Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
 "The rest of MM"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (101 commits)
  mm, compaction: simplify contended compaction handling
  mm, compaction: introduce direct compaction priority
  mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations
  mm, page_alloc: make THP-specific decisions more generic
  mm, page_alloc: restructure direct compaction handling in slowpath
  mm, page_alloc: don't retry initial attempt in slowpath
  mm, page_alloc: set alloc_flags only once in slowpath
  lib/stackdepot.c: use __GFP_NOWARN for stack allocations
  mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB
  mm, kasan: account for object redzone in SLUB's nearest_obj()
  mm: fix use-after-free if memory allocation failed in vma_adjust()
  zsmalloc: Delete an unnecessary check before the function call "iput"
  mm/memblock.c: fix index adjustment error in __next_mem_range_rev()
  mem-hotplug: alloc new page from a nearest neighbor node when mem-offline
  mm: optimize copy_page_to/from_iter_iovec
  mm: add cond_resched() to generic_swapfile_activate()
  Revert "mm, mempool: only set __GFP_NOMEMALLOC if there are free elements"
  mm, compaction: don't isolate PageWriteback pages in MIGRATE_SYNC_LIGHT mode
  mm: hwpoison: remove incorrect comments
  make __section_nr() more efficient
  ...

lib/Kconfig.kasan

@@ -5,9 +5,9 @@ if HAVE_ARCH_KASAN
 
 config KASAN
 	bool "KASan: runtime memory debugger"
-	depends on SLUB_DEBUG || (SLAB && !DEBUG_SLAB)
+	depends on SLUB || (SLAB && !DEBUG_SLAB)
 	select CONSTRUCTORS
-	select STACKDEPOT if SLAB
+	select STACKDEPOT
 	help
 	  Enables kernel address sanitizer - runtime memory debugger,
 	  designed to find out-of-bounds accesses and use-after-free bugs.

lib/iov_iter.c

@@ -144,7 +144,7 @@ static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t b
 	buf = iov->iov_base + skip;
 	copy = min(bytes, iov->iov_len - skip);
 
-	if (!fault_in_pages_writeable(buf, copy)) {
+	if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) {
 		kaddr = kmap_atomic(page);
 		from = kaddr + offset;
 
@@ -175,6 +175,7 @@ static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t b
 		copy = min(bytes, iov->iov_len - skip);
 	}
 	/* Too bad - revert to non-atomic kmap */
+
 	kaddr = kmap(page);
 	from = kaddr + offset;
 	left = __copy_to_user(buf, from, copy);
@@ -193,6 +194,7 @@ static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t b
 		bytes -= copy;
 	}
 	kunmap(page);
+
 done:
 	if (skip == iov->iov_len) {
 		iov++;
@@ -225,7 +227,7 @@ static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t
 	buf = iov->iov_base + skip;
 	copy = min(bytes, iov->iov_len - skip);
 
-	if (!fault_in_pages_readable(buf, copy)) {
+	if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) {
 		kaddr = kmap_atomic(page);
 		to = kaddr + offset;
 
@@ -256,6 +258,7 @@ static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t
 		copy = min(bytes, iov->iov_len - skip);
 	}
 	/* Too bad - revert to non-atomic kmap */
+
 	kaddr = kmap(page);
 	to = kaddr + offset;
 	left = __copy_from_user(to, buf, copy);
@@ -274,6 +277,7 @@ static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t
 		bytes -= copy;
 	}
 	kunmap(page);
+
 done:
 	if (skip == iov->iov_len) {
 		iov++;

lib/stackdepot.c

@@ -242,6 +242,7 @@ depot_stack_handle_t depot_save_stack(struct stack_trace *trace,
 		 */
 		alloc_flags &= ~GFP_ZONEMASK;
 		alloc_flags &= (GFP_ATOMIC | GFP_KERNEL);
+		alloc_flags |= __GFP_NOWARN;
 		page = alloc_pages(alloc_flags, STACK_ALLOC_ORDER);
 		if (page)
 			prealloc = page_address(page);