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Commit Graph

21478 Commits

Author SHA1 Message Date
Paul E. McKenney
a3dc3fb161 rcu: repair code-duplication FIXMEs
Combine the duplicate definitions of ULONG_CMP_GE(), ULONG_CMP_LT(),
and rcu_preempt_depth() into include/linux/rcupdate.h.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-08-20 09:00:13 -07:00
Paul E. McKenney
53d84e004d rcu: permit suppressing current grace period's CPU stall warnings
When using a kernel debugger, a long sojourn in the debugger can get
you lots of RCU CPU stall warnings once you resume.  This might not be
helpful, especially if you are using the system console.  This patch
therefore allows RCU CPU stall warnings to be suppressed, but only for
the duration of the current set of grace periods.

This differs from Jason's original patch in that it adds support for
tiny RCU and preemptible RCU, and uses a slightly different method for
suppressing the RCU CPU stall warning messages.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Jason Wessel <jason.wessel@windriver.com>
2010-08-20 09:00:12 -07:00
Paul E. McKenney
9079fd7c2e rcu: update obsolete rcu_read_lock() comment.
The comment says that blocking is illegal in rcu_read_lock()-style
RCU read-side critical sections, which is no longer entirely true
given preemptible RCU.  This commit provides a fix.

Suggested-by: David Miller <davem@davemloft.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-08-20 09:00:10 -07:00
Paul E. McKenney
a57eb940d1 rcu: Add a TINY_PREEMPT_RCU
Implement a small-memory-footprint uniprocessor-only implementation of
preemptible RCU.  This implementation uses but a single blocked-tasks
list rather than the combinatorial number used per leaf rcu_node by
TREE_PREEMPT_RCU, which reduces memory consumption and greatly simplifies
processing.  This version also takes advantage of uniprocessor execution
to accelerate grace periods in the case where there are no readers.

The general design is otherwise broadly similar to that of TREE_PREEMPT_RCU.

This implementation is a step towards having RCU implementation driven
off of the SMP and PREEMPT kernel configuration variables, which can
happen once this implementation has accumulated sufficient experience.

Removed ACCESS_ONCE() from __rcu_read_unlock() and added barrier() as
suggested by Steve Rostedt in order to avoid the compiler-reordering
issue noted by Mathieu Desnoyers (http://lkml.org/lkml/2010/8/16/183).

As can be seen below, CONFIG_TINY_PREEMPT_RCU represents almost 5Kbyte
savings compared to CONFIG_TREE_PREEMPT_RCU.  Of course, for non-real-time
workloads, CONFIG_TINY_RCU is even better.

	CONFIG_TREE_PREEMPT_RCU

	   text	   data	    bss	    dec	   filename
	     13	      0	      0	     13	   kernel/rcupdate.o
	   6170	    825	     28	   7023	   kernel/rcutree.o
				   ----
				   7026    Total

	CONFIG_TINY_PREEMPT_RCU

	   text	   data	    bss	    dec	   filename
	     13	      0	      0	     13	   kernel/rcupdate.o
	   2081	     81	      8	   2170	   kernel/rcutiny.o
				   ----
				   2183    Total

	CONFIG_TINY_RCU (non-preemptible)

	   text	   data	    bss	    dec	   filename
	     13	      0	      0	     13	   kernel/rcupdate.o
	    719	     25	      0	    744	   kernel/rcutiny.o
				    ---
				    757    Total

Requested-by: Loïc Minier <loic.minier@canonical.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-08-20 08:55:00 -07:00
Mathieu Desnoyers
5e8067adfd rcu head remove init
RCU heads really don't need to be initialized. Their state before call_rcu()
really does not matter.

