Move EXIT_DEAD test in wait_consider_task() above ptrace check.  As
ptraced tasks can't be EXIT_DEAD, this change doesn't cause any
behavior change.  This is to prepare for further changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>

While ptraced, a task may be resumed while the containing process is
still job control stopped.  If the task receives another stop signal
in this state, it will still initiate group stop, which generates
group_exit_code, which the real parent would be able to see once the
ptracer detaches.

In this scenario, the real parent may see two consecutive CLD_STOPPED
events from two stop signals without intervening SIGCONT, which
normally is impossible.

Test case follows.

  #include <stdio.h>
  #include <unistd.h>
  #include <sys/ptrace.h>
  #include <sys/wait.h>

  int main(void)
  {
	  pid_t tracee;
	  siginfo_t si;

	  tracee = fork();
	  if (!tracee)
		  while (1)
			  pause();

	  kill(tracee, SIGSTOP);
	  waitid(P_PID, tracee, &si, WSTOPPED);

	  if (!fork()) {
		  ptrace(PTRACE_ATTACH, tracee, NULL, NULL);
		  waitid(P_PID, tracee, &si, WSTOPPED);
		  ptrace(PTRACE_CONT, tracee, NULL, (void *)(long)si.si_status);
		  waitid(P_PID, tracee, &si, WSTOPPED);
		  ptrace(PTRACE_CONT, tracee, NULL, (void *)(long)si.si_status);
		  waitid(P_PID, tracee, &si, WSTOPPED);
		  ptrace(PTRACE_DETACH, tracee, NULL, NULL);
		  return 0;
	  }

	  while (1) {
		  si.si_pid = 0;
		  waitid(P_PID, tracee, &si, WSTOPPED | WNOHANG);
		  if (si.si_pid)
			  printf("st=%02d c=%02d\n", si.si_status, si.si_code);
	  }
	  return 0;
  }

Before the patch, the latter waitid() in polling mode reports the
second stopped event generated by the implied SIGSTOP of
PTRACE_ATTACH.

  st=19 c=05
  ^C

After the patch, the second event is not reported.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>

Currently, __ptrace_unlink() wakes up the tracee iff it's in
TASK_TRACED.  For unlinking from PTRACE_DETACH, this is correct as the
tracee is guaranteed to be in TASK_TRACED or dead; however, unlinking
also happens when the ptracer exits and in this case the ptracee can
be in any state and ptrace might be left running even if the group it
belongs to is stopped.

This patch updates __ptrace_unlink() such that GROUP_STOP_PENDING is
reinstated regardless of the ptracee's current state as long as it's
alive and makes sure that signal_wake_up() is called if execution
state transition is necessary.

Test case follows.

  #include <unistd.h>
  #include <time.h>
  #include <sys/types.h>
  #include <sys/ptrace.h>
  #include <sys/wait.h>

  static const struct timespec ts1s = { .tv_sec = 1 };

  int main(void)
  {
	  pid_t tracee;
	  siginfo_t si;

	  tracee = fork();
	  if (tracee == 0) {
		  while (1) {
			  nanosleep(&ts1s, NULL);
			  write(1, ".", 1);
		  }
	  }

	  ptrace(PTRACE_ATTACH, tracee, NULL, NULL);
	  waitid(P_PID, tracee, &si, WSTOPPED);
	  ptrace(PTRACE_CONT, tracee, NULL, (void *)(long)si.si_status);
	  waitid(P_PID, tracee, &si, WSTOPPED);
	  ptrace(PTRACE_CONT, tracee, NULL, (void *)(long)si.si_status);
	  write(1, "exiting", 7);
	  return 0;
  }

Before the patch, after the parent process exits, the child is left
running and prints out "." every second.

  exiting..... (continues)

After the patch, the group stop initiated by the implied SIGSTOP from
PTRACE_ATTACH is re-established when the parent exits.

  exiting

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>

Remove the extra task_is_traced() check in __ptrace_unlink() and
collapse ptrace_untrace() into __ptrace_unlink().  This is to prepare
for further changes.

While at it, drop the comment on top of ptrace_untrace() and convert
__ptrace_unlink() comment to docbook format.  Detailed comment will be
added by the next patch.

