Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 104 insertions, 44 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a650db29606f..469bbf505f85 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -46,19 +46,84 @@
 static void generic_online_page(struct page *page);
 
 static online_page_callback_t online_page_callback = generic_online_page;
+static DEFINE_MUTEX(online_page_callback_lock);
 
-DEFINE_MUTEX(mem_hotplug_mutex);
+/* The same as the cpu_hotplug lock, but for memory hotplug. */
+static struct {
+	struct task_struct *active_writer;
+	struct mutex lock; /* Synchronizes accesses to refcount, */
+	/*
+	 * Also blocks the new readers during
+	 * an ongoing mem hotplug operation.
+	 */
+	int refcount;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map dep_map;
+#endif
+} mem_hotplug = {
+	.active_writer = NULL,
+	.lock = __MUTEX_INITIALIZER(mem_hotplug.lock),
+	.refcount = 0,
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	.dep_map = {.name = "mem_hotplug.lock" },
+#endif
+};
+
+/* Lockdep annotations for get/put_online_mems() and mem_hotplug_begin/end() */
+#define memhp_lock_acquire_read() lock_map_acquire_read(&mem_hotplug.dep_map)
+#define memhp_lock_acquire()      lock_map_acquire(&mem_hotplug.dep_map)
+#define memhp_lock_release()      lock_map_release(&mem_hotplug.dep_map)
+
+void get_online_mems(void)
+{
+	might_sleep();
+	if (mem_hotplug.active_writer == current)
+		return;
+	memhp_lock_acquire_read();
+	mutex_lock(&mem_hotplug.lock);
+	mem_hotplug.refcount++;
+	mutex_unlock(&mem_hotplug.lock);
+
+}
 
-void lock_memory_hotplug(void)
+void put_online_mems(void)
 {
-	mutex_lock(&mem_hotplug_mutex);
+	if (mem_hotplug.active_writer == current)
+		return;
+	mutex_lock(&mem_hotplug.lock);
+
+	if (WARN_ON(!mem_hotplug.refcount))
+		mem_hotplug.refcount++; /* try to fix things up */
+
+	if (!--mem_hotplug.refcount && unlikely(mem_hotplug.active_writer))
+		wake_up_process(mem_hotplug.active_writer);
+	mutex_unlock(&mem_hotplug.lock);
+	memhp_lock_release();
+
 }
 
-void unlock_memory_hotplug(void)
+static void mem_hotplug_begin(void)
 {
-	mutex_unlock(&mem_hotplug_mutex);
+	mem_hotplug.active_writer = current;
+
+	memhp_lock_acquire();
+	for (;;) {
+		mutex_lock(&mem_hotplug.lock);
+		if (likely(!mem_hotplug.refcount))
+			break;
+		__set_current_state(TASK_UNINTERRUPTIBLE);
+		mutex_unlock(&mem_hotplug.lock);
+		schedule();
+	}
 }
 
+static void mem_hotplug_done(void)
+{
+	mem_hotplug.active_writer = NULL;
+	mutex_unlock(&mem_hotplug.lock);
+	memhp_lock_release();
+}
 
 /* add this memory to iomem resource */
 static struct resource *register_memory_resource(u64 start, u64 size)
@@ -727,14 +792,16 @@ int set_online_page_callback(online_page_callback_t callback)
 {
 	int rc = -EINVAL;
 
-	lock_memory_hotplug();
+	get_online_mems();
+	mutex_lock(&online_page_callback_lock);
 
 	if (online_page_callback == generic_online_page) {
 		online_page_callback = callback;
 		rc = 0;
 	}
 
-	unlock_memory_hotplug();
+	mutex_unlock(&online_page_callback_lock);
+	put_online_mems();
 
 	return rc;
 }
@@ -744,14 +811,16 @@ int restore_online_page_callback(online_page_callback_t callback)
 {
 	int rc = -EINVAL;
 
-	lock_memory_hotplug();
+	get_online_mems();
+	mutex_lock(&online_page_callback_lock);
 
 	if (online_page_callback == callback) {
 		online_page_callback = generic_online_page;
 		rc = 0;
 	}
 
-	unlock_memory_hotplug();
+	mutex_unlock(&online_page_callback_lock);
+	put_online_mems();
 
 	return rc;
 }
@@ -899,7 +968,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 	int ret;
 	struct memory_notify arg;
 
-	lock_memory_hotplug();
+	mem_hotplug_begin();
 	/*
 	 * This doesn't need a lock to do pfn_to_page().
 	 * The section can't be removed here because of the
@@ -907,23 +976,18 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 	 */
 	zone = page_zone(pfn_to_page(pfn));
 
+	ret = -EINVAL;
 	if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
-	    !can_online_high_movable(zone)) {
-		unlock_memory_hotplug();
-		return -EINVAL;
-	}
+	    !can_online_high_movable(zone))
+		goto out;
 
 	if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
-		if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
-			unlock_memory_hotplug();
-			return -EINVAL;
-		}
+		if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages))
+			goto out;
 	}
 	if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
-		if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
-			unlock_memory_hotplug();
-			return -EINVAL;
-		}
+		if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages))
+			goto out;
 	}
 
