Merge branch 'akpm' (patches from Andrew)

Merge fixes from Andrew Morton:
 "26 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (26 commits)
  MAINTAINERS: add Dan Streetman to zbud maintainers
  MAINTAINERS: add Dan Streetman to zswap maintainers
  mm: do not export ioremap_page_range symbol for external module
  mn10300: fix build error of missing fpu_save()
  romfs: use different way to generate fsid for BLOCK or MTD
  frv: add missing atomic64 operations
  mm, page_alloc: fix premature OOM when racing with cpuset mems update
  mm, page_alloc: move cpuset seqcount checking to slowpath
  mm, page_alloc: fix fast-path race with cpuset update or removal
  mm, page_alloc: fix check for NULL preferred_zone
  kernel/panic.c: add missing \n
  fbdev: color map copying bounds checking
  frv: add atomic64_add_unless()
  mm/mempolicy.c: do not put mempolicy before using its nodemask
  radix-tree: fix private list warnings
  Documentation/filesystems/proc.txt: add VmPin
  mm, memcg: do not retry precharge charges
  proc: add a schedule point in proc_pid_readdir()
  mm: alloc_contig: re-allow CMA to compact FS pages
  mm/slub.c: trace free objects at KERN_INFO
  ...

lib/ioremap.c

@@ -144,4 +144,3 @@ int ioremap_page_range(unsigned long addr,
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(ioremap_page_range);

lib/radix-tree.c

@@ -769,7 +769,7 @@ static void radix_tree_free_nodes(struct radix_tree_node *node)
 			struct radix_tree_node *old = child;
 			offset = child->offset + 1;
 			child = child->parent;
-			WARN_ON_ONCE(!list_empty(&node->private_list));
+			WARN_ON_ONCE(!list_empty(&old->private_list));
 			radix_tree_node_free(old);
 			if (old == entry_to_node(node))
 				return;

mm/huge_memory.c

@@ -783,6 +783,12 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
 
 	assert_spin_locked(pmd_lockptr(mm, pmd));
 
+	/*
+	 * When we COW a devmap PMD entry, we split it into PTEs, so we should
+	 * not be in this function with `flags & FOLL_COW` set.
+	 */
+	WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set");
+
 	if (flags & FOLL_WRITE && !pmd_write(*pmd))
 		return NULL;
 
@@ -1128,6 +1134,16 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
 	return ret;
 }
 
+/*
+ * FOLL_FORCE can write to even unwritable pmd's, but only
+ * after we've gone through a COW cycle and they are dirty.
+ */
+static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
+{
+	return pmd_write(pmd) ||
+	       ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd));
+}
+
 struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 				   unsigned long addr,
 				   pmd_t *pmd,
@@ -1138,7 +1154,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 
 	assert_spin_locked(pmd_lockptr(mm, pmd));
 
-	if (flags & FOLL_WRITE && !pmd_write(*pmd))
+	if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags))
 		goto out;
 
 	/* Avoid dumping huge zero page */

mm/memcontrol.c

@@ -4353,9 +4353,9 @@ static int mem_cgroup_do_precharge(unsigned long count)
 		return ret;
 	}
 
-	/* Try charges one by one with reclaim */
+	/* Try charges one by one with reclaim, but do not retry */
 	while (count--) {
-		ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
+		ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
 		if (ret)
 			return ret;
 		mc.precharge++;

mm/memory_hotplug.c

@@ -1033,36 +1033,39 @@ static void node_states_set_node(int node, struct memory_notify *arg)
 	node_set_state(node, N_MEMORY);
 }
 
-int zone_can_shift(unsigned long pfn, unsigned long nr_pages,
-		   enum zone_type target)
+bool zone_can_shift(unsigned long pfn, unsigned long nr_pages,
+		   enum zone_type target, int *zone_shift)
 {
 	struct zone *zone = page_zone(pfn_to_page(pfn));
 	enum zone_type idx = zone_idx(zone);
 	int i;
 
+	*zone_shift = 0;
+
 	if (idx < target) {
 		/* pages must be at end of current zone */
 		if (pfn + nr_pages != zone_end_pfn(zone))
-			return 0;
+			return false;
 
 		/* no zones in use between current zone and target */
 		for (i = idx + 1; i < target; i++)
 			if (zone_is_initialized(zone - idx + i))
-				return 0;
+				return false;
 	}
 
 	if (target < idx) {
 		/* pages must be at beginning of current zone */
 		if (pfn != zone->zone_start_pfn)
-			return 0;
+			return false;
 