This patch doesn't cause any visible behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>

Currently, if the task is STOPPED on ptrace attach, it's left alone
and the state is silently changed to TRACED on the next ptrace call.
The behavior breaks the assumption that arch_ptrace_stop() is called
before any task is poked by ptrace and is ugly in that a task
manipulates the state of another task directly.

With GROUP_STOP_PENDING, the transitions between TASK_STOPPED and
TRACED can be made clean.  The tracer can use the flag to tell the
tracee to retry stop on attach and detach.  On retry, the tracee will
enter the desired state in the correct way.  The lower 16bits of
task->group_stop is used to remember the signal number which caused
the last group stop.  This is used while retrying for ptrace attach as
the original group_exit_code could have been consumed with wait(2) by
then.

As the real parent may wait(2) and consume the group_exit_code
anytime, the group_exit_code needs to be saved separately so that it
can be used when switching from regular sleep to ptrace_stop().  This
is recorded in the lower 16bits of task->group_stop.

If a task is already stopped and there's no intervening SIGCONT, a
ptrace request immediately following a successful PTRACE_ATTACH should
always succeed even if the tracer doesn't wait(2) for attach
completion; however, with this change, the tracee might still be
TASK_RUNNING trying to enter TASK_TRACED which would cause the
following request to fail with -ESRCH.

This intermediate state is hidden from the ptracer by setting
GROUP_STOP_TRAPPING on attach and making ptrace_check_attach() wait
for it to clear on its signal->wait_chldexit.  Completing the
transition or getting killed clears TRAPPING and wakes up the tracer.

Note that the STOPPED -> RUNNING -> TRACED transition is still visible
to other threads which are in the same group as the ptracer and the
reverse transition is visible to all.  Please read the comments for
details.

Oleg:

* Spotted a race condition where a task may retry group stop without
  proper bookkeeping.  Fixed by redoing bookkeeping on retry.

* Spotted that the transition is visible to userland in several
  different ways.  Most are fixed with GROUP_STOP_TRAPPING.  Unhandled
  corner case is documented.

* Pointed out not setting GROUP_STOP_SIGMASK on an already stopped
  task would result in more consistent behavior.

* Pointed out that calling ptrace_stop() from do_signal_stop() in
  TASK_STOPPED can race with group stop start logic and then confuse
  the TRAPPING wait in ptrace_check_attach().  ptrace_stop() is now
  called with TASK_RUNNING.

* Suggested using signal->wait_chldexit instead of bit wait.

* Spotted a race condition between TRACED transition and clearing of
  TRAPPING.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>

A ptraced task would still stop at do_signal_stop() when it's stopping
for stop signals and do_signal_stop() behaves the same whether the
task is ptraced or not.  However, in addition to stopping,
ptrace_stop() also does ptrace specific stuff like calling
architecture specific callbacks, so this behavior makes the code more
fragile and difficult to understand.

This patch makes do_signal_stop() test whether the task is ptraced and
use ptrace_stop() if so.  This renders tracehook_notify_jctl() rather
pointless as the ptrace notification is now handled by ptrace_stop()
regardless of the return value from the tracehook.  It probably is a
good idea to update it.

This doesn't solve the whole problem as tasks already in stopped state
would stay in the regular stop when ptrace attached.  That part will
be handled by the next patch.

Oleg pointed out that this makes a userland-visible change.  Before,
SIGCONT would be able to wake up a task in group stop even if the task
is ptraced if the tracer hasn't issued another ptrace command
afterwards (as the next ptrace commands transitions the state into
TASK_TRACED which ignores SIGCONT wakeups).  With this and the next
patch, SIGCONT may race with the transition into TASK_TRACED and is
ignored if the tracee already entered TASK_TRACED.

Another userland visible change of this and the next patch is that the
ptracee's state would now be TASK_TRACED where it used to be
TASK_STOPPED, which is visible via fs/proc.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>

Currently, ptrace_stop() unconditionally participates in group stop
bookkeeping.  This is unnecessary and inaccurate.  Make it only
participate if the task is trapping for group stop - ie. if @why is
CLD_STOPPED.  As ptrace_stop() currently is not used when trapping for
group stop, this equals to disabling group stop participation from
ptrace_stop().

A visible behavior change is increased likelihood of delayed group
stop completion if the thread group contains one or more ptraced
tasks.