We need to keep init/destroy_rcu_head_on_stack() though, since we want
debugobjects to be able to keep track of these objects.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: David S. Miller <davem@davemloft.net>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: akpm@linux-foundation.org
CC: mingo@elte.hu
CC: laijs@cn.fujitsu.com
CC: dipankar@in.ibm.com
CC: josh@joshtriplett.org
CC: dvhltc@us.ibm.com
CC: niv@us.ibm.com
CC: tglx@linutronix.de
CC: peterz@infradead.org
CC: rostedt@goodmis.org
CC: Valdis.Kletnieks@vt.edu
CC: dhowells@redhat.com
CC: eric.dumazet@gmail.com
CC: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:03 -07:00
Arnd Bergmann
4d2deb40b2 kernel: __rcu annotations
This adds annotations for RCU operations in core kernel components

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:03 -07:00
Arnd Bergmann
d2c2486bc8 idr: __rcu annotations
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:03 -07:00
Arnd Bergmann
a1115570b3 radix-tree: __rcu annotations
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Nick Piggin <npiggin@suse.de>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:03 -07:00
Arnd Bergmann
374a8e0dc3 notifiers: __rcu annotations
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:02 -07:00
Paul E. McKenney
77d8485a8b rcu: improve kerneldoc for rcu_read_lock(), call_rcu(), and synchronize_rcu()
Make it explicit that new RCU read-side critical sections that start
after call_rcu() and synchronize_rcu() start might still be running
after the end of the relevant grace period.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:02 -07:00
Tetsuo Handa
4221a9918e Add RCU check for find_task_by_vpid().
find_task_by_vpid() says "Must be called under rcu_read_lock().". But due to
commit 3120438 "rcu: Disable lockdep checking in RCU list-traversal primitives",
we are currently unable to catch "find_task_by_vpid() with tasklist_lock held
but RCU lock not held" errors due to the RCU-lockdep checks being
suppressed in the RCU variants of the struct list_head traversals.
This commit therefore places an explicit check for being in an RCU
read-side critical section in find_task_by_pid_ns().

  ===================================================
  [ INFO: suspicious rcu_dereference_check() usage. ]
  ---------------------------------------------------
  kernel/pid.c:386 invoked rcu_dereference_check() without protection!

  other info that might help us debug this:

  rcu_scheduler_active = 1, debug_locks = 1
  1 lock held by rc.sysinit/1102:
   #0:  (tasklist_lock){.+.+..}, at: [<c1048340>] sys_setpgid+0x40/0x160

  stack backtrace:
  Pid: 1102, comm: rc.sysinit Not tainted 2.6.35-rc3-dirty #1
  Call Trace:
   [<c105e714>] lockdep_rcu_dereference+0x94/0xb0
   [<c104b4cd>] find_task_by_pid_ns+0x6d/0x70
   [<c104b4e8>] find_task_by_vpid+0x18/0x20
   [<c1048347>] sys_setpgid+0x47/0x160
   [<c1002b50>] sysenter_do_call+0x12/0x36

Commit updated to use a new rcu_lockdep_assert() exported API rather than
the old internal __do_rcu_dereference().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:02 -07:00
Arnd Bergmann
4b6a2872a2 kvm: add __rcu annotations
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:01 -07:00
Arnd Bergmann
2be8527928 input: __rcu annotations
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:01 -07:00
Arnd Bergmann
5b22216e11 nfs: __rcu annotations
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2010-08-19 17:18:00 -07:00
Arnd Bergmann
e63ba744a6 keys: __rcu annotations
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:00 -07:00
Arnd Bergmann
1b0ba1c903 credentials: rcu annotation
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:00 -07:00
Arnd Bergmann
2c392b8c34 cgroups: __rcu annotations
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:00 -07:00
Arnd Bergmann
67bdbffd69 rculist: avoid __rcu annotations
This avoids warnings from missing __rcu annotations
in the rculist implementation, making it possible to
use the same lists in both RCU and non-RCU cases.

We can add rculist annotations later, together with
lockdep support for rculist, which is missing as well,
but that may involve changing all the users.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:18:00 -07:00
Paul E. McKenney
ca5ecddfa8 rcu: define __rcu address space modifier for sparse
This commit provides definitions for the __rcu annotation defined earlier.
This annotation permits sparse to check for correct use of RCU-protected
pointers.  If a pointer that is annotated with __rcu is accessed
directly (as opposed to via rcu_dereference(), rcu_assign_pointer(),
or one of their variants), sparse can be made to complain.  To enable
such complaints, use the new default-disabled CONFIG_SPARSE_RCU_POINTER
kernel configuration option.  Please note that these sparse complaints are
intended to be a debugging aid, -not- a code-style-enforcement mechanism.

There are special rcu_dereference_protected() and rcu_access_pointer()
accessors for use when RCU read-side protection is not required, for
example, when no other CPU has access to the data structure in question
or while the current CPU hold the update-side lock.

This patch also updates a number of docbook comments that were showing
their age.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Christopher Li <sparse@chrisli.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2010-08-19 17:17:59 -07:00
Linus Torvalds
145c3ae46b Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  fs: brlock vfsmount_lock
  fs: scale files_lock
  lglock: introduce special lglock and brlock spin locks
  tty: fix fu_list abuse
  fs: cleanup files_lock locking
  fs: remove extra lookup in __lookup_hash
  fs: fs_struct rwlock to spinlock
  apparmor: use task path helpers
  fs: dentry allocation consolidation
  fs: fix do_lookup false negative
  mbcache: Limit the maximum number of cache entries
  hostfs ->follow_link() braino
  hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpy
  remove SWRITE* I/O types
  kill BH_Ordered flag
  vfs: update ctime when changing the file's permission by setfacl
  cramfs: only unlock new inodes
  fix reiserfs_evict_inode end_writeback second call
2010-08-18 09:35:08 -07:00
Linus Torvalds
86ea51d4a2 Merge branch 'merge-devicetree' of git://git.secretlab.ca/git/linux-2.6
* 'merge-devicetree' of git://git.secretlab.ca/git/linux-2.6:
  spi.h: missing kernel-doc notation, please fix
  of: fix missing headers for of_address_to_resource() in MTD and SysACE drivers
  of: Fix missing includes
  ata: update for of_device to platform_device replacement
  microblaze: Fix of: eliminate of_device->node and dev_archdata->{of,prom}_node
  microblaze: Fix of/address: Merge all of the bus translation code
  booting-without-of: Remove nonexistent chapters from TOC, fix numbering
2010-08-18 09:26:17 -07:00
Nick Piggin
6416ccb789 fs: scale files_lock
fs: scale files_lock

Improve scalability of files_lock by adding per-cpu, per-sb files lists,
protected with an lglock. The lglock provides fast access to the per-cpu lists
to add and remove files. It also provides a snapshot of all the per-cpu lists
(although this is very slow).

One difficulty with this approach is that a file can be removed from the list
by another CPU. We must track which per-cpu list the file is on with a new
variale in the file struct (packed into a hole on 64-bit archs). Scalability
could suffer if files are frequently removed from different cpu's list.

However loads with frequent removal of files imply short interval between
adding and removing the files, and the scheduler attempts to avoid moving
processes too far away. Also, even in the case of cross-CPU removal, the
hardware has much more opportunity to parallelise cacheline transfers with N
cachelines than with 1.

A worst-case test of 1 CPU allocating files subsequently being freed by N CPUs
degenerates to contending on a single lock, which is no worse than before. When
more than one CPU are allocating files, even if they are always freed by
different CPUs, there will be more parallelism than the single-lock case.

Testing results:

On a 2 socket, 8 core opteron, I measure the number of times the lock is taken
to remove the file, the number of times it is removed by the same CPU that
added it, and the number of times it is removed by the same node that added it.

Booting:    locks=  25049 cpu-hits=  23174 (92.5%) node-hits=  23945 (95.6%)
kbuild -j16 locks=2281913 cpu-hits=2208126 (96.8%) node-hits=2252674 (98.7%)
dbench 64   locks=4306582 cpu-hits=4287247 (99.6%) node-hits=4299527 (99.8%)

So a file is removed from the same CPU it was added by over 90% of the time.
It remains within the same node 95% of the time.

Tim Chen ran some numbers for a 64 thread Nehalem system performing a compile.

                throughput
2.6.34-rc2      24.5
+patch          24.9

                us      sys     idle    IO wait (in %)
2.6.34-rc2      51.25   28.25   17.25   3.25
+patch          53.75   18.5    19      8.75

So significantly less CPU time spent in kernel code, higher idle time and
slightly higher throughput.

Single threaded performance difference was within the noise of microbenchmarks.
That is not to say penalty does not exist, the code is larger and more memory
accesses required so it will be slightly slower.

Cc: linux-kernel@vger.kernel.org
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:48 -04:00
Nick Piggin
2dc91abe03 lglock: introduce special lglock and brlock spin locks
lglock: introduce special lglock and brlock spin locks

This patch introduces "local-global" locks (lglocks). These can be used to:

- Provide fast exclusive access to per-CPU data, with exclusive access to
  another CPU's data allowed but possibly subject to contention, and to provide
  very slow exclusive access to all per-CPU data.
- Or to provide very fast and scalable read serialisation, and to provide
  very slow exclusive serialisation of data (not necessarily per-CPU data).

Brlocks are also implemented as a short-hand notation for the latter use
case.

Thanks to Paul for local/global naming convention.

Cc: linux-kernel@vger.kernel.org
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:48 -04:00
Nick Piggin
d996b62a8d tty: fix fu_list abuse
tty: fix fu_list abuse

tty code abuses fu_list, which causes a bug in remount,ro handling.

If a tty device node is opened on a filesystem, then the last link to the inode
removed, the filesystem will be allowed to be remounted readonly. This is
because fs_may_remount_ro does not find the 0 link tty inode on the file sb
list (because the tty code incorrectly removed it to use for its own purpose).
This can result in a filesystem with errors after it is marked "clean".

Taking idea from Christoph's initial patch, allocate a tty private struct
at file->private_data and put our required list fields in there, linking
file and tty. This makes tty nodes behave the same way as other device nodes
and avoid meddling with the vfs, and avoids this bug.

The error handling is not trivial in the tty code, so for this bugfix, I take
the simple approach of using __GFP_NOFAIL and don't worry about memory errors.
This is not a problem because our allocator doesn't fail small allocs as a rule
anyway. So proper error handling is left as an exercise for tty hackers.

[ Arguably filesystem's device inode would ideally be divorced from the
driver's pseudo inode when it is opened, but in practice it's not clear whether
that will ever be worth implementing. ]

Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:47 -04:00
Nick Piggin
ee2ffa0dfd fs: cleanup files_lock locking
fs: cleanup files_lock locking

Lock tty_files with a new spinlock, tty_files_lock; provide helpers to
manipulate the per-sb files list; unexport the files_lock spinlock.

Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:47 -04:00
Nick Piggin
2a4419b5b2 fs: fs_struct rwlock to spinlock
fs: fs_struct rwlock to spinlock

struct fs_struct.lock is an rwlock with the read-side used to protect root and
pwd members while taking references to them. Taking a reference to a path
typically requires just 2 atomic ops, so the critical section is very small.
Parallel read-side operations would have cacheline contention on the lock, the
dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a
real parallelism increase.

Replace it with a spinlock to avoid one or two atomic operations in typical
path lookup fastpath.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:46 -04:00
Christoph Hellwig
9cb569d601 remove SWRITE* I/O types
These flags aren't real I/O types, but tell ll_rw_block to always
lock the buffer instead of giving up on a failed trylock.

Instead add a new write_dirty_buffer helper that implements this semantic
and use it from the existing SWRITE* callers.  Note that the ll_rw_block
code had a bug where it didn't promote WRITE_SYNC_PLUG properly, which
this patch fixes.

