Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - the rest of MM

 - KASAN updates

 - procfs updates

 - exit, fork updates

 - printk updates

 - lib/ updates

 - radix-tree testsuite updates

 - checkpatch updates

 - kprobes updates

 - a few other misc bits

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits)
  samples/kprobes: print out the symbol name for the hooks
  samples/kprobes: add a new module parameter
  kprobes: add the "tls" argument for j_do_fork
  init/main.c: simplify initcall_blacklisted()
  fs/efs/super.c: fix return value
  checkpatch: improve --git <commit-count> shortcut
  checkpatch: reduce number of `git log` calls with --git
  checkpatch: add support to check already applied git commits
  checkpatch: add --list-types to show message types to show or ignore
  checkpatch: advertise the --fix and --fix-inplace options more
  checkpatch: whine about ACCESS_ONCE
  checkpatch: add test for keywords not starting on tabstops
  checkpatch: improve CONSTANT_COMPARISON test for structure members
  checkpatch: add PREFER_IS_ENABLED test
  lib/GCD.c: use binary GCD algorithm instead of Euclidean
  radix-tree: free up the bottom bit of exceptional entries for reuse
  dax: move RADIX_DAX_ definitions to dax.c
  radix-tree: make radix_tree_descend() more useful
  radix-tree: introduce radix_tree_replace_clear_tags()
  radix-tree: tidy up __radix_tree_create()
  ...

Documentation/ABI/testing/sysfs-block-zram

@@ -166,3 +166,12 @@ Description:
 		The mm_stat file is read-only and represents device's mm
 		statistics (orig_data_size, compr_data_size, etc.) in a format
 		similar to block layer statistics file format.
+
+What:		/sys/block/zram<id>/debug_stat
+Date:		July 2016
+Contact:	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+		The debug_stat file is read-only and represents various
+		device's debugging info useful for kernel developers. Its
+		format is not documented intentionally and may change
+		anytime without any notice.

Documentation/blockdev/zram.txt

@@ -59,27 +59,16 @@ num_devices parameter is optional and tells zram how many devices should be
 pre-created. Default: 1.
 
 2) Set max number of compression streams
-	Compression backend may use up to max_comp_streams compression streams,
-	thus allowing up to max_comp_streams concurrent compression operations.
-	By default, compression backend uses single compression stream.
+	Regardless the value passed to this attribute, ZRAM will always
+	allocate multiple compression streams - one per online CPUs - thus
+	allowing several concurrent compression operations. The number of
+	allocated compression streams goes down when some of the CPUs
+	become offline. There is no single-compression-stream mode anymore,
+	unless you are running a UP system or has only 1 CPU online.
 
-	Examples:
-	#show max compression streams number
+	To find out how many streams are currently available:
 	cat /sys/block/zram0/max_comp_streams
 
-	#set max compression streams number to 3
-	echo 3 > /sys/block/zram0/max_comp_streams
-
-Note:
-In order to enable compression backend's multi stream support max_comp_streams
-must be initially set to desired concurrency level before ZRAM device
-initialisation. Once the device initialised as a single stream compression
-backend (max_comp_streams equals to 1), you will see error if you try to change
-the value of max_comp_streams because single stream compression backend
-implemented as a special case by lock overhead issue and does not support
-dynamic max_comp_streams. Only multi stream backend supports dynamic
-max_comp_streams adjustment.
-
 3) Select compression algorithm
 	Using comp_algorithm device attribute one can see available and
 	currently selected (shown in square brackets) compression algorithms,
@@ -183,6 +172,7 @@ mem_limit         RW    the maximum amount of memory ZRAM can use to store
 pages_compacted   RO    the number of pages freed during compaction
                         (available only via zram<id>/mm_stat node)
 compact           WO    trigger memory compaction
+debug_stat        RO    this file is used for zram debugging purposes
 
 WARNING
 =======

Documentation/filesystems/proc.txt

@@ -225,6 +225,7 @@ Table 1-2: Contents of the status files (as of 4.1)
  TracerPid                   PID of process tracing this process (0 if not)
  Uid                         Real, effective, saved set, and  file system UIDs
  Gid                         Real, effective, saved set, and  file system GIDs
+ Umask                       file mode creation mask
  FDSize                      number of file descriptor slots currently allocated
  Groups                      supplementary group list
  NStgid                      descendant namespace thread group ID hierarchy

Documentation/vm/transhuge.txt

@@ -340,7 +340,7 @@ unaffected. libhugetlbfs will also work fine as usual.
 