This is to preapre for further cleanup of the interaction between
group stop and ptrace.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>

Currently task->signal->group_stop_count is used to decide whether to
stop for group stop.  However, if there is a task in the group which
is taking a long time to stop, other tasks which are continued by
ptrace would repeatedly stop for the same group stop until the group
stop is complete.

Conversely, if a ptraced task is in TASK_TRACED state, the debugger
won't get notified of group stops which is inconsistent compared to
the ptraced task in any other state.

This patch introduces GROUP_STOP_PENDING which tracks whether a task
is yet to stop for the group stop in progress.  The flag is set when a
group stop starts and cleared when the task stops the first time for
the group stop, and consulted whenever whether the task should
participate in a group stop needs to be determined.  Note that now
tasks in TASK_TRACED also participate in group stop.

This results in the following behavior changes.

* For a single group stop, a ptracer would see at most one stop
  reported.

* A ptracee in TASK_TRACED now also participates in group stop and the
  tracer would get the notification.  However, as a ptraced task could
  be in TASK_STOPPED state or any ptrace trap could consume group
  stop, the notification may still be missing.  These will be
  addressed with further patches.

* A ptracee may start a group stop while one is still in progress if
  the tracer let it continue with stop signal delivery.  Group stop
  code handles this correctly.

Oleg:

* Spotted that a task might skip signal check even when its
  GROUP_STOP_PENDING is set.  Fixed by updating
  recalc_sigpending_tsk() to check GROUP_STOP_PENDING instead of
  group_stop_count.

* Pointed out that task->group_stop should be cleared whenever
  task->signal->group_stop_count is cleared.  Fixed accordingly.

* Pointed out the behavior inconsistency between TASK_TRACED and
  RUNNING and the last behavior change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>

task->signal->group_stop_count is used to track the progress of group
stop.  It's initialized to the number of tasks which need to stop for
group stop to finish and each stopping or trapping task decrements.
However, each task doesn't keep track of whether it decremented the
counter or not and if woken up before the group stop is complete and
stops again, it can decrement the counter multiple times.

Please consider the following example code.

 static void *worker(void *arg)
 {
	 while (1) ;
	 return NULL;
 }

 int main(void)
 {
	 pthread_t thread;
	 pid_t pid;
	 int i;

	 pid = fork();
	 if (!pid) {
		 for (i = 0; i < 5; i++)
			 pthread_create(&thread, NULL, worker, NULL);
		 while (1) ;
		 return 0;
	 }

	 ptrace(PTRACE_ATTACH, pid, NULL, NULL);
	 while (1) {
		 waitid(P_PID, pid, NULL, WSTOPPED);
		 ptrace(PTRACE_SINGLESTEP, pid, NULL, (void *)(long)SIGSTOP);
	 }
	 return 0;
 }

The child creates five threads and the parent continuously traps the
first thread and whenever the child gets a signal, SIGSTOP is
delivered.  If an external process sends SIGSTOP to the child, all
other threads in the process should reliably stop.  However, due to
the above bug, the first thread will often end up consuming
group_stop_count multiple times and SIGSTOP often ends up stopping
none or part of the other four threads.

This patch adds a new field task->group_stop which is protected by
siglock and uses GROUP_STOP_CONSUME flag to track which task is still
to consume group_stop_count to fix this bug.

task_clear_group_stop_pending() and task_participate_group_stop() are
added to help manipulating group stop states.  As ptrace_stop() now
also uses task_participate_group_stop(), it will set
SIGNAL_STOP_STOPPED if it completes a group stop.

There still are many issues regarding the interaction between group
stop and ptrace.  Patches to address them will follow.

- Oleg spotted duplicate GROUP_STOP_CONSUME.  Dropped.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>

To prepare for cleanup of the interaction between group stop and
ptrace, add @why to ptrace_stop().  Existing users are updated such
that there is no behavior change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Roland McGrath <roland@redhat.com>

tracehook_notify_jctl() aids in determining whether and what to report
to the parent when a task is stopped or continued.  The function also
adds an extra requirement that siglock may be released across it,
which is currently unused and quite difficult to satisfy in
well-defined manner.

As job control and the notifications are about to receive major
overhaul, remove the tracehook and open code it.  If ever necessary,
let's factor it out after the overhaul.

