mm/memory_hotplug: make __remove_pages() and arch_remove_memory() never fail

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.

Link: http://lkml.kernel.org/r/20190409100148.24703-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 379eb1f9adc91fbf6f8cd56acadeef2c8f439e52..d28e29103bdbab519293b97a455286edac33d6e7 100644 (file)
--- 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 de5c591a550d46b68446ad6eda798da84380bd70..e885fe2aafcc7bd7717baff2b31b14368c082e93 100644 (file)
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -131,7 +131,7 @@ int __ref arch_add_memory(int nid, u64 start, u64 size,
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-int __ref arch_remove_memory(int nid, u64 start, u64 size,
+void __ref arch_remove_memory(int nid, u64 start, u64 size,
                             struct vmem_altmap *altmap)
 {
        unsigned long start_pfn = start >> PAGE_SHIFT;
@@ -147,14 +147,13 @@ int __ref 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
@@ -163,8 +162,6 @@ int __ref arch_remove_memory(int nid, u64 start, u64 size,
 
        if (resize_hpt_for_hotplug(memblock_phys_mem_size()) == -ENOSPC)
                pr_warn("Hash collision while resizing HPT\n");
-
-       return ret;
 }
 #endif
 #endif /* CONFIG_MEMORY_HOTPLUG */

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 06bd05137a0075fc49c0578bf809448aa6164480..14d1eae9fe43c9e553d8aa7fa656a92d312d0ea0 100644 (file)
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -237,14 +237,15 @@ 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 d3cd07bd2dc1cd8abf912d65666bbd00cf70bcbe..b95e343e3c9de6a847010fc98fe7948428bdcbec 100644 (file)
--- 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 755dbed855313bd987b70d6e5e7077e745088c32..075e568098f25d86910033b994cb9710b5f1a56f 100644 (file)
--- 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 db42c11b48fb986417c81636e013de937cf99828..20d14254b6869263a00beb160694ff4f36f41628 100644 (file)
--- 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 b24aca54353e07fa9a701579a342a5974460889c..ae892eef8b825fb95a94b8ff37a7aa31c203d006 100644 (file)
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -124,10 +124,10 @@ 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 3512bba20e2b853d9085cbbc29a838638d9d267d..6c0c4f48638ec966cd1f9c52e068427222b903dc 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -547,8 +547,8 @@ 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;
@@ -579,7 +579,6 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
        }
 
        set_zone_contiguous(zone);
-       return 0;
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */