Merge branch 'akpm' (aka "Andrew's patch-bomb")

Andrew elucidates:
 - First installmeant of MM.  We have a HUGE number of MM patches this
   time.  It's crazy.
 - MAINTAINERS updates
 - backlight updates
 - leds
 - checkpatch updates
 - misc ELF stuff
 - rtc updates
 - reiserfs
 - procfs
 - some misc other bits

* akpm: (124 commits)
  user namespace: make signal.c respect user namespaces
  workqueue: make alloc_workqueue() take printf fmt and args for name
  procfs: add hidepid= and gid= mount options
  procfs: parse mount options
  procfs: introduce the /proc/<pid>/map_files/ directory
  procfs: make proc_get_link to use dentry instead of inode
  signal: add block_sigmask() for adding sigmask to current->blocked
  sparc: make SA_NOMASK a synonym of SA_NODEFER
  reiserfs: don't lock root inode searching
  reiserfs: don't lock journal_init()
  reiserfs: delay reiserfs lock until journal initialization
  reiserfs: delete comments referring to the BKL
  drivers/rtc/interface.c: fix alarm rollover when day or month is out-of-range
  drivers/rtc/rtc-twl.c: add DT support for RTC inside twl4030/twl6030
  drivers/rtc/: remove redundant spi driver bus initialization
  drivers/rtc/rtc-jz4740.c: make jz4740_rtc_driver static
  drivers/rtc/rtc-mc13xxx.c: make mc13xxx_rtc_idtable static
  rtc: convert drivers/rtc/* to use module_platform_driver()
  drivers/rtc/rtc-wm831x.c: convert to devm_kzalloc()
  drivers/rtc/rtc-wm831x.c: remove unused period IRQ handler
  ...

Documentation/ABI/testing/sysfs-class-rtc-rtc0-device-rtc_calibration

@@ -0,0 +1,12 @@
+What:           Attribute for calibrating ST-Ericsson AB8500 Real Time Clock
+Date:           Oct 2011
+KernelVersion:  3.0
+Contact:        Mark Godfrey <[email protected]>
+Description:    The rtc_calibration attribute allows the userspace to
+                calibrate the AB8500.s 32KHz Real Time Clock.
+                Every 60 seconds the AB8500 will correct the RTC's value
+                by adding to it the value of this attribute.
+                The range of the attribute is -127 to +127 in units of
+                30.5 micro-seconds (half-parts-per-million of the 32KHz clock)
+Users:          The /vendor/st-ericsson/base_utilities/core/rtc_calibration
+                daemon uses this interface.

Documentation/devicetree/bindings/rtc/twl-rtc.txt

@@ -0,0 +1,12 @@
+* TI twl RTC
+
+The TWL family (twl4030/6030) contains a RTC.
+
+Required properties:
+- compatible : Should be twl4030-rtc
+
+Examples:
+
+rtc@0 {
+    compatible = "ti,twl4030-rtc";
+};

Documentation/filesystems/proc.txt

@@ -41,6 +41,8 @@ Table of Contents
   3.5	/proc/<pid>/mountinfo - Information about mounts
   3.6	/proc/<pid>/comm  & /proc/<pid>/task/<tid>/comm
 