* Oleg spotted incorrect CLD_CONTINUED/STOPPED selection when ptraced.
  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>

do_signal_stop() is used only by get_signal_to_deliver() and after a
successful signal stop, it always calls try_to_freeze(), so the
try_to_freeze() loop around schedule() in do_signal_stop() is
superflous and confusing.  Remove it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>

This wake_up_state() has a turbulent history.  This is a remnant from
ancient ptrace implementation and patently wrong.  Commit 95a3540d
(ptrace_detach: the wrong wakeup breaks the ERESTARTxxx logic) removed
it but the change was reverted later by commit edaba2c5

 (ptrace:
revert "ptrace_detach: the wrong wakeup breaks the ERESTARTxxx logic")
citing compatibility breakage and general brokeness of the whole group
stop / ptrace interaction.  Then, recently, it got converted from
wake_up_process() to wake_up_state() to make it less dangerous.

Digging through the mailing archives, the compatibility breakage
doesn't seem to be critical in the sense that the behavior isn't well
defined or reliable to begin with and it seems to have been agreed to
remove the wakeup with proper cleanup of the whole thing.

Now that the group stop and its interaction with ptrace are being
cleaned up, it's high time to finally kill this silliness.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>

After a task receives SIGCONT, its parent is notified via SIGCHLD with
its siginfo describing what the notified event is.  If SIGCONT is
received while the child process is stopped, the code should be
CLD_CONTINUED.  If SIGCONT is recieved while the child process is in
the process of being stopped, it should be CLD_STOPPED.  Which code to
use is determined in prepare_signal() and recorded in signal->flags
using SIGNAL_CLD_CONTINUED|STOP flags.

get_signal_deliver() should test these flags and then notify
accoringly; however, it incorrectly tested SIGNAL_STOP_CONTINUED
instead of SIGNAL_CLD_CONTINUED, thus incorrectly notifying
CLD_CONTINUED if the signal is delivered before the task is wait(2)ed
and CLD_STOPPED if the state was fetched already.

Fix it by testing SIGNAL_CLD_CONTINUED.  While at it, uncompress the
?: test into if/else clause for better readability.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: (66 commits)
  avr32: at32ap700x: fix typo in DMA master configuration
  dmaengine/dmatest: Pass timeout via module params
  dma: let IMX_DMA depend on IMX_HAVE_DMA_V1 instead of an explicit list of SoCs
  fsldma: make halt behave nicely on all supported controllers
  fsldma: reduce locking during descriptor cleanup
  fsldma: support async_tx dependencies and automatic unmapping
  fsldma: fix controller lockups
  fsldma: minor codingstyle and consistency fixes
  fsldma: improve link descriptor debugging
  fsldma: use channel name in printk output
  fsldma: move related helper functions near each other
  dmatest: fix automatic buffer unmap type
  drivers, pch_dma: Fix warning when CONFIG_PM=n.
  dmaengine/dw_dmac fix: use readl & writel instead of __raw_readl & __raw_writel
  avr32: at32ap700x: Specify DMA Flow Controller, Src and Dst msize
  dw_dmac: Setting Default Burst length for transfers as 16.
  dw_dmac: Allow src/dst msize & flow controller to be configured at runtime
  dw_dmac: Changing type of src_master and dest_master to u8.
  dw_dmac: Pass Channel Priority from platform_data
  dw_dmac: Pass Channel Allocation Order from platform_data
  ...

I'm not sure why the read-only data section is excluded from the report,
it seems as relevant as the other data sections (b and d).

I've stripped the symbols starting with __mod_ as they can have their
names dynamically generated and thus comparison between binaries is not
possible.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Andi Kleen <andi@firstfloor.org>
Acked-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Instead of always creating a huge (268K) deflate_workspace with the
maximum compression parameters (windowBits=15, memLevel=8), allow the
caller to obtain a smaller workspace by specifying smaller parameter
values.

For example, when capturing oops and panic reports to a medium with
limited capacity, such as NVRAM, compression may be the only way to
capture the whole report.  In this case, a small workspace (24K works
fine) is a win, whether you allocate the workspace when you need it (i.e.,
during an oops or panic) or at boot time.

I've verified that this patch works with all accepted values of windowBits
(positive and negative), memLevel, and compression level.

