Commit dd8e2f23 authored by Oscar Salvador's avatar Oscar Salvador Committed by Linus Torvalds
Browse files

mm,memory_hotplug: relax fully spanned sections check 

We want {online,offline}_pages to operate on whole memblocks, but
memmap_on_memory will poke pageblock_nr_pages aligned holes in the
beginning, which is a special case we want to allow.  Relax the check to
account for that case.

Link: https://lkml.kernel.org/r/20210421102701.25051-3-osalvador@suse.de


Signed-off-by: default avatarOscar Salvador <osalvador@suse.de>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8736cc2d

mm/memory_hotplug.c

+18 −4
Original line number Original line Diff line number Diff line
@@ -838,9 +838,16 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, 
	int ret;

	int ret;

	struct memory_notify arg;

	struct memory_notify arg;





	/* We can only online full sections (e.g., SECTION_IS_ONLINE) */

	/*

	 * {on,off}lining is constrained to full memory sections (or more

	 * precisly to memory blocks from the user space POV).

	 * memmap_on_memory is an exception because it reserves initial part

	 * of the physical memory space for vmemmaps. That space is pageblock

	 * aligned.

	 */

	if (WARN_ON_ONCE(!nr_pages ||

	if (WARN_ON_ONCE(!nr_pages ||

			 !IS_ALIGNED(pfn | nr_pages, PAGES_PER_SECTION)))

			 !IS_ALIGNED(pfn, pageblock_nr_pages) ||

			 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))

		return -EINVAL;

		return -EINVAL;





	mem_hotplug_begin();

	mem_hotplug_begin();
@@ -1573,9 +1580,16 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages) 
	int ret, node;

	int ret, node;

	char *reason;

	char *reason;





	/* We can only offline full sections (e.g., SECTION_IS_ONLINE) */

	/*

	 * {on,off}lining is constrained to full memory sections (or more

	 * precisly to memory blocks from the user space POV).

	 * memmap_on_memory is an exception because it reserves initial part

	 * of the physical memory space for vmemmaps. That space is pageblock

	 * aligned.

	 */

	if (WARN_ON_ONCE(!nr_pages ||

	if (WARN_ON_ONCE(!nr_pages ||

			 !IS_ALIGNED(start_pfn | nr_pages, PAGES_PER_SECTION)))

			 !IS_ALIGNED(start_pfn, pageblock_nr_pages) ||

			 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))

		return -EINVAL;

		return -EINVAL;





	mem_hotplug_begin();

	mem_hotplug_begin();