+  4	Configuring procfs
+  4.1	Mount options
 
 ------------------------------------------------------------------------------
 Preface
@@ -1542,3 +1544,40 @@ a task to set its own or one of its thread siblings comm value. The comm value
 is limited in size compared to the cmdline value, so writing anything longer
 then the kernel's TASK_COMM_LEN (currently 16 chars) will result in a truncated
 comm value.
+
+
+------------------------------------------------------------------------------
+Configuring procfs
+------------------------------------------------------------------------------
+
+4.1	Mount options
+---------------------
+
+The following mount options are supported:
+
+	hidepid=	Set /proc/<pid>/ access mode.
+	gid=		Set the group authorized to learn processes information.
+
+hidepid=0 means classic mode - everybody may access all /proc/<pid>/ directories
+(default).
+
+hidepid=1 means users may not access any /proc/<pid>/ directories but their
+own.  Sensitive files like cmdline, sched*, status are now protected against
+other users.  This makes it impossible to learn whether any user runs
+specific program (given the program doesn't reveal itself by its behaviour).
+As an additional bonus, as /proc/<pid>/cmdline is unaccessible for other users,
+poorly written programs passing sensitive information via program arguments are
+now protected against local eavesdroppers.
+
+hidepid=2 means hidepid=1 plus all /proc/<pid>/ will be fully invisible to other
+users.  It doesn't mean that it hides a fact whether a process with a specific
+pid value exists (it can be learned by other means, e.g. by "kill -0 $PID"),
+but it hides process' uid and gid, which may be learned by stat()'ing
+/proc/<pid>/ otherwise.  It greatly complicates an intruder's task of gathering
+information about running processes, whether some daemon runs with elevated
+privileges, whether other user runs some sensitive program, whether other users
+run any program at all, etc.
+
+gid= defines a group authorized to learn processes information otherwise
+prohibited by hidepid=.  If you use some daemon like identd which needs to learn
+information about processes information, just add identd to this group.

Documentation/kernel-parameters.txt

@@ -628,6 +628,25 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	no_debug_objects
 			[KNL] Disable object debugging
 
+	debug_guardpage_minorder=
+			[KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
+			parameter allows control of the order of pages that will
+			be intentionally kept free (and hence protected) by the
+			buddy allocator. Bigger value increase the probability
+			of catching random memory corruption, but reduce the
+			amount of memory for normal system use. The maximum
+			possible value is MAX_ORDER/2.  Setting this parameter
+			to 1 or 2 should be enough to identify most random
+			memory corruption problems caused by bugs in kernel or
+			driver code when a CPU writes to (or reads from) a
+			random memory location. Note that there exists a class
+			of memory corruptions problems caused by buggy H/W or
+			F/W or by drivers badly programing DMA (basically when
+			memory is written at bus level and the CPU MMU is
+			bypassed) which are not detectable by
+			CONFIG_DEBUG_PAGEALLOC, hence this option will not help
+			tracking down these problems.
+
 	debugpat	[X86] Enable PAT debugging
 
 	decnet.addr=	[HW,NET]

Documentation/trace/events-kmem.txt

@@ -40,8 +40,8 @@ but the call_site can usually be used to extrapolate that information.
 ==================
 mm_page_alloc		  page=%p pfn=%lu order=%d migratetype=%d gfp_flags=%s
 mm_page_alloc_zone_locked page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
-mm_page_free_direct	  page=%p pfn=%lu order=%d
-mm_pagevec_free		  page=%p pfn=%lu order=%d cold=%d
+mm_page_free		  page=%p pfn=%lu order=%d
+mm_page_free_batched	  page=%p pfn=%lu order=%d cold=%d
 
 These four events deal with page allocation and freeing. mm_page_alloc is
 a simple indicator of page allocator activity. Pages may be allocated from
@@ -53,13 +53,13 @@ amounts of activity imply high activity on the zone->lock. Taking this lock
 impairs performance by disabling interrupts, dirtying cache lines between
 CPUs and serialising many CPUs.
 
-When a page is freed directly by the caller, the mm_page_free_direct event
+When a page is freed directly by the caller, the only mm_page_free event
 is triggered. Significant amounts of activity here could indicate that the
 callers should be batching their activities.
 
-When pages are freed using a pagevec, the mm_pagevec_free is
-triggered. Broadly speaking, pages are taken off the LRU lock in bulk and
-freed in batch with a pagevec. Significant amounts of activity here could
+When pages are freed in batch, the also mm_page_free_batched is triggered.
+Broadly speaking, pages are taken off the LRU lock in bulk and
+freed in batch with a page list. Significant amounts of activity here could
 indicate that the system is under memory pressure and can also indicate
 contention on the zone->lru_lock.
 