 	/* Previous code may changed the zone of the pfn range */
@@ -939,8 +1003,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 	ret = notifier_to_errno(ret);
 	if (ret) {
 		memory_notify(MEM_CANCEL_ONLINE, &arg);
-		unlock_memory_hotplug();
-		return ret;
+		goto out;
 	}
 	/*
 	 * If this zone is not populated, then it is not in zonelist.
@@ -964,8 +1027,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 		       (((unsigned long long) pfn + nr_pages)
 			    << PAGE_SHIFT) - 1);
 		memory_notify(MEM_CANCEL_ONLINE, &arg);
-		unlock_memory_hotplug();
-		return ret;
+		goto out;
 	}
 
 	zone->present_pages += onlined_pages;
@@ -995,9 +1057,9 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 
 	if (onlined_pages)
 		memory_notify(MEM_ONLINE, &arg);
-	unlock_memory_hotplug();
-
-	return 0;
+out:
+	mem_hotplug_done();
+	return ret;
 }
 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 
@@ -1007,7 +1069,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
 	struct pglist_data *pgdat;
 	unsigned long zones_size[MAX_NR_ZONES] = {0};
 	unsigned long zholes_size[MAX_NR_ZONES] = {0};
-	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long start_pfn = PFN_DOWN(start);
 
 	pgdat = NODE_DATA(nid);
 	if (!pgdat) {
@@ -1055,7 +1117,7 @@ int try_online_node(int nid)
 	if (node_online(nid))
 		return 0;
 
-	lock_memory_hotplug();
+	mem_hotplug_begin();
 	pgdat = hotadd_new_pgdat(nid, 0);
 	if (!pgdat) {
 		pr_err("Cannot online node %d due to NULL pgdat\n", nid);
@@ -1073,13 +1135,13 @@ int try_online_node(int nid)
 	}
 
 out:
-	unlock_memory_hotplug();
+	mem_hotplug_done();
 	return ret;
 }
 
 static int check_hotplug_memory_range(u64 start, u64 size)
 {
-	u64 start_pfn = start >> PAGE_SHIFT;
+	u64 start_pfn = PFN_DOWN(start);
 	u64 nr_pages = size >> PAGE_SHIFT;
 
 	/* Memory range must be aligned with section */
@@ -1117,7 +1179,7 @@ int __ref add_memory(int nid, u64 start, u64 size)
 		new_pgdat = !p;
 	}
 
-	lock_memory_hotplug();
+	mem_hotplug_begin();
 
 	new_node = !node_online(nid);
 	if (new_node) {
@@ -1158,7 +1220,7 @@ error:
 	release_memory_resource(res);
 
 out:
-	unlock_memory_hotplug();
+	mem_hotplug_done();
 	return ret;
 }
 EXPORT_SYMBOL_GPL(add_memory);
@@ -1332,7 +1394,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 		 * alloc_migrate_target should be improooooved!!
 		 * migrate_pages returns # of failed pages.
 		 */
-		ret = migrate_pages(&source, alloc_migrate_target, 0,
+		ret = migrate_pages(&source, alloc_migrate_target, NULL, 0,
 					MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
 		if (ret)
 			putback_movable_pages(&source);
@@ -1565,7 +1627,7 @@ static int __ref __offline_pages(unsigned long start_pfn,
 	if (!test_pages_in_a_zone(start_pfn, end_pfn))
 		return -EINVAL;
 
-	lock_memory_hotplug();
+	mem_hotplug_begin();
 
 	zone = page_zone(pfn_to_page(start_pfn));
 	node = zone_to_nid(zone);
@@ -1672,7 +1734,7 @@ repeat:
 	writeback_set_ratelimit();
 
 	memory_notify(MEM_OFFLINE, &arg);
-	unlock_memory_hotplug();
+	mem_hotplug_done();
 	return 0;
 
 failed_removal:
@@ -1684,7 +1746,7 @@ failed_removal:
 	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
 
 out:
-	unlock_memory_hotplug();
+	mem_hotplug_done();
 	return ret;
 }
 
@@ -1888,7 +1950,7 @@ void __ref remove_memory(int nid, u64 start, u64 size)
 
 	BUG_ON(check_hotplug_memory_range(start, size));
 
-	lock_memory_hotplug();
+	mem_hotplug_begin();
 
 	/*
 	 * All memory blocks must be offlined before removing memory.  Check
@@ -1897,10 +1959,8 @@ void __ref remove_memory(int nid, u64 start, u64 size)
 	 */
 	ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
 				check_memblock_offlined_cb);
-	if (ret) {
-		unlock_memory_hotplug();
+	if (ret)
 		BUG();
-	}
 
 	/* remove memmap entry */
 	firmware_map_remove(start, start + size, "System RAM");
@@ -1909,7 +1969,7 @@ void __ref remove_memory(int nid, u64 start, u64 size)
 
 	try_offline_node(nid);
 
-	unlock_memory_hotplug();
+	mem_hotplug_done();
 }
 EXPORT_SYMBOL_GPL(remove_memory);
 #endif /* CONFIG_MEMORY_HOTREMOVE */