In the ufs code clean up the helper that used to call ll_rw_block
to mirror sync_dirty_buffer, which is the function it implements for
compound buffers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 01:09:01 -04:00
Christoph Hellwig
87e99511ea kill BH_Ordered flag
Instead of abusing a buffer_head flag just add a variant of
sync_dirty_buffer which allows passing the exact type of write
flag required.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 01:09:00 -04:00
Ernst Schwab
5c79a5ae23 spi.h: missing kernel-doc notation, please fix
Added comments in kernel-doc notation for previously added struct fields.

Signed-off-by: Ernst Schwab <eschwab@online.de>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-08-17 22:55:38 -06:00
Linus Torvalds
2a6a432a9c Merge master.kernel.org:/home/rmk/linux-2.6-arm
* master.kernel.org:/home/rmk/linux-2.6-arm:
  VIDEO: amba clcd: don't disable an already disabled clock
  ARM: Tighten check for allowable CPSR values
  ARM: 6329/1: wire up sys_accept4() on ARM
  ARM: 6328/1: Build with -fno-dwarf2-cfi-asm
  ARM: 6326/1: kgdb: fix GDB_MAX_REGS no longer used
2010-08-17 18:11:49 -07:00
David Howells
d7627467b7 Make do_execve() take a const filename pointer
Make do_execve() take a const filename pointer so that kernel_execve() compiles
correctly on ARM:

arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type

This also requires the argv and envp arguments to be consted twice, once for
the pointer array and once for the strings the array points to.  This is
because do_execve() passes a pointer to the filename (now const) to
copy_strings_kernel().  A simpler alternative would be to cast the filename
pointer in do_execve() when it's passed to copy_strings_kernel().

do_execve() may not change any of the strings it is passed as part of the argv
or envp lists as they are some of them in .rodata, so marking these strings as
const should be fine.

Further kernel_execve() and sys_execve() need to be changed to match.

This has been test built on x86_64, frv, arm and mips.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-17 18:07:43 -07:00
Russell King
99c796df94 VIDEO: amba clcd: don't disable an already disabled clock
Fix the clock enable/disable tracking in the AMBA CLCD driver so
that the driver doesn't try to disable an already disabled clock,
thereby causing the clock (if shared) to become unbalanced.

This resolves a problem with CLCD on LPC32xx ARM platforms.

Reported-by: Kevin Wells <wellsk40@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-08-17 22:15:09 +01:00
Linus Torvalds
2245ba2a3a Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
  gcc-4.6: ACPI: fix unused but set variables in ACPI
  ACPI thermal: make procfs I/F depend on CONFIG_ACPI_PROCFS
  ACPI video: make procfs I/F depend on CONFIG_ACPI_PROCFS
  ACPI processor: remove deprecated ACPI procfs I/F
  ACPI power_resource: remove unused procfs I/F
  ACPI: remove deprecated ACPI procfs I/F
  ACPI: introduce drivers/acpi/sysfs.c
  ACPI: introduce module parameter acpi.aml_debug_output
  ACPI: introduce drivers/acpi/debugfs.c
  ACPI, APEI, ERST debug support
  ACPI, APEI, Manage GHES as platform devices
  ACPI, APEI, Rename CPER and GHES severity constants
  ACPI, APEI, Fix a typo of error path of apei_resources_request
  ACPI / ACPICA: Fix reference counting problems with GPE handlers
  ACPI: Add the check of ADR flag in course of finding ACPI handle for PCI device
  ACPI / Sleep: Drop acpi_suspend_finish()
  ACPI / Sleep: Consolidate suspend and hibernation routines
  ACPI / Wakeup: Simplify enabling of wakeup devices
  ACPI / Sleep: Rework enabling wakeup devices
  ACPI / Sleep: Free NVS copy if suspending of devices fails

Fixed up totally buggered "ACPI: fix unused but set variables in ACPI"
patch that doesn't even compile in the merge.

