Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "14 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kernel/sysctl.c: fix out-of-bounds access when setting file-max
  mm/util.c: fix strndup_user() comment
  sh: fix multiple function definition build errors
  MAINTAINERS: add maintainer and replacing reviewer ARM/NUVOTON NPCM
  MAINTAINERS: fix bad pattern in ARM/NUVOTON NPCM
  mm: writeback: use exact memcg dirty counts
  psi: clarify the units used in pressure files
  mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()
  hugetlbfs: fix memory leak for resv_map
  mm: fix vm_fault_t cast in VM_FAULT_GET_HINDEX()
  lib/lzo: fix bugs for very short or empty input
  include/linux/bitrev.h: fix constant bitrev
  kmemleak: powerpc: skip scanning holes in the .bss section
  lib/string.c: implement a basic bcmp

18 files changed, 163 insertions, 59 deletions

diff --git a/Documentation/accounting/psi.txt b/Documentation/accounting/psi.txt
index b8ca28b60215..7e71c9c1d8e9 100644
--- a/Documentation/accounting/psi.txt
+++ b/Documentation/accounting/psi.txt
@@ -56,12 +56,12 @@ situation from a state where some tasks are stalled but the CPU is
 still doing productive work. As such, time spent in this subset of the
 stall state is tracked separately and exported in the "full" averages.
 
-The ratios are tracked as recent trends over ten, sixty, and three
-hundred second windows, which gives insight into short term events as
-well as medium and long term trends. The total absolute stall time is
-tracked and exported as well, to allow detection of latency spikes
-which wouldn't necessarily make a dent in the time averages, or to
-average trends over custom time frames.
+The ratios (in %) are tracked as recent trends over ten, sixty, and
+three hundred second windows, which gives insight into short term events
+as well as medium and long term trends. The total absolute stall time
+(in us) is tracked and exported as well, to allow detection of latency
+spikes which wouldn't necessarily make a dent in the time averages,
+or to average trends over custom time frames.
 
 Cgroup2 interface
 =================
diff --git a/Documentation/lzo.txt b/Documentation/lzo.txt
index f79934225d8d..ca983328976b 100644
--- a/Documentation/lzo.txt
+++ b/Documentation/lzo.txt
@@ -102,9 +102,11 @@ Byte sequences
                 dictionary which is empty, and that it will always be
                 invalid at this place.
 
-      17      : bitstream version. If the first byte is 17, the next byte
-                gives the bitstream version (version 1 only). If the first byte
-                is not 17, the bitstream version is 0.
+      17      : bitstream version. If the first byte is 17, and compressed
+                stream length is at least 5 bytes (length of shortest possible
+                versioned bitstream), the next byte gives the bitstream version
+                (version 1 only).
+                Otherwise, the bitstream version is 0.
 
       18..21  : copy 0..3 literals
                 state = (byte - 17) = 0..3  [ copy <state> literals ]
diff --git a/MAINTAINERS b/MAINTAINERS
index 6771bd784f5f..2359e12e4c41 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1893,14 +1893,15 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-nomadik.git
 ARM/NUVOTON NPCM ARCHITECTURE
 M:	Avi Fishman <avifishman70@gmail.com>
 M:	Tomer Maimon <tmaimon77@gmail.com>
+M:	Tali Perry <tali.perry1@gmail.com>
 R:	Patrick Venture <venture@google.com>
 R:	Nancy Yuen <yuenn@google.com>
-R:	Brendan Higgins <brendanhiggins@google.com>
+R:	Benjamin Fair <benjaminfair@google.com>
 L:	openbmc@lists.ozlabs.org (moderated for non-subscribers)
 S:	Supported
 F:	arch/arm/mach-npcm/
 F:	arch/arm/boot/dts/nuvoton-npcm*
-F:	include/dt-bindings/clock/nuvoton,npcm7xx-clks.h
+F:	include/dt-bindings/clock/nuvoton,npcm7xx-clock.h
 F:	drivers/*/*npcm*
 F:	Documentation/devicetree/bindings/*/*npcm*
 F:	Documentation/devicetree/bindings/*/*/*npcm*
diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index 683b5b3805bd..cd381e2291df 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -22,6 +22,7 @@
 #include <linux/kvm_host.h>
 #include <linux/init.h>
 #include <linux/export.h>
+#include <linux/kmemleak.h>
 #include <linux/kvm_para.h>
 #include <linux/slab.h>
 #include <linux/of.h>
@@ -712,6 +713,12 @@ static void kvm_use_magic_page(void)
 