 == Graceful fallback ==
 
-Code walking pagetables but unware about huge pmds can simply call
+Code walking pagetables but unaware about huge pmds can simply call
 split_huge_pmd(vma, pmd, addr) where the pmd is the one returned by
 pmd_offset. It's trivial to make the code transparent hugepage aware
 by just grepping for "pmd_offset" and adding split_huge_pmd where
@@ -414,7 +414,7 @@ tracking. The alternative is alter ->_mapcount in all subpages on each
 map/unmap of the whole compound page.
 
 We set PG_double_map when a PMD of the page got split for the first time,
-but still have PMD mapping. The addtional references go away with last
+but still have PMD mapping. The additional references go away with last
 compound_mapcount.
 
 split_huge_page internally has to distribute the refcounts in the head
@@ -432,10 +432,10 @@ page->_mapcount.
 We safe against physical memory scanners too: the only legitimate way
 scanner can get reference to a page is get_page_unless_zero().
 
-All tail pages has zero ->_refcount until atomic_add(). It prevent scanner
-from geting reference to tail page up to the point. After the atomic_add()
-we don't care about ->_refcount value.  We already known how many references
-with should uncharge from head page.
+All tail pages have zero ->_refcount until atomic_add(). This prevents the
+scanner from getting a reference to the tail page up to that point. After the
+atomic_add() we don't care about the ->_refcount value.  We already known how
+many references should be uncharged from the head page.
 
 For head page get_page_unless_zero() will succeed and we don't mind. It's
 clear where reference should go after split: it will stay on head page.

Documentation/vm/z3fold.txt

@@ -0,0 +1,26 @@
+z3fold
+------
+
+z3fold is a special purpose allocator for storing compressed pages.
+It is designed to store up to three compressed pages per physical page.
+It is a zbud derivative which allows for higher compression
+ratio keeping the simplicity and determinism of its predecessor.
+
+The main differences between z3fold and zbud are:
+* unlike zbud, z3fold allows for up to PAGE_SIZE allocations
+* z3fold can hold up to 3 compressed pages in its page
+* z3fold doesn't export any API itself and is thus intended to be used
+  via the zpool API.
+
+To keep the determinism and simplicity, z3fold, just like zbud, always
+stores an integral number of compressed pages per page, but it can store
+up to 3 pages unlike zbud which can store at most 2. Therefore the
+compression ratio goes to around 2.7x while zbud's one is around 1.7x.
+
+Unlike zbud (but like zsmalloc for that matter) z3fold_alloc() does not
+return a dereferenceable pointer. Instead, it returns an unsigned long
+handle which encodes actual location of the allocated object.
+
+Keeping effective compression ratio close to zsmalloc's, z3fold doesn't
+depend on MMU enabled and provides more predictable reclaim behavior
+which makes it a better fit for small and response-critical systems.

MAINTAINERS

@@ -6264,7 +6264,7 @@ S:	Maintained
 F:	arch/*/include/asm/kasan.h
 F:	arch/*/mm/kasan_init*
 F:	Documentation/kasan.txt
-F:	include/linux/kasan.h
+F:	include/linux/kasan*.h
 F:	lib/test_kasan.c
 F:	mm/kasan/
 F:	scripts/Makefile.kasan
@@ -8280,7 +8280,6 @@ F:	drivers/of/resolver.c
 OPENRISC ARCHITECTURE
 M:	Jonas Bonn <jonas@southpole.se>
 W:	http://openrisc.net
-L:	linux@lists.openrisc.net (moderated for non-subscribers)
 S:	Maintained
 T:	git git://openrisc.net/~jonas/linux
 F:	arch/openrisc/
@@ -8401,7 +8400,6 @@ F:	drivers/platform/x86/panasonic-laptop.c
 
