Merge branch 'akpm' (patches from Andrew)

Merge fixes from Andrew Morton:
 "11 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: silently skip readahead for DAX inodes
  dax: fix device-dax region base
  fs/seq_file: fix out-of-bounds read
  mm: memcontrol: avoid unused function warning
  mm: clarify COMPACTION Kconfig text
  treewide: replace config_enabled() with IS_ENABLED() (2nd round)
  printk: fix parsing of "brl=" option
  soft_dirty: fix soft_dirty during THP split
  sysctl: handle error writing UINT_MAX to u32 fields
  get_maintainer: quiet noisy implicit -f vcs_file_exists checking
  byteswap: don't use __builtin_bswap*() with sparse

14 files changed, 108 insertions, 35 deletions

diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
index ea0cd9773914..5f987598054f 100644
--- a/arch/mips/include/asm/page.h
+++ b/arch/mips/include/asm/page.h
@@ -164,7 +164,7 @@ typedef struct { unsigned long pgprot; } pgprot_t;
  */
 static inline unsigned long ___pa(unsigned long x)
 {
-	if (config_enabled(CONFIG_64BIT)) {
+	if (IS_ENABLED(CONFIG_64BIT)) {
 		/*
 		 * For MIPS64 the virtual address may either be in one of
 		 * the compatibility segements ckseg0 or ckseg1, or it may
@@ -173,7 +173,7 @@ static inline unsigned long ___pa(unsigned long x)
 		return x < CKSEG0 ? XPHYSADDR(x) : CPHYSADDR(x);
 	}
 
-	if (!config_enabled(CONFIG_EVA)) {
+	if (!IS_ENABLED(CONFIG_EVA)) {
 		/*
 		 * We're using the standard MIPS32 legacy memory map, ie.
 		 * the address x is going to be in kseg0 or kseg1. We can
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index ba5f456edaa9..7f7ba5f23f13 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -204,11 +204,9 @@ static void __init conmode_default(void)
 #endif
 		}
 	} else if (MACHINE_IS_KVM) {
-		if (sclp.has_vt220 &&
-		    config_enabled(CONFIG_SCLP_VT220_CONSOLE))
+		if (sclp.has_vt220 && IS_ENABLED(CONFIG_SCLP_VT220_CONSOLE))
 			SET_CONSOLE_VT220;
-		else if (sclp.has_linemode &&
-			 config_enabled(CONFIG_SCLP_CONSOLE))
+		else if (sclp.has_linemode && IS_ENABLED(CONFIG_SCLP_CONSOLE))
 			SET_CONSOLE_SCLP;
 		else
 			SET_CONSOLE_HVC;
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index ec8654f117d8..bda8d5eef04d 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -77,7 +77,7 @@ static inline unsigned long get_padding(struct kaslr_memory_region *region)
  */
 static inline bool kaslr_memory_enabled(void)
 {
-	return kaslr_enabled() && !config_enabled(CONFIG_KASAN);
+	return kaslr_enabled() && !IS_ENABLED(CONFIG_KASAN);
 }
 
 /* Initialize base and padding for each memory region randomized with KASLR */
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index dfb168568af1..1f01e98c83c7 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -116,6 +116,9 @@ static int dax_pmem_probe(struct device *dev)
 	if (rc)
 		return rc;
 
+	/* adjust the dax_region resource to the start of data */
+	res.start += le64_to_cpu(pfn_sb->dataoff);
+
 	nd_region = to_nd_region(dev->parent);
 	dax_region = alloc_dax_region(dev, nd_region->id, &res,
 			le32_to_cpu(pfn_sb->align), addr, PFN_DEV|PFN_MAP);
diff --git a/fs/seq_file.c b/fs/seq_file.c
index 19f532e7d35e..6dc4296eed62 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -223,8 +223,10 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 		size -= n;
 		buf += n;
 		copied += n;
-		if (!m->count)
+		if (!m->count) {
+			m->from = 0;
 			m->index++;
+		}
 		if (!size)
 			goto Done;
 	}
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index e2949397c19b..8dbc8929a6a0 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -242,7 +242,11 @@
  */
 #define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
 
