All callers of arch_remove_memory() ignore errors. And we should really
try to remove any errors from the memory removal path.
No more errors are reported from __remove_pages(). BUG() in s390x code
in case arch_remove_memory() is triggered. We may implement that properly
later. WARN in case powerpc code failed to remove the section mapping,
which is better than ignoring the error completely right now.

Cc: Tony Luck <tony.l...@intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Martin Schwidefsky <schwidef...@de.ibm.com>
Cc: Heiko Carstens <heiko.carst...@de.ibm.com>
Cc: Yoshinori Sato <ys...@users.sourceforge.jp>
Cc: Rich Felker <dal...@libc.org>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: x...@kernel.org
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Michal Hocko <mho...@suse.com>
Cc: Mike Rapoport <r...@linux.ibm.com>
Cc: Oscar Salvador <osalva...@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com>
Cc: Christophe Leroy <christophe.le...@c-s.fr>
Cc: Stefan Agner <ste...@agner.ch>
Cc: Nicholas Piggin <npig...@gmail.com>
Cc: Pavel Tatashin <pasha.tatas...@soleen.com>
Cc: Vasily Gorbik <g...@linux.ibm.com>
Cc: Arun KS <aru...@codeaurora.org>
Cc: Geert Uytterhoeven <ge...@linux-m68k.org>
Cc: Masahiro Yamada <yamada.masah...@socionext.com>
Cc: Rob Herring <r...@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo....@lge.com>
Cc: Wei Yang <richard.weiy...@gmail.com>
Cc: Qian Cai <c...@lca.pw>
Cc: Mathieu Malaterre <ma...@debian.org>
Cc: linux-i...@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux...@vger.kernel.org
Cc: linux-s...@vger.kernel.org
Signed-off-by: David Hildenbrand <da...@redhat.com>
---
 arch/ia64/mm/init.c            | 11 +++--------
 arch/powerpc/mm/mem.c          | 11 ++++-------
 arch/s390/mm/init.c            |  5 +++--
 arch/sh/mm/init.c              | 11 +++--------
 arch/x86/mm/init_32.c          |  5 +++--
 arch/x86/mm/init_64.c          | 10 +++-------
 include/linux/memory_hotplug.h |  8 ++++----
 mm/memory_hotplug.c            |  5 ++---
 8 files changed, 25 insertions(+), 41 deletions(-)

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 379eb1f9adc9..d28e29103bdb 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -682,20 +682,15 @@ int arch_add_memory(int nid, u64 start, u64 size,
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(int nid, u64 start, u64 size, struct vmem_altmap 
*altmap)
+void arch_remove_memory(int nid, u64 start, u64 size,
+                       struct vmem_altmap *altmap)
 {
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;
        struct zone *zone;
-       int ret;
 
        zone = page_zone(pfn_to_page(start_pfn));
-       ret = __remove_pages(zone, start_pfn, nr_pages, altmap);
-       if (ret)
-               pr_warn("%s: Problem encountered in __remove_pages() as"
-                       " ret=%d\n", __func__,  ret);
-
-       return ret;
+       __remove_pages(zone, start_pfn, nr_pages, altmap);
 }
 #endif
 #endif
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 76deaa8525db..cc9425fb9056 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -131,8 +131,8 @@ int __meminit arch_add_memory(int nid, u64 start, u64 size,
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-int __meminit arch_remove_memory(int nid, u64 start, u64 size,
-                                       struct vmem_altmap *altmap)
+void __meminit arch_remove_memory(int nid, u64 start, u64 size,
+                                 struct vmem_altmap *altmap)
 {
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;
@@ -147,14 +147,13 @@ int __meminit arch_remove_memory(int nid, u64 start, u64 
size,
        if (altmap)
                page += vmem_altmap_offset(altmap);
 
-       ret = __remove_pages(page_zone(page), start_pfn, nr_pages, altmap);
-       if (ret)
-               return ret;
+       __remove_pages(page_zone(page), start_pfn, nr_pages, altmap);
 
        /* Remove htab bolted mappings for this section of memory */
        start = (unsigned long)__va(start);
        flush_inval_dcache_range(start, start + size);
        ret = remove_section_mapping(start, start + size);
+       WARN_ON_ONCE(ret);
 