 PANASONIC MN10300/AM33/AM34 PORT
 M:	David Howells <dhowells@redhat.com>
-M:	Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
 L:	linux-am33-list@redhat.com (moderated for non-subscribers)
 W:	ftp://ftp.redhat.com/pub/redhat/gnupro/AM33/
 S:	Maintained
@@ -8835,7 +8833,6 @@ F:	drivers/pinctrl/pinctrl-single.c
 
 PIN CONTROLLER - ST SPEAR
 M:	Viresh Kumar <vireshk@kernel.org>
-L:	spear-devel@list.st.com
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 W:	http://www.st.com/spear
 S:	Maintained
@@ -10040,7 +10037,6 @@ F:	drivers/mmc/host/sdhci-s3c*
 
 SECURE DIGITAL HOST CONTROLLER INTERFACE (SDHCI) ST SPEAR DRIVER
 M:	Viresh Kumar <vireshk@kernel.org>
-L:	spear-devel@list.st.com
 L:	linux-mmc@vger.kernel.org
 S:	Maintained
 F:	drivers/mmc/host/sdhci-spear.c
@@ -10603,7 +10599,6 @@ F:	include/linux/compiler.h
 SPEAR PLATFORM SUPPORT
 M:	Viresh Kumar <vireshk@kernel.org>
 M:	Shiraz Hashim <shiraz.linux.kernel@gmail.com>
-L:	spear-devel@list.st.com
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 W:	http://www.st.com/spear
 S:	Maintained
@@ -10612,7 +10607,6 @@ F:	arch/arm/mach-spear/
 
 SPEAR CLOCK FRAMEWORK SUPPORT
 M:	Viresh Kumar <vireshk@kernel.org>
-L:	spear-devel@list.st.com
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 W:	http://www.st.com/spear
 S:	Maintained

arch/Kconfig

@@ -187,7 +187,11 @@ config HAVE_OPTPROBES
 config HAVE_KPROBES_ON_FTRACE
 	bool
 
+config HAVE_NMI
+	bool
+
 config HAVE_NMI_WATCHDOG
+	depends on HAVE_NMI
 	bool
 #
 # An arch should select this if it provides all these things:
@@ -517,6 +521,11 @@ config HAVE_ARCH_MMAP_RND_BITS
 	  - ARCH_MMAP_RND_BITS_MIN
 	  - ARCH_MMAP_RND_BITS_MAX
 
+config HAVE_EXIT_THREAD
+	bool
+	help
+	  An architecture implements exit_thread.
+
 config ARCH_MMAP_RND_BITS_MIN
 	int
 
@@ -638,4 +647,7 @@ config COMPAT_OLD_SIGACTION
 config ARCH_NO_COHERENT_DMA_MMAP
 	bool
 
+config CPU_NO_EFFICIENT_FFS
+	def_bool n
+
 source "kernel/gcov/Kconfig"

arch/alpha/Kconfig

@@ -26,6 +26,7 @@ config ALPHA
 	select MODULES_USE_ELF_RELA
 	select ODD_RT_SIGACTION
 	select OLD_SIGSUSPEND
+	select CPU_NO_EFFICIENT_FFS if !ALPHA_EV67
 	help
 	  The Alpha is a 64-bit general-purpose processor designed and
 	  marketed by the Digital Equipment Corporation of blessed memory,

arch/alpha/kernel/process.c

@@ -210,14 +210,6 @@ start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
 }
 EXPORT_SYMBOL(start_thread);
 
-/*
- * Free current thread data structures etc..
- */
-void
-exit_thread(void)
-{
-}
-
 void
 flush_thread(void)
 {

arch/arc/Kconfig

@@ -107,6 +107,7 @@ choice
 
 config ISA_ARCOMPACT
 	bool "ARCompact ISA"
+	select CPU_NO_EFFICIENT_FFS
 	help
 	  The original ARC ISA of ARC600/700 cores
 

arch/arc/kernel/process.c

@@ -183,13 +183,6 @@ void flush_thread(void)
 {
 }
 
-/*
- * Free any architecture-specific thread data structures, etc.
- */
-void exit_thread(void)
-{
-}
-
 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 {
 	return 0;

