Merge branch 'akpm' (patches from Andrew)

Merge yet more updates from Andrew Morton:
 "This is the post-linux-next queue. Material which was based on or
  dependent upon material which was in -next.

  69 patches.

  Subsystems affected by this patch series: mm (migration and zsmalloc),
  sysctl, proc, and lib"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (69 commits)
  mm: hide the FRONTSWAP Kconfig symbol
  frontswap: remove support for multiple ops
  mm: mark swap_lock and swap_active_head static
  frontswap: simplify frontswap_register_ops
  frontswap: remove frontswap_test
  mm: simplify try_to_unuse
  frontswap: remove the frontswap exports
  frontswap: simplify frontswap_init
  frontswap: remove frontswap_curr_pages
  frontswap: remove frontswap_shrink
  frontswap: remove frontswap_tmem_exclusive_gets
  frontswap: remove frontswap_writethrough
  mm: remove cleancache
  lib/stackdepot: always do filter_irq_stacks() in stack_depot_save()
  lib/stackdepot: allow optional init and stack_table allocation by kvmalloc()
  proc: remove PDE_DATA() completely
  fs: proc: store PDE()->data into inode->i_private
  zsmalloc: replace get_cpu_var with local_lock
  zsmalloc: replace per zpage lock with pool->migrate_lock
  locking/rwlocks: introduce write_lock_nested
  ...

4 files changed, 47 insertions, 27 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index c20b68ad2bc3..51c368a50b16 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -673,6 +673,10 @@ config STACKDEPOT
 	bool
 	select STACKTRACE
 
+config STACKDEPOT_ALWAYS_INIT
+	bool
+	select STACKDEPOT
+
 config STACK_HASH_ORDER
 	int "stack depot hash size (12 => 4KB, 20 => 1024KB)"
 	range 12 20
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index cdc842d090db..879757b6dd14 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -38,7 +38,7 @@ menuconfig KASAN
 		    CC_HAS_WORKING_NOSANITIZE_ADDRESS) || \
 		   HAVE_ARCH_KASAN_HW_TAGS
 	depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
-	select STACKDEPOT
+	select STACKDEPOT_ALWAYS_INIT
 	help
 	  Enables KASAN (KernelAddressSANitizer) - runtime memory debugger,
 	  designed to find out-of-bounds accesses and use-after-free bugs.
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index b437ae79aca1..bf5ba9af0500 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -23,6 +23,7 @@
 #include <linux/jhash.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/mutex.h>
 #include <linux/percpu.h>
 #include <linux/printk.h>
 #include <linux/slab.h>
@@ -161,18 +162,40 @@ static int __init is_stack_depot_disabled(char *str)
 }
 early_param("stack_depot_disable", is_stack_depot_disabled);
 
-int __init stack_depot_init(void)
+/*
+ * __ref because of memblock_alloc(), which will not be actually called after
+ * the __init code is gone, because at that point slab_is_available() is true
+ */
+__ref int stack_depot_init(void)
 {
-	if (!stack_depot_disable) {
+	static DEFINE_MUTEX(stack_depot_init_mutex);
+
+	mutex_lock(&stack_depot_init_mutex);
+	if (!stack_depot_disable && !stack_table) {
 		size_t size = (STACK_HASH_SIZE * sizeof(struct stack_record *));
 		int i;
 
-		stack_table = memblock_alloc(size, size);
-		for (i = 0; i < STACK_HASH_SIZE;  i++)
-			stack_table[i] = NULL;
+		if (slab_is_available()) {
+			pr_info("Stack Depot allocating hash table with kvmalloc\n");
+			stack_table = kvmalloc(size, GFP_KERNEL);
+		} else {
+			pr_info("Stack Depot allocating hash table with memblock_alloc\n");
+			stack_table = memblock_alloc(size, SMP_CACHE_BYTES);
+		}
+		if (stack_table) {
+			for (i = 0; i < STACK_HASH_SIZE;  i++)
+				stack_table[i] = NULL;
+		} else {
+			pr_err("Stack Depot hash table allocation failed, disabling\n");
+			stack_depot_disable = true;
+			mutex_unlock(&stack_depot_init_mutex);
+			return -ENOMEM;
+		}
 	}
+	mutex_unlock(&stack_depot_init_mutex);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(stack_depot_init);
 
 /* Calculate hash for a stack */
 static inline u32 hash_stack(unsigned long *entries, unsigned int size)
@@ -305,6 +328,9 @@ EXPORT_SYMBOL_GPL(stack_depot_fetch);
  * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids
  * any allocations and will fail if no space is left to store the stack trace.
  *
+ * If the stack trace in @entries is from an interrupt, only the portion up to
+ * interrupt entry is saved.
+ *
  * Context: Any context, but setting @can_alloc to %false is required if
  *          alloc_pages() cannot be used from the current context. Currently
  *          this is the case from contexts where neither %GFP_ATOMIC nor
@@ -323,6 +349,16 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries,
 	unsigned long flags;
 	u32 hash;
 
+	/*
+	 * If this stack trace is from an interrupt, including anything before
+	 * interrupt entry usually leads to unbounded stackdepot growth.
+	 *
+	 * Because use of filter_irq_stacks() is a requirement to ensure
+	 * stackdepot can efficiently deduplicate interrupt stacks, always
+	 * filter_irq_stacks() to simplify all callers' use of stackdepot.
+	 */
+	nr_entries = filter_irq_stacks(entries, nr_entries);
+
 	if (unlikely(nr_entries == 0) || stack_depot_disable)
 		goto fast_exit;
 
diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
index 3750323973f4..a5a3d6c27e1f 100644
--- a/lib/test_sysctl.c
+++ b/lib/test_sysctl.c
@@ -128,26 +128,6 @@ static struct ctl_table test_table[] = {
 	{ }
 };
 
-static struct ctl_table test_sysctl_table[] = {
-	{
-		.procname	= "test_sysctl",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= test_table,
-	},
-	{ }
-};
-
-static struct ctl_table test_sysctl_root_table[] = {
-	{
-		.procname	= "debug",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= test_sysctl_table,
-	},
-	{ }
-};
-
 static struct ctl_table_header *test_sysctl_header;
 
 static int __init test_sysctl_init(void)
@@ -155,7 +135,7 @@ static int __init test_sysctl_init(void)
 	test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
 	if (!test_data.bitmap_0001)
 		return -ENOMEM;
-	test_sysctl_header = register_sysctl_table(test_sysctl_root_table);
+	test_sysctl_header = register_sysctl("debug/test_sysctl", test_table);
 	if (!test_sysctl_header) {
 		kfree(test_data.bitmap_0001);
 		return -ENOMEM;