Merge branch 'akpm' (patches from Andrew)

Merge misc updates from Andrew Morton:

 - a few random little subsystems

 - almost all of the MM patches which are staged ahead of linux-next
   material. I'll trickle to post-linux-next work in as the dependents
   get merged up.

Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits)
  mm: cleanup kstrto*() usage
  mm: fix fall-through warnings for Clang
  mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
  mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
  mm:backing-dev: use sysfs_emit in macro defining functions
  mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
  mm: use sysfs_emit for struct kobject * uses
  mm: fix kernel-doc markups
  zram: break the strict dependency from lzo
  zram: add stat to gather incompressible pages since zram set up
  zram: support page writeback
  mm/process_vm_access: remove redundant initialization of iov_r
  mm/zsmalloc.c: rework the list_add code in insert_zspage()
  mm/zswap: move to use crypto_acomp API for hardware acceleration
  mm/zswap: fix passing zero to 'PTR_ERR' warning
  mm/zswap: make struct kernel_param_ops definitions const
  userfaultfd/selftests: hint the test runner on required privilege
  userfaultfd/selftests: fix retval check for userfaultfd_open()
  userfaultfd/selftests: always dump something in modes
  userfaultfd: selftests: make __{s,u}64 format specifiers portable
  ...

1 files changed, 7 insertions, 49 deletions

diff --git a/mm/page_poison.c b/mm/page_poison.c
index ae0482cded87..06ec518b2089 100644
--- a/mm/page_poison.c
+++ b/mm/page_poison.c
@@ -8,45 +8,17 @@
 #include <linux/ratelimit.h>
 #include <linux/kasan.h>
 
-static DEFINE_STATIC_KEY_FALSE_RO(want_page_poisoning);
+bool _page_poisoning_enabled_early;
+EXPORT_SYMBOL(_page_poisoning_enabled_early);
+DEFINE_STATIC_KEY_FALSE(_page_poisoning_enabled);
+EXPORT_SYMBOL(_page_poisoning_enabled);
 
 static int __init early_page_poison_param(char *buf)
 {
-	int ret;
-	bool tmp;
-
-	ret = strtobool(buf, &tmp);
-	if (ret)
-		return ret;
-
-	if (tmp)
-		static_branch_enable(&want_page_poisoning);
-	else
-		static_branch_disable(&want_page_poisoning);
-
-	return 0;
+	return kstrtobool(buf, &_page_poisoning_enabled_early);
 }
 early_param("page_poison", early_page_poison_param);
 
-/**
- * page_poisoning_enabled - check if page poisoning is enabled
- *
- * Return true if page poisoning is enabled, or false if not.
- */
-bool page_poisoning_enabled(void)
-{
-	/*
-	 * Assumes that debug_pagealloc_enabled is set before
-	 * memblock_free_all.
-	 * Page poisoning is debug page alloc for some arches. If
-	 * either of those options are enabled, enable poisoning.
-	 */
-	return (static_branch_unlikely(&want_page_poisoning) ||
-		(!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
-		debug_pagealloc_enabled()));
-}
-EXPORT_SYMBOL_GPL(page_poisoning_enabled);
-
 static void poison_page(struct page *page)
 {
 	void *addr = kmap_atomic(page);
@@ -58,7 +30,7 @@ static void poison_page(struct page *page)
 	kunmap_atomic(addr);
 }
 
-static void poison_pages(struct page *page, int n)
+void __kernel_poison_pages(struct page *page, int n)
 {
 	int i;
 
@@ -79,9 +51,6 @@ static void check_poison_mem(unsigned char *mem, size_t bytes)
 	unsigned char *start;
 	unsigned char *end;
 
-	if (IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY))
-		return;
-
 	start = memchr_inv(mem, PAGE_POISON, bytes);
 	if (!start)
 		return;
@@ -117,7 +86,7 @@ static void unpoison_page(struct page *page)
 	kunmap_atomic(addr);
 }
 
-static void unpoison_pages(struct page *page, int n)
+void __kernel_unpoison_pages(struct page *page, int n)
 {
 	int i;
 
@@ -125,17 +94,6 @@ static void unpoison_pages(struct page *page, int n)
 		unpoison_page(page + i);
 }
 
-void kernel_poison_pages(struct page *page, int numpages, int enable)
-{
-	if (!page_poisoning_enabled())
-		return;
-
-	if (enable)
-		unpoison_pages(page, numpages);
-	else
-		poison_pages(page, numpages);
-}
-
 #ifndef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC
 void __kernel_map_pages(struct page *page, int numpages, int enable)
 {