Thanks to Sedat Dilek <sedat.dilek@googlemail.com> for noticing the
breakage before I even pulled.  And a big "Grrr.." at Len for not even
bothering to compile the tree before asking me to pull.
2010-08-15 17:37:07 -07:00
Len Brown
95ee46aa86 Merge branch 'linus' into release
Conflicts:
	drivers/acpi/debug.c

Signed-off-by: Len Brown <len.brown@intel.com>
2010-08-15 01:06:31 -04:00
Linus Torvalds
5d7cb15702 Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/cleanup
* git://git.kernel.org/pub/scm/linux/kernel/git/sam/cleanup:
  defconfig reduction
  kbuild: drop unifdef-y support
  archs: replace unifdef-y with header-y
  include: replace unifdef-y with header-y
2010-08-14 16:21:50 -07:00
Linus Torvalds
d310ad0c9d Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging: (22 commits)
  hwmon: (via-cputemp) Remove bogus "SHOW" global variable
  hwmon: jc42 depends on I2C
  hwmon: (pc87427) Add a maintainer
  hwmon: (pc87427) Move sysfs file removal to a separate function
  hwmon: (pc87427) Add temperature monitoring support
  hwmon: (pc87427) Add support for the second logical device
  hwmon: (pc87427) Add support for manual fan speed control
  hwmon: (pc87427) Minor style cleanups
  hwmon: (pc87427) Handle disabled fan inputs properly
  hwmon: (w83627ehf) Add support for W83667HG-B
  hwmon: (w83627ehf) Driver cleanup
  hwmon: Add driver for SMSC EMC2103 temperature monitor and fan controller
  hwmon: Remove in[0-*]_fault from sysfs-interface
  hwmon: Add 4 current alarm/beep attributes to sysfs-interface
  hwmon: Add 3 critical limit attributes to sysfs-interface
  hwmon: (asc7621) Clean up and improve detect function
  hwmon: (it87) Export labels for internal sensors
  hwmon: (lm75) Add suspend/resume feature
  hwmon: (emc1403) Add power support
  hwmon: (ltc4245) Expose all GPIO pins as analog voltages
  ...
2010-08-14 14:57:58 -07:00
Sam Ravnborg
60641aa1f3 include: replace unifdef-y with header-y
unifdef-y and header-y has same semantic.
So there is no need to have both.

Drop the unifdef-y variant and sort all lines again

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2010-08-14 22:26:51 +02:00
Ira W. Snyder
5950ec8d3e hwmon: (ltc4245) Expose all GPIO pins as analog voltages
Add support for exposing all GPIO pins as analog voltages. Though this is
not an ideal use of the chip, some hardware engineers may decide that the
LTC4245 meets their design requirements when studying the datasheet.

The GPIO pins are sampled in round-robin fashion, meaning that a slow
reader will see stale data. A userspace application can detect this,
because it will get -EAGAIN when reading from a sysfs file which contains
stale data.

Users can choose to use this feature on a per-chip basis by using either
platform data or the OF device tree (where applicable).

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-08-14 21:08:49 +02:00
Linus Torvalds
b171aa2770 Merge branch 'next-spi' of git://git.secretlab.ca/git/linux-2.6
* 'next-spi' of git://git.secretlab.ca/git/linux-2.6:
  spi/amba_pl022: Fix probe and remove hook section annotations.
  spi/mpc5121: change annotations for probe and remove functions
  spi/bitbang: reinitialize transfer parameters for every message
  spi/spi-gpio: add support for controllers without MISO or MOSI pin
  spi/bitbang: add support for SPI_MASTER_NO_{TX, RX} modes
  SPI100k: Fix 8-bit and RX-only transfers
  spi/mmc_spi: mmc_spi adaptations for SPI bus locking API
  spi/mmc_spi: SPI bus locking API, using mutex

