Patch "mm/memory_hotplug: make unregister_memory_section() never fail" has been added to the 4.19-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    mm/memory_hotplug: make unregister_memory_section() never fail

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mm-memory_hotplug-make-unregister_memory_section-never-fail.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From foo@baz Tue 28 Jan 2020 02:32:10 PM CET
From: David Hildenbrand <david@redhat.com>
Date: Tue, 28 Jan 2020 10:50:06 +0100
Subject: mm/memory_hotplug: make unregister_memory_section() never fail
To: stable@vger.kernel.org
Cc: linux-mm@kvack.org, Michal Hocko <mhocko@suse.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Andrew Morton <akpm@linux-foundation.org>, "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>, Baoquan He <bhe@redhat.com>, Dan Williams <dan.j.williams@intel.com>, Oscar Salvador <osalvador@suse.de>, Wei Yang <richard.weiyang@gmail.com>, David Hildenbrand <david@redhat.com>
Message-ID: <20200128095021.8076-10-david@redhat.com>

From: David Hildenbrand <david@redhat.com>

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/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>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/base/memory.c  |   16 +++++-----------
 include/linux/memory.h |    2 +-
 mm/memory_hotplug.c    |    4 +---
 3 files changed, 7 insertions(+), 15 deletions(-)

--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -743,15 +743,18 @@ unregister_memory(struct memory_block *m
 {
 	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
 
 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 */
 
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -113,7 +113,7 @@ extern int register_memory_isolate_notif
 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);
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -488,9 +488,7 @@ static int __remove_section(struct zone
 	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);


Patches currently in stable-queue which might be from david@redhat.com are

queue-4.19/mm-memory_hotplug-remove-memory-block-devices-before-arch_remove_memory.patch
queue-4.19/mm-hotplug-kill-is_dev_zone-usage-in-__remove_pages.patch
queue-4.19/mm-memory_hotplug-create-memory-block-devices-after-arch_add_memory.patch
queue-4.19/drivers-base-memory-pass-a-block_id-to-init_memory_block.patch
queue-4.19/drivers-base-memory.c-clean-up-relics-in-function-parameters.patch
queue-4.19/mm-memory_hotplug-update-a-comment-in-unregister_memory.patch
queue-4.19/mm-memory_hotplug-shrink-zones-when-offlining-memory.patch
queue-4.19/mm-memory_hotplug-make-unregister_memory_block_under_nodes-never-fail.patch
queue-4.19/mm-memunmap-don-t-access-uninitialized-memmap-in-memunmap_pages.patch
queue-4.19/mm-memory_hotplug-make-__remove_section-never-fail.patch
queue-4.19/mm-sparse-drop-pgdat_resize_lock-in-sparse_add-remove_one_section.patch
queue-4.19/mm-memory_hotplug-make-unregister_memory_section-never-fail.patch
queue-4.19/mm-memory_hotplug-release-memory-resource-after-arch_remove_memory.patch
queue-4.19/mm-memory_hotplug-add-nid-parameter-to-arch_remove_memory.patch
queue-4.19/powerpc-mm-fix-section-mismatch-warning.patch
queue-4.19/mm-memory_hotplug-allow-arch_remove_memory-without-config_memory_hotremove.patch
queue-4.19/mm-memory_hotplug-make-remove_memory-take-the-device_hotplug_lock.patch
queue-4.19/mm-memory_hotplug-make-__remove_pages-and-arch_remove_memory-never-fail.patch
queue-4.19/mm-memory_hotplug-fix-try_offline_node.patch
queue-4.19/mm-memory_hotplug-remove-zone-parameter-from-sparse_remove_one_section.patch
queue-4.19/drivers-base-memory.c-remove-an-unnecessary-check-on-nr_mem_sections.patch
queue-4.19/drivers-base-node.c-simplify-unregister_memory_block_under_nodes.patch
queue-4.19/s390x-mm-implement-arch_remove_memory.patch
queue-4.19/mm-sparse-pass-nid-instead-of-pgdat-to-sparse_add_one_section.patch