 		/* no zones in use between current zone and target */
 		for (i = target + 1; i < idx; i++)
 			if (zone_is_initialized(zone - idx + i))
-				return 0;
+				return false;
 	}
 
-	return target - idx;
+	*zone_shift = target - idx;
+	return true;
 }
 
 /* Must be protected by mem_hotplug_begin() */
@@ -1089,10 +1092,13 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 	    !can_online_high_movable(zone))
 		return -EINVAL;
 
-	if (online_type == MMOP_ONLINE_KERNEL)
-		zone_shift = zone_can_shift(pfn, nr_pages, ZONE_NORMAL);
-	else if (online_type == MMOP_ONLINE_MOVABLE)
-		zone_shift = zone_can_shift(pfn, nr_pages, ZONE_MOVABLE);
+	if (online_type == MMOP_ONLINE_KERNEL) {
+		if (!zone_can_shift(pfn, nr_pages, ZONE_NORMAL, &zone_shift))
+			return -EINVAL;
+	} else if (online_type == MMOP_ONLINE_MOVABLE) {
+		if (!zone_can_shift(pfn, nr_pages, ZONE_MOVABLE, &zone_shift))
+			return -EINVAL;
+	}
 
 	zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
 	if (!zone)

mm/mempolicy.c

@@ -2017,8 +2017,8 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
 
 	nmask = policy_nodemask(gfp, pol);
 	zl = policy_zonelist(gfp, pol, node);
-	mpol_cond_put(pol);
 	page = __alloc_pages_nodemask(gfp, order, zl, nmask);
+	mpol_cond_put(pol);
 out:
 	if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
 		goto retry_cpuset;

mm/page_alloc.c

@@ -3523,12 +3523,13 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 	struct page *page = NULL;
 	unsigned int alloc_flags;
 	unsigned long did_some_progress;
-	enum compact_priority compact_priority = DEF_COMPACT_PRIORITY;
+	enum compact_priority compact_priority;
 	enum compact_result compact_result;
-	int compaction_retries = 0;
-	int no_progress_loops = 0;
+	int compaction_retries;
+	int no_progress_loops;
 	unsigned long alloc_start = jiffies;
 	unsigned int stall_timeout = 10 * HZ;
+	unsigned int cpuset_mems_cookie;
 
 	/*
 	 * In the slowpath, we sanity check order to avoid ever trying to
@@ -3549,6 +3550,23 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 				(__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
 		gfp_mask &= ~__GFP_ATOMIC;
 
+retry_cpuset:
+	compaction_retries = 0;
+	no_progress_loops = 0;
+	compact_priority = DEF_COMPACT_PRIORITY;
+	cpuset_mems_cookie = read_mems_allowed_begin();
+	/*
+	 * We need to recalculate the starting point for the zonelist iterator
+	 * because we might have used different nodemask in the fast path, or
+	 * there was a cpuset modification and we are retrying - otherwise we
+	 * could end up iterating over non-eligible zones endlessly.
+	 */
+	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
+					ac->high_zoneidx, ac->nodemask);
+	if (!ac->preferred_zoneref->zone)
+		goto nopage;
+
+
 	/*
 	 * The fast path uses conservative alloc_flags to succeed only until
 	 * kswapd needs to be woken up, and to avoid the cost of setting up
@@ -3708,6 +3726,13 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 				&compaction_retries))
 		goto retry;
 
+	/*
+	 * It's possible we raced with cpuset update so the OOM would be
+	 * premature (see below the nopage: label for full explanation).
+	 */
+	if (read_mems_allowed_retry(cpuset_mems_cookie))
+		goto retry_cpuset;
+
 	/* Reclaim has failed us, start killing things */
 	page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
 	if (page)
@@ -3720,6 +3745,16 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 	}
 
 nopage:
+	/*
+	 * When updating a task's mems_allowed or mempolicy nodemask, it is
+	 * possible to race with parallel threads in such a way that our
+	 * allocation can fail while the mask is being updated. If we are about
+	 * to fail, check if the cpuset changed during allocation and if so,
+	 * retry.
+	 */
+	if (read_mems_allowed_retry(cpuset_mems_cookie))
+		goto retry_cpuset;
+
 	warn_alloc(gfp_mask,
 			"page allocation failure: order:%u", order);
 got_pg:
@@ -3734,7 +3769,6 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 			struct zonelist *zonelist, nodemask_t *nodemask)
 {
 	struct page *page;
-	unsigned int cpuset_mems_cookie;
 	unsigned int alloc_flags = ALLOC_WMARK_LOW;
 	gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */
 	struct alloc_context ac = {
@@ -3771,9 +3805,6 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 	if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE)
 		alloc_flags |= ALLOC_CMA;
 
