Commit 5a2ffca3 authored by Oscar Salvador's avatar Oscar Salvador Committed by Linus Torvalds
Browse files

mm,hwpoison: return 0 if the page is already poisoned in soft-offline 



Currently, there is an inconsistency when calling soft-offline from
different paths on a page that is already poisoned.

1) madvise:

        madvise_inject_error skips any poisoned page and continues
        the loop.
        If that was the only page to madvise, it returns 0.

2) /sys/devices/system/memory/:

        When calling soft_offline_page_store()->soft_offline_page(),
        we return -EBUSY in case the page is already poisoned.
        This is inconsistent with a) the above example and b)
        memory_failure, where we return 0 if the page was poisoned.

Fix this by dropping the PageHWPoison() check in madvise_inject_error, and
let soft_offline_page return 0 if it finds the page already poisoned.

Please, note that this represents a user-api change, since now the return
error when calling soft_offline_page_store()->soft_offline_page() will be
different.

Signed-off-by: default avatarOscar Salvador <osalvador@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarNaoya Horiguchi <naoya.horiguchi@nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200922135650.1634-12-osalvador@suse.de


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6b9a217e

mm/madvise.c

+0 −5
Original line number Diff line number Diff line
@@ -896,11 +896,6 @@ static int madvise_inject_error(int behavior, 
		 */

		size = page_size(compound_head(page));



		if (PageHWPoison(page)) {

			put_page(page);

			continue;

		}



		if (behavior == MADV_SOFT_OFFLINE) {

			pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",

				 pfn, start);

mm/memory-failure.c

+2 −2
Original line number Diff line number Diff line
@@ -1802,7 +1802,7 @@ static int __soft_offline_page(struct page *page) 
		unlock_page(page);

		put_page(page);

		pr_info("soft offline: %#lx page already poisoned\n", pfn);

		return -EBUSY;

		return 0;

	}



	if (!PageHuge(page))
@@ -1906,7 +1906,7 @@ int soft_offline_page(unsigned long pfn, int flags) 
		pr_info("soft offline: %#lx page already poisoned\n", pfn);

		if (flags & MF_COUNT_INCREASED)

			put_page(page);

		return -EBUSY;

		return 0;

	}



	get_online_mems();