        /* Ensure all vmalloc mappings are flushed in case they also
         * hit that section of memory
@@ -162,8 +161,6 @@ int __meminit arch_remove_memory(int nid, u64 start, u64 
size,
        vm_unmap_aliases();
 
        resize_hpt_for_hotplug(memblock_phys_mem_size());
-
-       return ret;
 }
 #endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index f5db961ad792..31b1071315d7 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -234,14 +234,15 @@ int arch_add_memory(int nid, u64 start, u64 size,
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(int nid, u64 start, u64 size, struct vmem_altmap 
*altmap)
+void arch_remove_memory(int nid, u64 start, u64 size,
+                       struct vmem_altmap *altmap)
 {
        /*
         * There is no hardware or firmware interface which could trigger a
         * hot memory remove on s390. So there is nothing that needs to be
         * implemented.
         */
-       return -EBUSY;
+       BUG();
 }
 #endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 168d3a6b9358..5aeb4d7099a1 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c
@@ -429,20 +429,15 @@ EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 #endif
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(int nid, u64 start, u64 size, struct vmem_altmap 
*altmap)
+void arch_remove_memory(int nid, u64 start, u64 size,
+                       struct vmem_altmap *altmap)
 {
        unsigned long start_pfn = PFN_DOWN(start);
        unsigned long nr_pages = size >> PAGE_SHIFT;
        struct zone *zone;
-       int ret;
 
        zone = page_zone(pfn_to_page(start_pfn));
-       ret = __remove_pages(zone, start_pfn, nr_pages, altmap);
-       if (unlikely(ret))
-               pr_warn("%s: Failed, __remove_pages() == %d\n", __func__,
-                       ret);
-
-       return ret;
+       __remove_pages(zone, start_pfn, nr_pages, altmap);
 }
 #endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 755dbed85531..075e568098f2 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -860,14 +860,15 @@ int arch_add_memory(int nid, u64 start, u64 size,
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(int nid, u64 start, u64 size, struct vmem_altmap 
*altmap)
+void arch_remove_memory(int nid, u64 start, u64 size,
+                       struct vmem_altmap *altmap)
 {
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;
        struct zone *zone;
 
        zone = page_zone(pfn_to_page(start_pfn));
-       return __remove_pages(zone, start_pfn, nr_pages, altmap);
+       __remove_pages(zone, start_pfn, nr_pages, altmap);
 }
 #endif
 #endif
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index db42c11b48fb..20d14254b686 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1141,24 +1141,20 @@ kernel_physical_mapping_remove(unsigned long start, 
unsigned long end)
        remove_pagetable(start, end, true, NULL);
 }
 
-int __ref arch_remove_memory(int nid, u64 start, u64 size,
-                               struct vmem_altmap *altmap)
+void __ref arch_remove_memory(int nid, u64 start, u64 size,
+                             struct vmem_altmap *altmap)
 {
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;
        struct page *page = pfn_to_page(start_pfn);
        struct zone *zone;
-       int ret;
 
        /* With altmap the first mapped page is offset from @start */
        if (altmap)
                page += vmem_altmap_offset(altmap);
        zone = page_zone(page);
-       ret = __remove_pages(zone, start_pfn, nr_pages, altmap);
-       WARN_ON_ONCE(ret);
+       __remove_pages(zone, start_pfn, nr_pages, altmap);
        kernel_physical_mapping_remove(start, start + size);
-
-       return ret;
 }
 #endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index d0a145ffa4fe..9d0efac902ec 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -112,10 +112,10 @@ static inline bool movable_node_is_enabled(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-extern int arch_remove_memory(int nid, u64 start, u64 size,
-                               struct vmem_altmap *altmap);
-extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
-       unsigned long nr_pages, struct vmem_altmap *altmap);
+extern void arch_remove_memory(int nid, u64 start, u64 size,
+                              struct vmem_altmap *altmap);
+extern void __remove_pages(struct zone *zone, unsigned long start_pfn,
+                          unsigned long nr_pages, struct vmem_altmap *altmap);
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
 /*
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 17a60281c36f..52fef4a81e4c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -548,8 +548,8 @@ static void __remove_section(struct zone *zone, struct 
mem_section *ms,
  * sure that pages are marked reserved and zones are adjust properly by
  * calling offline_pages().
  */
-int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
-                unsigned long nr_pages, struct vmem_altmap *altmap)
+void __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
+                   unsigned long nr_pages, struct vmem_altmap *altmap)
 {
        unsigned long i;
        unsigned long map_offset = 0;
@@ -580,7 +580,6 @@ int __remove_pages(struct zone *zone, unsigned long 
phys_start_pfn,
        }
 
        set_zone_contiguous(zone);
-       return 0;
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
-- 
2.17.2

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