Signed-off-by: Jim Keniston <jkenisto@us.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

d_alloc_name return NULL in case error, but we expect errno in
devpts_pty_new.

Addresses http://bugzilla.openvz.org/show_bug.cgi?id=1758



Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The test program below will hang because io_getevents() uses
add_wait_queue_exclusive(), which means the wake_up() in io_destroy() only
wakes up one of the threads.  Fix this by using wake_up_all() in the aio
code paths where we want to make sure no one gets stuck.

	// t.c -- compile with gcc -lpthread -laio t.c

	#include <libaio.h>
	#include <pthread.h>
	#include <stdio.h>
	#include <unistd.h>

	static const int nthr = 2;

	void *getev(void *ctx)
	{
		struct io_event ev;
		io_getevents(ctx, 1, 1, &ev, NULL);
		printf("io_getevents returned\n");
		return NULL;
	}

	int main(int argc, char *argv[])
	{
		io_context_t ctx = 0;
		pthread_t thread[nthr];
		int i;

		io_setup(1024, &ctx);

		for (i = 0; i < nthr; ++i)
			pthread_create(&thread[i], NULL, getev, ctx);

		sleep(1);

		io_destroy(ctx);

		for (i = 0; i < nthr; ++i)
			pthread_join(thread[i], NULL);

		return 0;
	}

Signed-off-by: Roland Dreier <roland@purestorage.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Remove code enabled only when CONFIG_PREEMPT_RT is turned on because it is
not used in the vanilla kernel.

Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ADFS (FileCore) storage complies with the RISC OS filetype specification
(12 bits of file type information is stored in the file load address,
rather than using a file extension).  The existing driver largely ignores
this information and does not present it to the end user.

It is desirable that stored filetypes be made visible to the end user to
facilitate a precise copy of data and metadata from a hard disc (or image
thereof) into a RISC OS emulator (such as RPCEmu) or to a network share
which can be accessed by real Acorn systems.

This patch implements a per-mount filetype suffix option (use -o
ftsuffix=1) to present any filetype as a ,xyz hexadecimal suffix on each
file.  This type suffix is compatible with that used by RISC OS systems
that access network servers using NFS client software and by RPCemu's host
filing system.

Signed-off-by: Stuart Swales <stuart.swales.croftnuisk@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ADFS (FileCore) storage complies with the RISC OS timestamp specification
(40-bit centiseconds since 01 Jan 1900 00:00:00).  It is desirable that
stored timestamp precision be maintained to facilitate a precise copy of
data and metadata from a hard disc (or image thereof) into a RISC OS
emulator (such as RPCEmu).

This patch implements a full-precision conversion from ADFS to Unix
timestamp as the existing driver, for ease of calculation with old 32-bit
compilers, uses the common trick of shifting the 40-bits representing
centiseconds around into 32-bits representing seconds thereby losing
precision.

Signed-off-by: Stuart <Swales&lt;stuart.swales.croftnuisk@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Kernel crashes in fs/adfs module when accessing directories with a large
number of objects on mounted Acorn ADFS E+/F+ format discs (or images) as
the existing code writes off the end of the fixed array of struct
buffer_head pointers.

Additionally, each directory access that didn't crash would leak a buffer
as nr_buffers was not adjusted correctly for E+/F+ discs (was always left
as one less than required).

The patch fixes this by allocating a dynamically-sized set of struct
buffer_head pointers if necessary for the E+/F+ case (many directories
still do in fact fit in 2048 bytes) and sets the correct nr_buffers so
that all buffers are released.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=26072



Tested by tar'ing the contents of my RISC PC's E+ format 20Gb HDD which
contains a number of large directories that previously crashed the kernel.

Signed-off-by: Stuart Swales <stuart.swales.croftnuisk@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

page-types.c doesn't supply a way to specify the debugfs path and the
original debugfs path is not usual on most machines.  This patch supplies
a way to auto mount debugfs if needed.