Fix trivial conflict in drivers/spi/mpc512x_psc_spi.c due to 'struct
of_device' => 'struct platform_device' rename and __init/__exit to
__devinit/__devexit fix.
2010-08-14 11:54:09 -07:00
Linus Torvalds
10041d2d14 Merge branch 'bkl/ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing
* 'bkl/ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing:
  bkl: Remove locked .ioctl file operation
  v4l: Remove reference to bkl ioctl in compat ioctl handling
  logfs: kill BKL
2010-08-13 17:52:35 -07:00
David Howells
c788732523 Mark arguments to certain syscalls as being const
Mark arguments to certain system calls as being const where they should be but
aren't.  The list includes:

 (*) The filename arguments of various stat syscalls, execve(), various utimes
     syscalls and some mount syscalls.

 (*) The filename arguments of some syscall helpers relating to the above.

 (*) The buffer argument of various write syscalls.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-13 16:53:13 -07:00
Arnd Bergmann
b19dd42faf bkl: Remove locked .ioctl file operation
The last user is gone, so we can safely remove this

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: John Kacur <jkacur@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-08-14 00:24:24 +02:00
Heiko Carstens
e259f191f2 dma-mapping: fix build errors on !HAS_DMA architectures
commit 4565f0170d "dma-mapping: unify
dma_get_cache_alignment implementations" causes build errors on
!HAS_DMA architectures/platforms like s390 and sun3:

include/linux/dma-mapping.h:145: error: static declaration of 'dma_get_cache_alignment' follows non-static declaration
include/asm-generic/dma-mapping-broken.h:73: error: previous declaration of 'dma_get_cache_alignment' was here

Fix this by adding an explicit ifdef.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-13 12:03:24 -07:00
Linus Torvalds
2f2c779583 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (30 commits)
  ctcm: rename READ/WRITE defines to avoid redefinitions
  claw: rename READ/WRITE defines to avoid redefinitions
  phylib: available for any speed ethernet
  can: add limit for nframes and clean up signed/unsigned variables
  pkt_sched: Check .walk and .leaf class handlers
  pkt_sched: Fix sch_sfq vs tc_modify_qdisc oops
  caif-spi: Bugfix SPI_DATA_POS settings were inverted.
  caif: Bugfix - Increase default headroom size for control channel.
  net: make netpoll_rx return bool for !CONFIG_NETPOLL
  Bluetooth: Use 3-DH5 payload size for default ERTM max PDU size
  Bluetooth: Fix incorrect setting of remote_tx_win for L2CAP ERTM
  Bluetooth: Change default L2CAP ERTM retransmit timeout
  Bluetooth: Fix endianness issue with L2CAP MPS configuration
  net: Use NET_XMIT_SUCCESS where possible.
  isdn: mISDN: call pci_disable_device() if pci_probe() failed
  isdn: avm: call pci_disable_device() if pci_probe() failed
  isdn: avm: call pci_disable_device() if pci_probe() failed
  usbnet: rx_submit() should return an error code.
  pkt_sched: Add some basic qdisc class ops verification. Was: [PATCH] sfq: add dummy bind/unbind handles
  pkt_sched: sch_sfq: Add dummy unbind_tcf and put handles. Was: [PATCH] sfq: add dummy bind/unbind handles
  ...
2010-08-13 10:38:12 -07:00
Linus Torvalds
2069601b3f Revert "fsnotify: store struct file not struct path"
This reverts commit 3bcf3860a4 (and the
accompanying commit c1e5c95402 "vfs/fsnotify: fsnotify_close can delay
the final work in fput" that was a horribly ugly hack to make it work at
all).

The 'struct file' approach not only causes that disgusting hack, it
somehow breaks pulseaudio, probably due to some other subtlety with
f_count handling.