-#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+/*
+ * sparse (__CHECKER__) pretends to be gcc, but can't do constant
+ * folding in __builtin_bswap*() (yet), so don't set these for it.
+ */
+#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
 #if GCC_VERSION >= 40400
 #define __HAVE_BUILTIN_BSWAP32__
 #define __HAVE_BUILTIN_BSWAP64__
@@ -250,7 +254,7 @@
 #if GCC_VERSION >= 40800
 #define __HAVE_BUILTIN_BSWAP16__
 #endif
-#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
 
 #if GCC_VERSION >= 50000
 #define KASAN_ABI_VERSION 4
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 697e160c78d0..a4f7203a9017 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -42,6 +42,8 @@ extern int proc_dostring(struct ctl_table *, int,
 			 void __user *, size_t *, loff_t *);
 extern int proc_dointvec(struct ctl_table *, int,
 			 void __user *, size_t *, loff_t *);
+extern int proc_douintvec(struct ctl_table *, int,
+			 void __user *, size_t *, loff_t *);
 extern int proc_dointvec_minmax(struct ctl_table *, int,
 				void __user *, size_t *, loff_t *);
 extern int proc_dointvec_jiffies(struct ctl_table *, int,
diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c
index 276762f3a460..d5760c42f042 100644
--- a/kernel/printk/braille.c
+++ b/kernel/printk/braille.c
@@ -9,10 +9,10 @@
 
 char *_braille_console_setup(char **str, char **brl_options)
 {
-	if (!memcmp(*str, "brl,", 4)) {
+	if (!strncmp(*str, "brl,", 4)) {
 		*brl_options = "";
 		*str += 4;
-	} else if (!memcmp(str, "brl=", 4)) {
+	} else if (!strncmp(*str, "brl=", 4)) {
 		*brl_options = *str + 4;
 		*str = strchr(*brl_options, ',');
 		if (!*str)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b43d0b27c1fe..a13bbdaab47d 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2140,6 +2140,21 @@ static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
 	return 0;
 }
 
+static int do_proc_douintvec_conv(bool *negp, unsigned long *lvalp,
+				 int *valp,
+				 int write, void *data)
+{
+	if (write) {
+		if (*negp)
+			return -EINVAL;
+		*valp = *lvalp;
+	} else {
+		unsigned int val = *valp;
+		*lvalp = (unsigned long)val;
+	}
+	return 0;
+}
+
 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
 
 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
@@ -2259,8 +2274,27 @@ static int do_proc_dointvec(struct ctl_table *table, int write,
 int proc_dointvec(struct ctl_table *table, int write,
 		     void __user *buffer, size_t *lenp, loff_t *ppos)
 {
-    return do_proc_dointvec(table,write,buffer,lenp,ppos,
-		    	    NULL,NULL);
+	return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL);
+}
+
+/**
+ * proc_douintvec - read a vector of unsigned integers
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
+ * values from/to the user buffer, treated as an ASCII string.
+ *
+ * Returns 0 on success.
+ */
+int proc_douintvec(struct ctl_table *table, int write,
+		     void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	return do_proc_dointvec(table, write, buffer, lenp, ppos,
+				do_proc_douintvec_conv, NULL);
 }
 
 /*
@@ -2858,6 +2892,12 @@ int proc_dointvec(struct ctl_table *table, int write,
 	return -ENOSYS;
 }
 
+int proc_douintvec(struct ctl_table *table, int write,
+		  void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
 int proc_dointvec_minmax(struct ctl_table *table, int write,
 		    void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -2903,6 +2943,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
  * exception granted :-)
  */
 EXPORT_SYMBOL(proc_dointvec);
+EXPORT_SYMBOL(proc_douintvec);
 EXPORT_SYMBOL(proc_dointvec_jiffies);
 EXPORT_SYMBOL(proc_dointvec_minmax);
 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
diff --git a/mm/Kconfig b/mm/Kconfig
index 78a23c5c302d..be0ee11fa0d9 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -262,7 +262,14 @@ config COMPACTION
 	select MIGRATION
 	depends on MMU
 	help
-	  Allows the compaction of memory for the allocation of huge pages.
+          Compaction is the only memory management component to form
+          high order (larger physically contiguous) memory blocks
+          reliably. The page allocator relies on compaction heavily and
+          the lack of the feature can lead to unexpected OOM killer
+          invocations for high order memory requests. You shouldn't
+          disable this option unless there really is a strong reason for
+          it and then we would be really interested to hear about that at
+          linux-mm@kvack.org.
 