This patch is heavily inspired by tools/perf/utils/debugfs.c

[akpm@linux-foundation.org: make functions static]
[akpm@linux-foundation.org: fix debugfs_mount() signature]
Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I noticed the 'mcelog' program had no comment and then ended up "fixing"
a few more things:

  * reiserfsck -V does not print "reiserfsprogs" (any more?)
  * is "udevinfo" still shipped? udevd certainly is
  * grub2 doesn't have a 'grub' binary
  * add a "# how to get the mcelog version" comment

Signed-off-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is a missing case for "Chapter 3: Placing Braces and Spaces".  We
often know we should not use braces where a single statement.  The first
case is:

	if (condition)
		action();

Another case is:

	if (condition)
		do_this();
	else
		do_that();

However, I can not find a description of the second case.

Signed-off-by: Harry Wei <harryxiyou@gmail.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When CONFIG_SYSCTL=n, we get the following warning:

fs/coda/sysctl.c:18: warning: `coda_tabl' defined but not used

Fix the warning by making sure coda_table and it's callee function are in
the same context.  Also clean up the code by removing extra #ifdef.

[akpm@linux-foundation.org: remove unneeded stub macros]
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Not all 64-bit systems require ISA-style DMA, so allow it to be
configurable.  x86 utilizes the generic ISA DMA allocator from
kernel/dma.c, so require it only when CONFIG_ISA_DMA_API is enabled.

Disabling CONFIG_ISA_DMA_API is dependent on x86_64 since those machines
do not have ISA slots and benefit the most from disabling the option (and
on CONFIG_EXPERT as required by H.  Peter Anvin).

When disabled, this also avoids declaring claim_dma_lock(),
release_dma_lock(), request_dma(), and free_dma() since those interfaces
will no longer be provided.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The generic floppy disk driver utilizies the interface provided by
CONFIG_ISA_DMA_API, specifically claim_dma_lock(), release_dma_lock(),
request_dma(), and free_dma().  Thus, there's a strict dependency on the
config option and the driver should only be loaded if the kernel supports
ISA-style DMA.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

8237A utilizes the interface provided by CONFIG_ISA_DMA_API, specifically
claim_dma_lock() and release_dma_lock().  Thus, there's a strict
dependency on the config option and the module should only be loaded if
the kernel supports ISA-style DMA.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

IORESOURCE_DMA cannot be assigned without utilizing the interface
provided by CONFIG_ISA_DMA_API, specifically request_dma() and
free_dma().  Thus, there's a strict dependency on the config option and
limits IORESOURCE_DMA only to architectures that support ISA-style DMA.

ia64 is not one of those architectures, so pnp_check_dma() no longer
needs to be special-cased for that architecture.

pnp_assign_resources() will now return -EINVAL if IORESOURCE_DMA is
attempted on such a kernel.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is a platform driver that supports the built-in real-time clock on
Tegra SOCs.

Signed-off-by: Andrew Chew <achew@nvidia.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Wan ZongShun <mcuos.com@gmail.com>
Acked-by: Jon Mayo <jmayo@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Don't allow everybogy to write to NVRAM.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Cc: Andy Sharp <andy.sharp@onstor.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add alarm/wakeup support to rtc isl1208 driver

Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is a general move to replace bus-specific PM ops with dev_pm_ops in
order to facilitate core improvements. Do this conversion for DS1374.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In do_mounts_rd() if memory cannot be allocated, return -ENOMEM.

Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

With GCC-4.6 we get warnings about things being 'set but not used'.

In load_elf_binary() this can happen with reloc_func_desc if ELF_PLAT_INIT
is defined, but doesn't use the reloc_func_desc argument.

Quiet the warning/error by marking reloc_func_desc as __maybe_unused.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add a comment to ep_poll(), rename labels a bit clearly, fix a warning of
unused variable from gcc and optimize the non-blocking path a little.

Hinted-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>

hannes@cmpxchg.org:

: The non-blocking ep_poll path optimization introduced skipping over the
: return value setup.
:
: Initialize it properly, my userspace gets upset by epoll_wait() returning
: random things.
:
: In addition, remove the reinitialization at the fetch_events label, the
: return value is garuanteed to be zero when execution reaches there.

[hannes@cmpxchg.org: fix initialization]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shawn Bohrer <shawn.bohrer@gmail.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Move the event readiness check into a proper inline, and use it uniformly
inside ep_poll() code.  Events in the ->ovflist are no less ready than the
ones in ->rdllist.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Shawn Bohrer <shawn.bohrer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add brackets around typecasted argument in crc32() macro.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>