arch/arm/Kconfig

@@ -50,6 +50,7 @@ config ARM
 	select HAVE_DMA_CONTIGUOUS if MMU
 	select HAVE_DYNAMIC_FTRACE if (!XIP_KERNEL) && !CPU_ENDIAN_BE32 && MMU
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
+	select HAVE_EXIT_THREAD
 	select HAVE_FTRACE_MCOUNT_RECORD if (!XIP_KERNEL)
 	select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL)
 	select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
@@ -66,6 +67,7 @@ config ARM
 	select HAVE_KRETPROBES if (HAVE_KPROBES)
 	select HAVE_MEMBLOCK
 	select HAVE_MOD_ARCH_SPECIFIC
+	select HAVE_NMI
 	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
 	select HAVE_OPTPROBES if !THUMB2_KERNEL
 	select HAVE_PERF_EVENTS

arch/arm/kernel/process.c

@@ -193,9 +193,9 @@ EXPORT_SYMBOL_GPL(thread_notify_head);
 /*
  * Free current thread data structures etc..
  */
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
 {
-	thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
+	thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
 }
 
 void flush_thread(void)

arch/arm/kernel/smp.c

@@ -644,9 +644,11 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 		break;
 
 	case IPI_CPU_BACKTRACE:
+		printk_nmi_enter();
 		irq_enter();
 		nmi_cpu_backtrace(regs);
 		irq_exit();
+		printk_nmi_exit();
 		break;
 
 	default:

arch/arm/mm/Kconfig

@@ -421,18 +421,21 @@ config CPU_32v3
 	select CPU_USE_DOMAINS if MMU
 	select NEED_KUSER_HELPERS
 	select TLS_REG_EMUL if SMP || !MMU
+	select CPU_NO_EFFICIENT_FFS
 
 config CPU_32v4
 	bool
 	select CPU_USE_DOMAINS if MMU
 	select NEED_KUSER_HELPERS
 	select TLS_REG_EMUL if SMP || !MMU
+	select CPU_NO_EFFICIENT_FFS
 
 config CPU_32v4T
 	bool
 	select CPU_USE_DOMAINS if MMU
 	select NEED_KUSER_HELPERS
 	select TLS_REG_EMUL if SMP || !MMU
+	select CPU_NO_EFFICIENT_FFS
 
 config CPU_32v5
 	bool

arch/arm/vfp/vfpmodule.c

@@ -156,10 +156,6 @@ static void vfp_thread_copy(struct thread_info *thread)
  *   - we could be preempted if tree preempt rcu is enabled, so
  *	it is unsafe to use thread->cpu.
  *  THREAD_NOTIFY_EXIT
- *   - the thread (v) will be running on the local CPU, so
- *	v === current_thread_info()
- *   - thread->cpu is the local CPU number at the time it is accessed,
- *	but may change at any time.
  *   - we could be preempted if tree preempt rcu is enabled, so
  *	it is unsafe to use thread->cpu.
  */

arch/arm64/kernel/process.c

@@ -200,13 +200,6 @@ void show_regs(struct pt_regs * regs)
 	__show_regs(regs);
 }
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-}
-
 static void tls_thread_flush(void)
 {
 	asm ("msr tpidr_el0, xzr");

arch/avr32/Kconfig

@@ -4,6 +4,7 @@ config AVR32
 	# that we usually don't need on AVR32.
 	select EXPERT
 	select HAVE_CLK
+	select HAVE_EXIT_THREAD
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
 	select VIRT_TO_BUS
@@ -17,6 +18,7 @@ config AVR32
 	select GENERIC_CLOCKEVENTS
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
+	select HAVE_NMI
 	help
 	  AVR32 is a high-performance 32-bit RISC microprocessor core,
 	  designed for cost-sensitive embedded applications, with particular

arch/avr32/kernel/process.c

@@ -62,9 +62,9 @@ void machine_restart(char *cmd)
 /*
  * Free current thread data structures etc
  */
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
 {
-	ocd_disable(current);
+	ocd_disable(tsk);
 }
 
 void flush_thread(void)

arch/blackfin/Kconfig

@@ -40,6 +40,7 @@ config BLACKFIN
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
 	select HAVE_DEBUG_STACKOVERFLOW
+	select HAVE_NMI
 
 config GENERIC_CSUM
 	def_bool y