Documentation/trace/postprocess/trace-pagealloc-postprocess.pl

@@ -17,8 +17,8 @@
 
 # Tracepoint events
 use constant MM_PAGE_ALLOC		=> 1;
-use constant MM_PAGE_FREE_DIRECT 	=> 2;
-use constant MM_PAGEVEC_FREE		=> 3;
+use constant MM_PAGE_FREE		=> 2;
+use constant MM_PAGE_FREE_BATCHED	=> 3;
 use constant MM_PAGE_PCPU_DRAIN		=> 4;
 use constant MM_PAGE_ALLOC_ZONE_LOCKED	=> 5;
 use constant MM_PAGE_ALLOC_EXTFRAG	=> 6;
@@ -223,10 +223,10 @@ sub process_events {
 		# Perl Switch() sucks majorly
 		if ($tracepoint eq "mm_page_alloc") {
 			$perprocesspid{$process_pid}->{MM_PAGE_ALLOC}++;
-		} elsif ($tracepoint eq "mm_page_free_direct") {
-			$perprocesspid{$process_pid}->{MM_PAGE_FREE_DIRECT}++;
-		} elsif ($tracepoint eq "mm_pagevec_free") {
-			$perprocesspid{$process_pid}->{MM_PAGEVEC_FREE}++;
+		} elsif ($tracepoint eq "mm_page_free") {
+			$perprocesspid{$process_pid}->{MM_PAGE_FREE}++
+		} elsif ($tracepoint eq "mm_page_free_batched") {
+			$perprocesspid{$process_pid}->{MM_PAGE_FREE_BATCHED}++;
 		} elsif ($tracepoint eq "mm_page_pcpu_drain") {
 			$perprocesspid{$process_pid}->{MM_PAGE_PCPU_DRAIN}++;
 			$perprocesspid{$process_pid}->{STATE_PCPU_PAGES_DRAINED}++;
@@ -336,8 +336,8 @@ sub dump_stats {
 			$process_pid,
 			$stats{$process_pid}->{MM_PAGE_ALLOC},
 			$stats{$process_pid}->{MM_PAGE_ALLOC_ZONE_LOCKED},
-			$stats{$process_pid}->{MM_PAGE_FREE_DIRECT},
-			$stats{$process_pid}->{MM_PAGEVEC_FREE},
+			$stats{$process_pid}->{MM_PAGE_FREE},
+			$stats{$process_pid}->{MM_PAGE_FREE_BATCHED},
 			$stats{$process_pid}->{MM_PAGE_PCPU_DRAIN},
 			$stats{$process_pid}->{HIGH_PCPU_DRAINS},
 			$stats{$process_pid}->{HIGH_PCPU_REFILLS},
@@ -364,8 +364,8 @@ ()
 
 		$perprocess{$process}->{MM_PAGE_ALLOC} += $perprocesspid{$process_pid}->{MM_PAGE_ALLOC};
 		$perprocess{$process}->{MM_PAGE_ALLOC_ZONE_LOCKED} += $perprocesspid{$process_pid}->{MM_PAGE_ALLOC_ZONE_LOCKED};
-		$perprocess{$process}->{MM_PAGE_FREE_DIRECT} += $perprocesspid{$process_pid}->{MM_PAGE_FREE_DIRECT};
-		$perprocess{$process}->{MM_PAGEVEC_FREE} += $perprocesspid{$process_pid}->{MM_PAGEVEC_FREE};
+		$perprocess{$process}->{MM_PAGE_FREE} += $perprocesspid{$process_pid}->{MM_PAGE_FREE};
+		$perprocess{$process}->{MM_PAGE_FREE_BATCHED} += $perprocesspid{$process_pid}->{MM_PAGE_FREE_BATCHED};
 		$perprocess{$process}->{MM_PAGE_PCPU_DRAIN} += $perprocesspid{$process_pid}->{MM_PAGE_PCPU_DRAIN};
 		$perprocess{$process}->{HIGH_PCPU_DRAINS} += $perprocesspid{$process_pid}->{HIGH_PCPU_DRAINS};
 		$perprocess{$process}->{HIGH_PCPU_REFILLS} += $perprocesspid{$process_pid}->{HIGH_PCPU_REFILLS};

Documentation/trace/tracepoint-analysis.txt

@@ -93,14 +93,14 @@ By specifying the -a switch and analysing sleep, the system-wide events
 for a duration of time can be examined.
 
