mm/memory_hotplug: make unregister_memory_section() never fail

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/20190409100148.24703-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 0c9e22ffa47af62328c04c6b0e14fccb2dbe5432..f180427e48f4e59341795c3090d51d84a5f83dc8 100644 (file)
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -734,15 +734,18 @@ 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);
 
        /*
@@ -763,15 +766,6 @@ 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 a6ddefc60517899167b55b53b0007ba3e3b9ed80..e1dc1bb2b787756d833266697161edfb69ceb7cb 100644 (file)
--- 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 65f166ec2e4c8f78b3eedce045b224837cefef56..1f3707ab7a63189097d442deab7f1879ced11135 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -526,9 +526,7 @@ 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);