 static __init void kvm_free_tmp(void)
 {
+	/*
+	 * Inform kmemleak about the hole in the .bss section since the
+	 * corresponding pages will be unmapped with DEBUG_PAGEALLOC=y.
+	 */
+	kmemleak_free_part(&kvm_tmp[kvm_tmp_index],
+			   ARRAY_SIZE(kvm_tmp) - kvm_tmp_index);
 	free_reserved_area(&kvm_tmp[kvm_tmp_index],
 			   &kvm_tmp[ARRAY_SIZE(kvm_tmp)], -1, NULL);
 }
diff --git a/arch/sh/boards/of-generic.c b/arch/sh/boards/of-generic.c
index 958f46da3a79..d91065e81a4e 100644
--- a/arch/sh/boards/of-generic.c
+++ b/arch/sh/boards/of-generic.c
@@ -164,10 +164,10 @@ static struct sh_machine_vector __initmv sh_of_generic_mv = {
 
 struct sh_clk_ops;
 
-void __init arch_init_clk_ops(struct sh_clk_ops **ops, int idx)
+void __init __weak arch_init_clk_ops(struct sh_clk_ops **ops, int idx)
 {
 }
 
-void __init plat_irq_setup(void)
+void __init __weak plat_irq_setup(void)
 {
 }
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index ec32fece5e1e..9285dd4f4b1c 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -755,11 +755,17 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 					umode_t mode, dev_t dev)
 {
 	struct inode *inode;
-	struct resv_map *resv_map;
+	struct resv_map *resv_map = NULL;
 
-	resv_map = resv_map_alloc();
-	if (!resv_map)
-		return NULL;
+	/*
+	 * Reserve maps are only needed for inodes that can have associated
+	 * page allocations.
+	 */
+	if (S_ISREG(mode) || S_ISLNK(mode)) {
+		resv_map = resv_map_alloc();
+		if (!resv_map)
+			return NULL;
+	}
 
 	inode = new_inode(sb);
 	if (inode) {
@@ -794,8 +800,10 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 			break;
 		}
 		lockdep_annotate_inode_mutex_key(inode);
-	} else
-		kref_put(&resv_map->refs, resv_map_release);
+	} else {
+		if (resv_map)
+			kref_put(&resv_map->refs, resv_map_release);
+	}
 
 	return inode;
 }
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index 50fb0dee23e8..d35b8ec1c485 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -34,41 +34,41 @@ static inline u32 __bitrev32(u32 x)
 
 #define __constant_bitrev32(x)	\
 ({					\
-	u32 __x = x;			\
-	__x = (__x >> 16) | (__x << 16);	\
-	__x = ((__x & (u32)0xFF00FF00UL) >> 8) | ((__x & (u32)0x00FF00FFUL) << 8);	\
-	__x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4);	\
-	__x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2);	\
-	__x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1);	\
-	__x;								\
+	u32 ___x = x;			\
+	___x = (___x >> 16) | (___x << 16);	\
+	___x = ((___x & (u32)0xFF00FF00UL) >> 8) | ((___x & (u32)0x00FF00FFUL) << 8);	\
+	___x = ((___x & (u32)0xF0F0F0F0UL) >> 4) | ((___x & (u32)0x0F0F0F0FUL) << 4);	\
+	___x = ((___x & (u32)0xCCCCCCCCUL) >> 2) | ((___x & (u32)0x33333333UL) << 2);	\
+	___x = ((___x & (u32)0xAAAAAAAAUL) >> 1) | ((___x & (u32)0x55555555UL) << 1);	\
+	___x;								\
 })
 
 #define __constant_bitrev16(x)	\
 ({					\
-	u16 __x = x;			\
-	__x = (__x >> 8) | (__x << 8);	\
-	__x = ((__x & (u16)0xF0F0U) >> 4) | ((__x & (u16)0x0F0FU) << 4);	\
-	__x = ((__x & (u16)0xCCCCU) >> 2) | ((__x & (u16)0x3333U) << 2);	\
-	__x = ((__x & (u16)0xAAAAU) >> 1) | ((__x & (u16)0x5555U) << 1);	\
-	__x;								\
+	u16 ___x = x;			\
+	___x = (___x >> 8) | (___x << 8);	\
+	___x = ((___x & (u16)0xF0F0U) >> 4) | ((___x & (u16)0x0F0FU) << 4);	\
+	___x = ((___x & (u16)0xCCCCU) >> 2) | ((___x & (u16)0x3333U) << 2);	\
+	___x = ((___x & (u16)0xAAAAU) >> 1) | ((___x & (u16)0x5555U) << 1);	\
+	___x;								\
 })
 