  $ perf stat -a \
-	-e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
-	-e kmem:mm_pagevec_free \
+	-e kmem:mm_page_alloc -e kmem:mm_page_free \
+	-e kmem:mm_page_free_batched \
 	sleep 10
  Performance counter stats for 'sleep 10':
 
            9630  kmem:mm_page_alloc
-           2143  kmem:mm_page_free_direct
-           7424  kmem:mm_pagevec_free
+           2143  kmem:mm_page_free
+           7424  kmem:mm_page_free_batched
 
    10.002577764  seconds time elapsed
 
@@ -119,15 +119,15 @@ basis using set_ftrace_pid.
 Events can be activated and tracked for the duration of a process on a local
 basis using PCL such as follows.
 
-  $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
-		 -e kmem:mm_pagevec_free ./hackbench 10
+  $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free \
+		 -e kmem:mm_page_free_batched ./hackbench 10
   Time: 0.909
 
     Performance counter stats for './hackbench 10':
 
           17803  kmem:mm_page_alloc
-          12398  kmem:mm_page_free_direct
-           4827  kmem:mm_pagevec_free
+          12398  kmem:mm_page_free
+           4827  kmem:mm_page_free_batched
 
     0.973913387  seconds time elapsed
 
@@ -146,8 +146,8 @@ to know what the standard deviation is. By and large, this is left to the
 performance analyst to do it by hand. In the event that the discrete event
 occurrences are useful to the performance analyst, then perf can be used.
 
-  $ perf stat --repeat 5 -e kmem:mm_page_alloc -e kmem:mm_page_free_direct
-			-e kmem:mm_pagevec_free ./hackbench 10
+  $ perf stat --repeat 5 -e kmem:mm_page_alloc -e kmem:mm_page_free
+			-e kmem:mm_page_free_batched ./hackbench 10
   Time: 0.890
   Time: 0.895
   Time: 0.915
@@ -157,8 +157,8 @@ occurrences are useful to the performance analyst, then perf can be used.
    Performance counter stats for './hackbench 10' (5 runs):
 
           16630  kmem:mm_page_alloc         ( +-   3.542% )
-          11486  kmem:mm_page_free_direct   ( +-   4.771% )
-           4730  kmem:mm_pagevec_free       ( +-   2.325% )
+          11486  kmem:mm_page_free	    ( +-   4.771% )
+           4730  kmem:mm_page_free_batched  ( +-   2.325% )
 
     0.982653002  seconds time elapsed   ( +-   1.448% )
 
@@ -168,15 +168,15 @@ aggregation of discrete events, then a script would need to be developed.
 Using --repeat, it is also possible to view how events are fluctuating over
 time on a system-wide basis using -a and sleep.
 
-  $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
-		-e kmem:mm_pagevec_free \
+  $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free \
+		-e kmem:mm_page_free_batched \
 		-a --repeat 10 \
 		sleep 1
   Performance counter stats for 'sleep 1' (10 runs):
 
            1066  kmem:mm_page_alloc         ( +-  26.148% )
-            182  kmem:mm_page_free_direct   ( +-   5.464% )
-            890  kmem:mm_pagevec_free       ( +-  30.079% )
+            182  kmem:mm_page_free          ( +-   5.464% )
+            890  kmem:mm_page_free_batched  ( +-  30.079% )
 
     1.002251757  seconds time elapsed   ( +-   0.005% )
 
@@ -220,8 +220,8 @@ were generating events within the kernel. To begin this sort of analysis, the
 data must be recorded. At the time of writing, this required root:
 
   $ perf record -c 1 \
-	-e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
-	-e kmem:mm_pagevec_free \
+	-e kmem:mm_page_alloc -e kmem:mm_page_free \
+	-e kmem:mm_page_free_batched \
 	./hackbench 10
   Time: 0.894
   [ perf record: Captured and wrote 0.733 MB perf.data (~32010 samples) ]
@@ -260,8 +260,8 @@ noticed that X was generating an insane amount of page allocations so let's look
 at it:
 
   $ perf record -c 1 -f \
-		-e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
-		-e kmem:mm_pagevec_free \
+		-e kmem:mm_page_alloc -e kmem:mm_page_free \
+		-e kmem:mm_page_free_batched \
 		-p `pidof X`
 
 This was interrupted after a few seconds and