-retry_cpuset:
-	cpuset_mems_cookie = read_mems_allowed_begin();
-
 	/* Dirty zone balancing only done in the fast path */
 	ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE);
 
@@ -3784,8 +3815,13 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 	 */
 	ac.preferred_zoneref = first_zones_zonelist(ac.zonelist,
 					ac.high_zoneidx, ac.nodemask);
-	if (!ac.preferred_zoneref) {
+	if (!ac.preferred_zoneref->zone) {
 		page = NULL;
+		/*
+		 * This might be due to race with cpuset_current_mems_allowed
+		 * update, so make sure we retry with original nodemask in the
+		 * slow path.
+		 */
 		goto no_zone;
 	}
 
@@ -3794,6 +3830,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 	if (likely(page))
 		goto out;
 
+no_zone:
 	/*
 	 * Runtime PM, block IO and its error handling path can deadlock
 	 * because I/O on the device might not complete.
@@ -3805,21 +3842,10 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 	 * Restore the original nodemask if it was potentially replaced with
 	 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
 	 */
-	if (cpusets_enabled())
+	if (unlikely(ac.nodemask != nodemask))
 		ac.nodemask = nodemask;
-	page = __alloc_pages_slowpath(alloc_mask, order, &ac);
 
-no_zone:
-	/*
-	 * When updating a task's mems_allowed, it is possible to race with
-	 * parallel threads in such a way that an allocation can fail while
-	 * the mask is being updated. If a page allocation is about to fail,
-	 * check if the cpuset changed during allocation and if so, retry.
-	 */
-	if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) {
-		alloc_mask = gfp_mask;
-		goto retry_cpuset;
-	}
+	page = __alloc_pages_slowpath(alloc_mask, order, &ac);
 
 out:
 	if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
@@ -7248,6 +7274,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 		.zone = page_zone(pfn_to_page(start)),
 		.mode = MIGRATE_SYNC,
 		.ignore_skip_hint = true,
+		.gfp_mask = GFP_KERNEL,
 	};
 	INIT_LIST_HEAD(&cc.migratepages);
 

mm/slub.c

@@ -496,10 +496,11 @@ static inline int check_valid_pointer(struct kmem_cache *s,
 	return 1;
 }
 
-static void print_section(char *text, u8 *addr, unsigned int length)
+static void print_section(char *level, char *text, u8 *addr,
+			  unsigned int length)
 {
 	metadata_access_enable();
-	print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
+	print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
 			length, 1);
 	metadata_access_disable();
 }
@@ -636,14 +637,15 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 	       p, p - addr, get_freepointer(s, p));
 
 	if (s->flags & SLAB_RED_ZONE)
-		print_section("Redzone ", p - s->red_left_pad, s->red_left_pad);
+		print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
+			      s->red_left_pad);
 	else if (p > addr + 16)
-		print_section("Bytes b4 ", p - 16, 16);
+		print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
 
-	print_section("Object ", p, min_t(unsigned long, s->object_size,
-				PAGE_SIZE));
+	print_section(KERN_ERR, "Object ", p,
+		      min_t(unsigned long, s->object_size, PAGE_SIZE));
 	if (s->flags & SLAB_RED_ZONE)
-		print_section("Redzone ", p + s->object_size,
+		print_section(KERN_ERR, "Redzone ", p + s->object_size,
 			s->inuse - s->object_size);
 
 	if (s->offset)
@@ -658,7 +660,8 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 
 	if (off != size_from_object(s))
 		/* Beginning of the filler is the free pointer */
-		print_section("Padding ", p + off, size_from_object(s) - off);
+		print_section(KERN_ERR, "Padding ", p + off,
+			      size_from_object(s) - off);
 
 	dump_stack();
 }
@@ -820,7 +823,7 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
 		end--;
 
 	slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
-	print_section("Padding ", end - remainder, remainder);
+	print_section(KERN_ERR, "Padding ", end - remainder, remainder);
 
 	restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
 	return 0;
@@ -973,7 +976,7 @@ static void trace(struct kmem_cache *s, struct page *page, void *object,
 			page->freelist);
 
 		if (!alloc)
-			print_section("Object ", (void *)object,
+			print_section(KERN_INFO, "Object ", (void *)object,
 					s->object_size);
 
 		dump_stack();