 #define __constant_bitrev8x4(x) \
 ({			\
-	u32 __x = x;	\
-	__x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4);	\
-	__x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2);	\
-	__x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1);	\
-	__x;								\
+	u32 ___x = x;	\
+	___x = ((___x & (u32)0xF0F0F0F0UL) >> 4) | ((___x & (u32)0x0F0F0F0FUL) << 4);	\
+	___x = ((___x & (u32)0xCCCCCCCCUL) >> 2) | ((___x & (u32)0x33333333UL) << 2);	\
+	___x = ((___x & (u32)0xAAAAAAAAUL) >> 1) | ((___x & (u32)0x55555555UL) << 1);	\
+	___x;								\
 })
 
 #define __constant_bitrev8(x)	\
 ({					\
-	u8 __x = x;			\
-	__x = (__x >> 4) | (__x << 4);	\
-	__x = ((__x & (u8)0xCCU) >> 2) | ((__x & (u8)0x33U) << 2);	\
-	__x = ((__x & (u8)0xAAU) >> 1) | ((__x & (u8)0x55U) << 1);	\
-	__x;								\
+	u8 ___x = x;			\
+	___x = (___x >> 4) | (___x << 4);	\
+	___x = ((___x & (u8)0xCCU) >> 2) | ((___x & (u8)0x33U) << 2);	\
+	___x = ((___x & (u8)0xAAU) >> 1) | ((___x & (u8)0x55U) << 1);	\
+	___x;								\
 })
 
 #define bitrev32(x) \
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 1f3d880b7ca1..dbb6118370c1 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -566,7 +566,10 @@ struct mem_cgroup *lock_page_memcg(struct page *page);
 void __unlock_page_memcg(struct mem_cgroup *memcg);
 void unlock_page_memcg(struct page *page);
 
-/* idx can be of type enum memcg_stat_item or node_stat_item */
+/*
+ * idx can be of type enum memcg_stat_item or node_stat_item.
+ * Keep in sync with memcg_exact_page_state().
+ */
 static inline unsigned long memcg_page_state(struct mem_cgroup *memcg,
 					     int idx)
 {
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 7eade9132f02..4ef4bbe78a1d 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -671,7 +671,7 @@ enum vm_fault_reason {
 
 /* Encode hstate index for a hwpoisoned large page */
 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
-#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf)
+#define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
 
 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS |	\
 			VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON |	\
diff --git a/include/linux/string.h b/include/linux/string.h
index 7927b875f80c..6ab0a6fa512e 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -150,6 +150,9 @@ extern void * memscan(void *,int,__kernel_size_t);
 #ifndef __HAVE_ARCH_MEMCMP
 extern int memcmp(const void *,const void *,__kernel_size_t);
 #endif
+#ifndef __HAVE_ARCH_BCMP
+extern int bcmp(const void *,const void *,__kernel_size_t);
+#endif
 #ifndef __HAVE_ARCH_MEMCHR
 extern void * memchr(const void *,int,__kernel_size_t);
 #endif
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index e5da394d1ca3..c9ec050bcf46 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -128,6 +128,7 @@ static int zero;
 static int __maybe_unused one = 1;
 static int __maybe_unused two = 2;
 static int __maybe_unused four = 4;
+static unsigned long zero_ul;
 static unsigned long one_ul = 1;
 static unsigned long long_max = LONG_MAX;
 static int one_hundred = 100;
@@ -1750,7 +1751,7 @@ static struct ctl_table fs_table[] = {
 		.maxlen		= sizeof(files_stat.max_files),
 		.mode		= 0644,
 		.proc_handler	= proc_doulongvec_minmax,
-		.extra1		= &zero,
+		.extra1		= &zero_ul,
 		.extra2		= &long_max,
 	},
 	{
diff --git a/lib/lzo/lzo1x_compress.c b/lib/lzo/lzo1x_compress.c
index 4525fb094844..a8ede77afe0d 100644
--- a/lib/lzo/lzo1x_compress.c
+++ b/lib/lzo/lzo1x_compress.c
@@ -291,13 +291,14 @@ int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
 {
 	const unsigned char *ip = in;
 	unsigned char *op = out;
+	unsigned char *data_start;
 	size_t l = in_len;
 	size_t t = 0;
 	signed char state_offset = -2;
 	unsigned int m4_max_offset;
 
