_section(struct mem_section *section)
+void unregister_memory_section(struct mem_section *section)
 {
 	struct memory_block *mem;
 
+	if (WARN_ON_ONCE(!present_section(section)))
+		return;
+
 	mutex_lock(&mem_sysfs_mutex);
 
 	/*
@@ -772,15 +775,6 @@  static int remove_memory_section(struct mem_section *section)
 
 out_unlock:
 	mutex_unlock(&mem_sysfs_mutex);
-	return 0;
-}
-
-int unregister_memory_section(struct mem_section *section)
-{
-	if (!present_section(section))
-		return -EINVAL;
-
-	return remove_memory_section(section);
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
diff --git a/include/linux/memory.h b/include/linux/memory.h
index a6ddefc60517..e1dc1bb2b787 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -113,7 +113,7 @@  extern int register_memory_isolate_notifier(struct notifier_block *nb);
 extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
 int hotplug_memory_register(int nid, struct mem_section *section);
 #ifdef CONFIG_MEMORY_HOTREMOVE
-extern int unregister_memory_section(struct mem_section *);
+extern void unregister_memory_section(struct mem_section *);
 #endif
 extern int memory_dev_init(void);
 extern int memory_notify(unsigned long val, void *v);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 418d589552b3..42c5bc371ffe 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -488,9 +488,7 @@  static int __remove_section(struct zone *zone, struct mem_section *ms,
 	if (!valid_section(ms))
 		return ret;
 
-	ret = unregister_memory_section(ms);
-	if (ret)
-		return ret;
+	unregister_memory_section(ms);
 
 	scn_nr = __section_nr(ms);
 	start_pfn = section_nr_to_pfn((unsigned long)scn_nr);