Fix up various conflicts due to later fsnotify work.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 14:23:04 -07:00
Linus Torvalds
8357422d4b Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm
* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: (33 commits)
  dm mpath: support discard
  dm stripe: support discards
  dm: split discard requests on target boundaries
  dm stripe: optimize sector division
  dm stripe: move sector translation to a function
  dm: error return error for discards
  dm delay: support discard
  dm: zero silently drop discards
  dm: use dm_target_offset macro
  dm: factor out max_io_len_target_boundary
  dm: use common __issue_target_request for flush and discard support
  dm: linear support discard
  dm crypt: simplify crypt_ctr
  dm crypt: simplify crypt_config destruction logic
  dm: allow autoloading of dm mod
  dm: rename map_info flush_request to target_request_nr
  dm ioctl: refactor dm_table_complete
  dm snapshot: implement merge
  dm: do not initialise full request queue when bio based
  dm ioctl: make bio or request based device type immutable
  ...
2010-08-12 10:16:46 -07:00
Linus Torvalds
1021a64534 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6:
  hugetlb: add missing unlock in avoidcopy path in hugetlb_cow()
  hwpoison: rename CONFIG
  HWPOISON, hugetlb: support hwpoison injection for hugepage
  HWPOISON, hugetlb: detect hwpoison in hugetlb code
  HWPOISON, hugetlb: isolate corrupted hugepage
  HWPOISON, hugetlb: maintain mce_bad_pages in handling hugepage error
  HWPOISON, hugetlb: set/clear PG_hwpoison bits on hugepage
  HWPOISON, hugetlb: enable error handling path for hugepage
  hugetlb, rmap: add reverse mapping for hugepage
  hugetlb: move definition of is_vm_hugetlb_page() to hugepage_inline.h

Fix up trivial conflicts in mm/memory-failure.c
2010-08-12 10:15:10 -07:00
Linus Torvalds
7367f5b013 Merge branch 'for-linus' of git://neil.brown.name/md
* 'for-linus' of git://neil.brown.name/md:
  Further tidyup of raid6 naming in lib/raid6
  Make lib/raid6/test build correctly.
  Rename raid6 files now they're in a 'raid6' directory.
2010-08-12 10:08:10 -07:00
Linus Torvalds
1c00650c23 Merge branch 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging
* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  i2c: I2C bus multiplexer driver pca954x
  i2c: Multiplexed I2C bus core support
  i2c: Use a separate mutex for userspace client lists
  i2c: Make i2c_default_probe self-sufficient
  i2c: Drop dummy variable
  i2c: Move adapter locking helpers to i2c-core
  V4L/DVB: Use custom I2C probing function mechanism
  i2c: Add support for custom probe function
  i2c-dev: Use memdup_user
  i2c-dev: Remove unnecessary kmalloc casts
2010-08-12 10:06:29 -07:00
Linus Torvalds
26df0766a7 Merge branch 'params' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
* 'params' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (22 commits)
  param: don't deref arg in __same_type() checks
  param: update drivers/acpi/debug.c to new scheme
  param: use module_param in drivers/message/fusion/mptbase.c
  ide: use module_param_named rather than module_param_call
  param: update drivers/char/ipmi/ipmi_watchdog.c to new scheme
  param: lock if_sdio's lbs_helper_name and lbs_fw_name against sysfs changes.
  param: lock myri10ge_fw_name against sysfs changes.
  param: simple locking for sysfs-writable charp parameters
  param: remove unnecessary writable charp
  param: add kerneldoc to moduleparam.h
  param: locking for kernel parameters
  param: make param sections const.
  param: use free hook for charp (fix leak of charp parameters)
  param: add a free hook to kernel_param_ops.
  param: silence .init.text references from param ops
  Add param ops struct for hvc_iucv driver.
  nfs: update for module_param_named API change
  AppArmor: update for module_param_named API change
  param: use ops in struct kernel_param, rather than get and set fns directly
  param: move the EXPORT_SYMBOL to after the definitions.
  ...
2010-08-12 10:01:59 -07:00