-	// LZO v0 will never write 17 as first byte,
-	// so this is used to version the bitstream
+	// LZO v0 will never write 17 as first byte (except for zero-length
+	// input), so this is used to version the bitstream
 	if (bitstream_version > 0) {
 		*op++ = 17;
 		*op++ = bitstream_version;
@@ -306,6 +307,8 @@ int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
 		m4_max_offset = M4_MAX_OFFSET_V0;
 	}
 
+	data_start = op;
+
 	while (l > 20) {
 		size_t ll = l <= (m4_max_offset + 1) ? l : (m4_max_offset + 1);
 		uintptr_t ll_end = (uintptr_t) ip + ll;
@@ -324,7 +327,7 @@ int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
 	if (t > 0) {
 		const unsigned char *ii = in + in_len - t;
 
-		if (op == out && t <= 238) {
+		if (op == data_start && t <= 238) {
 			*op++ = (17 + t);
 		} else if (t <= 3) {
 			op[state_offset] |= t;
diff --git a/lib/lzo/lzo1x_decompress_safe.c b/lib/lzo/lzo1x_decompress_safe.c
index 6d2600ea3b55..9e07e9ef1aad 100644
--- a/lib/lzo/lzo1x_decompress_safe.c
+++ b/lib/lzo/lzo1x_decompress_safe.c
@@ -54,11 +54,9 @@ int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
 	if (unlikely(in_len < 3))
 		goto input_overrun;
 
-	if (likely(*ip == 17)) {
+	if (likely(in_len >= 5) && likely(*ip == 17)) {
 		bitstream_version = ip[1];
 		ip += 2;
-		if (unlikely(in_len < 5))
-			goto input_overrun;
 	} else {
 		bitstream_version = 0;
 	}
diff --git a/lib/string.c b/lib/string.c
index 38e4ca08e757..3ab861c1a857 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -866,6 +866,26 @@ __visible int memcmp(const void *cs, const void *ct, size_t count)
 EXPORT_SYMBOL(memcmp);
 #endif
 
+#ifndef __HAVE_ARCH_BCMP
+/**
+ * bcmp - returns 0 if and only if the buffers have identical contents.
+ * @a: pointer to first buffer.
+ * @b: pointer to second buffer.
+ * @len: size of buffers.
+ *
+ * The sign or magnitude of a non-zero return value has no particular
+ * meaning, and architectures may implement their own more efficient bcmp(). So
+ * while this particular implementation is a simple (tail) call to memcmp, do
+ * not rely on anything but whether the return value is zero or non-zero.
+ */
+#undef bcmp
+int bcmp(const void *a, const void *b, size_t len)
+{
+	return memcmp(a, b, len);
+}
+EXPORT_SYMBOL(bcmp);
+#endif
+
 #ifndef __HAVE_ARCH_MEMSCAN
 /**
  * memscan - Find a character in an area of memory.
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 404acdcd0455..165ea46bf149 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -755,6 +755,21 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
 	spinlock_t *ptl;
 
 	ptl = pmd_lock(mm, pmd);
+	if (!pmd_none(*pmd)) {
+		if (write) {
+			if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) {
+				WARN_ON_ONCE(!is_huge_zero_pmd(*pmd));
+				goto out_unlock;
+			}
+			entry = pmd_mkyoung(*pmd);
+			entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+			if (pmdp_set_access_flags(vma, addr, pmd, entry, 1))
+				update_mmu_cache_pmd(vma, addr, pmd);
+		}
+
+		goto out_unlock;
+	}
+
 	entry = pmd_mkhuge(pfn_t_pmd(pfn, prot));
 	if (pfn_t_devmap(pfn))
 		entry = pmd_mkdevmap(entry);
@@ -766,11 +781,16 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
 	if (pgtable) {
 		pgtable_trans_huge_deposit(mm, pmd, pgtable);
 		mm_inc_nr_ptes(mm);
+		pgtable = NULL;
 	}
 