 #
 # support for page migration
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2373f0a7d340..2db2112aa31e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1512,7 +1512,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 	struct page *page;
 	pgtable_t pgtable;
 	pmd_t _pmd;
-	bool young, write, dirty;
+	bool young, write, dirty, soft_dirty;
 	unsigned long addr;
 	int i;
 
@@ -1546,6 +1546,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 	write = pmd_write(*pmd);
 	young = pmd_young(*pmd);
 	dirty = pmd_dirty(*pmd);
+	soft_dirty = pmd_soft_dirty(*pmd);
 
 	pmdp_huge_split_prepare(vma, haddr, pmd);
 	pgtable = pgtable_trans_huge_withdraw(mm, pmd);
@@ -1562,6 +1563,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 			swp_entry_t swp_entry;
 			swp_entry = make_migration_entry(page + i, write);
 			entry = swp_entry_to_pte(swp_entry);
+			if (soft_dirty)
+				entry = pte_swp_mksoft_dirty(entry);
 		} else {
 			entry = mk_pte(page + i, vma->vm_page_prot);
 			entry = maybe_mkwrite(entry, vma);
@@ -1569,6 +1572,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 				entry = pte_wrprotect(entry);
 			if (!young)
 				entry = pte_mkold(entry);
+			if (soft_dirty)
+				entry = pte_mksoft_dirty(entry);
 		}
 		if (dirty)
 			SetPageDirty(page + i);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2ff0289ad061..9a6a51a7c416 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4082,24 +4082,6 @@ static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
 	atomic_add(n, &memcg->id.ref);
 }
 
-static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
-{
-	while (!atomic_inc_not_zero(&memcg->id.ref)) {
-		/*
-		 * The root cgroup cannot be destroyed, so it's refcount must
-		 * always be >= 1.
-		 */
-		if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
-			VM_BUG_ON(1);
-			break;
-		}
-		memcg = parent_mem_cgroup(memcg);
-		if (!memcg)
-			memcg = root_mem_cgroup;
-	}
-	return memcg;
-}
-
 static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
 {
 	if (atomic_sub_and_test(n, &memcg->id.ref)) {
@@ -5821,6 +5803,24 @@ static int __init mem_cgroup_init(void)
 subsys_initcall(mem_cgroup_init);
 
 #ifdef CONFIG_MEMCG_SWAP
+static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
+{
+	while (!atomic_inc_not_zero(&memcg->id.ref)) {
+		/*
+		 * The root cgroup cannot be destroyed, so it's refcount must
+		 * always be >= 1.
+		 */
+		if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
+			VM_BUG_ON(1);
+			break;
+		}
+		memcg = parent_mem_cgroup(memcg);
+		if (!memcg)
+			memcg = root_mem_cgroup;
+	}
+	return memcg;
+}
+
 /**
  * mem_cgroup_swapout - transfer a memsw charge to swap
  * @page: page whose memsw charge to transfer
diff --git a/mm/readahead.c b/mm/readahead.c
index 65ec288dc057..c8a955b1297e 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/dax.h>
 #include <linux/gfp.h>
 #include <linux/export.h>
 #include <linux/blkdev.h>
@@ -544,6 +545,14 @@ do_readahead(struct address_space *mapping, struct file *filp,
 	if (!mapping || !mapping->a_ops)
 		return -EINVAL;
 
+	/*
+	 * Readahead doesn't make sense for DAX inodes, but we don't want it
+	 * to report a failure either.  Instead, we just return success and
+	 * don't do any work.
+	 */
+	if (dax_mapping(mapping))
+		return 0;
+
 	return force_page_cache_readahead(mapping, filp, index, nr);
 }
 
diff --git a/scripts/get_maintainer.pl b/scripts/get_maintainer.pl
index 49a00d54b835..aed4511f0304 100755
--- a/scripts/get_maintainer.pl
+++ b/scripts/get_maintainer.pl
@@ -2136,9 +2136,11 @@ sub vcs_file_exists {
 
     my $cmd = $VCS_cmds{"file_exists_cmd"};
     $cmd =~ s/(\$\w+)/$1/eeg;		# interpolate $cmd
-
+    $cmd .= " 2>&1";
     $exists = &{$VCS_cmds{"execute_cmd"}}($cmd);
 
+    return 0 if ($? != 0);
+
     return $exists;
 }