 	set_pmd_at(mm, addr, pmd, entry);
 	update_mmu_cache_pmd(vma, addr, pmd);
+
+out_unlock:
 	spin_unlock(ptl);
+	if (pgtable)
+		pte_free(mm, pgtable);
 }
 
 vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
@@ -821,6 +841,20 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
 	spinlock_t *ptl;
 
 	ptl = pud_lock(mm, pud);
+	if (!pud_none(*pud)) {
+		if (write) {
+			if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) {
+				WARN_ON_ONCE(!is_huge_zero_pud(*pud));
+				goto out_unlock;
+			}
+			entry = pud_mkyoung(*pud);
+			entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
+			if (pudp_set_access_flags(vma, addr, pud, entry, 1))
+				update_mmu_cache_pud(vma, addr, pud);
+		}
+		goto out_unlock;
+	}
+
 	entry = pud_mkhuge(pfn_t_pud(pfn, prot));
 	if (pfn_t_devmap(pfn))
 		entry = pud_mkdevmap(entry);
@@ -830,6 +864,8 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
 	}
 	set_pud_at(mm, addr, pud, entry);
 	update_mmu_cache_pud(vma, addr, pud);
+
+out_unlock:
 	spin_unlock(ptl);
 }
 
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 707fa5579f66..6c318f5ac234 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1529,11 +1529,6 @@ static void kmemleak_scan(void)
 	}
 	rcu_read_unlock();
 
-	/* data/bss scanning */
-	scan_large_block(_sdata, _edata);
-	scan_large_block(__bss_start, __bss_stop);
-	scan_large_block(__start_ro_after_init, __end_ro_after_init);
-
 #ifdef CONFIG_SMP
 	/* per-cpu sections scanning */
 	for_each_possible_cpu(i)
@@ -2071,6 +2066,17 @@ void __init kmemleak_init(void)
 	}
 	local_irq_restore(flags);
 
+	/* register the data/bss sections */
+	create_object((unsigned long)_sdata, _edata - _sdata,
+		      KMEMLEAK_GREY, GFP_ATOMIC);
+	create_object((unsigned long)__bss_start, __bss_stop - __bss_start,
+		      KMEMLEAK_GREY, GFP_ATOMIC);
+	/* only register .data..ro_after_init if not within .data */
+	if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
+		create_object((unsigned long)__start_ro_after_init,
+			      __end_ro_after_init - __start_ro_after_init,
+			      KMEMLEAK_GREY, GFP_ATOMIC);
+
 	/*
 	 * This is the point where tracking allocations is safe. Automatic
 	 * scanning is started during the late initcall. Add the early logged
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 532e0e2a4817..81a0d3914ec9 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3882,6 +3882,22 @@ struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
 	return &memcg->cgwb_domain;
 }
 
+/*
+ * idx can be of type enum memcg_stat_item or node_stat_item.
+ * Keep in sync with memcg_exact_page().
+ */
+static unsigned long memcg_exact_page_state(struct mem_cgroup *memcg, int idx)
+{
+	long x = atomic_long_read(&memcg->stat[idx]);
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		x += per_cpu_ptr(memcg->stat_cpu, cpu)->count[idx];
+	if (x < 0)
+		x = 0;
+	return x;
+}
+
 /**
  * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
  * @wb: bdi_writeback in question
@@ -3907,10 +3923,10 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
 	struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
 	struct mem_cgroup *parent;
 
-	*pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
+	*pdirty = memcg_exact_page_state(memcg, NR_FILE_DIRTY);
 
 	/* this should eventually include NR_UNSTABLE_NFS */
-	*pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
+	*pwriteback = memcg_exact_page_state(memcg, NR_WRITEBACK);
 	*pfilepages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
 						     (1 << LRU_ACTIVE_FILE));
 	*pheadroom = PAGE_COUNTER_MAX;
diff --git a/mm/util.c b/mm/util.c
index d559bde497a9..43a2984bccaa 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -204,7 +204,7 @@ EXPORT_SYMBOL(vmemdup_user);
  * @s: The string to duplicate
  * @n: Maximum number of bytes to copy, including the trailing NUL.
  *
- * Return: newly allocated copy of @s or %NULL in case of error
+ * Return: newly allocated copy of @s or an ERR_PTR() in case of error
  */
 char *strndup_user(const char __user *s, long n)
 {