groups_sort() can be quite long if user loads a large gid table.

This is because GROUP_AT(group_info, some_integer) uses an integer divide.
So having to do XXX thousand divides during one syscall can lead to very
high latencies.  (NGROUPS_MAX=65536)

In the past (25 Mar 2006), an analog problem was found in groups_search()
(commit d74beb9f ) and at that time I
changed some variables to unsigned int.

I believe that a more generic fix is to make sure NGROUPS_PER_BLOCK is
unsigned.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the following section mismatch with CONFIG_HOTPLUG=n,
CONFIG_HOTPLUG_CPU=y:

WARNING: vmlinux.o(.text+0x399a6): Section mismatch: reference to .init.text.5:idle_regs (between 'fork_idle' and 'get_task_mm')
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

calibrate_delay() must be __cpuinit, not __{dev,}init.

I've verified that this is correct for all users.

While doing the latter, I also did the following cleanups:
- remove pointless additional prototypes in C files
- ensure all users #include <linux/delay.h>

This fixes the following section mismatches with CONFIG_HOTPLUG=n,
CONFIG_HOTPLUG_CPU=y:

WARNING: vmlinux.o(.text+0x1128d): Section mismatch: reference to .init.text.1:calibrate_delay (between 'check_cx686_slop' and 'set_cx86_reorder')
WARNING: vmlinux.o(.text+0x25102): Section mismatch: reference to .init.text.1:calibrate_delay (between 'smp_callin' and 'cpu_coregroup_map')
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Christian Zankel <chris@zankel.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fixing:
  CHECK   kernel/params.c
kernel/params.c:329:41: warning: incorrect type in argument 8 (different signedness)
kernel/params.c:329:41:    expected int *num
kernel/params.c:329:41:    got unsigned int *
Signed-off-by: NRichard Knutsson <ricknu-0@student.ltu.se>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Actual code let compiler generates idiv instruction on x86.

Using a right shift is OK here and readable as well.

Before patch
   10:   57                      push   %edi
   11:   56                      push   %esi
   12:   89 d6                   mov    %edx,%esi
   14:   53                      push   %ebx
   15:   89 c3                   mov    %eax,%ebx
   17:   eb 22                   jmp    3b <search_extable+0x2b>
   19:   89 f0                   mov    %esi,%eax
   1b:   ba 02 00 00 00          mov    $0x2,%edx
   20:   29 d8                   sub    %ebx,%eax
   22:   89 d7                   mov    %edx,%edi
   24:   c1 f8 03                sar    $0x3,%eax
   27:   99                      cltd
   28:   f7 ff                   idiv   %edi
   2a:   8d 04 c3                lea    (%ebx,%eax,8),%eax
   2d:   39 08                   cmp    %ecx,(%eax)
...

After patch

00000010 <search_extable>:
   10:   53                      push   %ebx
   11:   89 c3                   mov    %eax,%ebx
   13:   eb 18                   jmp    2d <search_extable+0x1d>
   15:   89 d0                   mov    %edx,%eax
   17:   29 d8                   sub    %ebx,%eax
   19:   c1 f8 04                sar    $0x4,%eax
   1c:   8d 04 c3                lea    (%ebx,%eax,8),%eax
   1f:   39 08                   cmp    %ecx,(%eax)
...
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add detection for IT87XX SuperIO chip and disabling its POST feature, which
made noise on parallel port's pins.
Signed-off-by: NPetr Cvek <petr.cvek@tul.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add the Dell UK 6400 Inspiron model (MM061) to allow the i8k module to load
correctly without using 'force=1'
Signed-off-by: N"Nick Warne" <nick@ukfsn.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use DEFAULT_SGI_PARTITION for SGI_PARTION default
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix wrong netmos 9855 serial port configuration.

On loading only one serial port was present and it wasn't working.  After
looking in the data sheet I realized that the base address was wrong.  For
further reference here is lspci and relevant dmesg output:

02:00.0 Communication controller: NetMos Technology PCI 9855 Multi-I/O
Controller (rev 01) (prog-if 02)
        Subsystem: LSI Logic / Symbios Logic Unknown device 0022
        Flags: medium devsel, IRQ 19
        I/O ports at df00 [size=8]
        I/O ports at de00 [size=8]
        I/O ports at dd00 [size=8]
        I/O ports at dc00 [size=8]
        I/O ports at db00 [size=8]
        I/O ports at da00 [size=16]

parport1: PC-style at 0xdd00 [PCSPP,TRISTATE]
parport2: PC-style at 0xdf00 [PCSPP,TRISTATE,EPP]
0000:02:00.0: ttyS0 at I/O 0xdb00 (irq = 19) is a 16550A
0000:02:00.0: ttyS1 at I/O 0xda00 (irq = 19) is a 16550A
Signed-off-by: NChristian Pellegrin <chripell@fsfe.org>
Cc: Thomas Richter <thor@math.TU-Berlin.DE>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Martin Schitter <ms@gewi.kfunigraz.ac.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Added pci device id for the Quatech SPPXP-100 ExpressCard - 0x278 - to
include/linux/pci_id.h

Modified drivers/parport/parport_pc.c to support the Quatech SPPXP-100 Parallel port PCI ExpressCard

[akpm@linux-foundation.org: build fix]
Signed-off-by: NLuís P Mendes <luis.p.mendes@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ext2 should not worry about checking sb->s_blocksize for XIP before the
sb's blocksize actually gets set.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The port_write_mutex was converted from a semaphore to a mutex,
but there was still this ifdef'd init_MUTEX reference remaining.
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

[akpm@linux-foundation.org: cleanup]
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDenis Cheng <crquan@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDenis Cheng <crquan@gmail.com>
Cc: Corey Minyard <minyard@acm.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I converted some of the document to reflect mutex usage instead of
semaphore usage.  Since we shouldin't be promoting semaphore usage when
it's on it's way out..
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Turn on INTR/QUIT/SUSP echoing in the N_TTY line discipline (e.g.  ctrl-C
will appear as "^C" if stty echoctl is set and ctrl-C is set as INTR).

Linux seems to be the only unix-like OS (recently I've verified this on
Solaris, BSD, and Mac OS X) that does *not* behave this way, and I really
miss this as a good visual confirmation of the interrupt of a program in
the console or xterm.  I remember this fondly from many Unixs I've used
over the years as well.  Bringing this to Linux also seems like a good way
to make it yet more compliant with standard unix-like behavior.

[akpm@linux-foundation.org: coding-style fixes]
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds support to allow asm/ptrace.h to define two new macros,
arch_ptrace_stop_needed and arch_ptrace_stop.  These control special
machine-specific actions to be done before a ptrace stop.  The new code
compiles away to nothing when the new macros are not defined.  This is the
case on all machines to begin with.

On ia64, these macros will be defined to solve the long-standing issue of
ptrace vs register backing store.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Cc: Petr Tesarik <ptesarik@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Matthew Wilcox <willy@debian.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We restarted scan of sb->s_inodes list whenever we had to drop inode_lock
in add_dquot_ref().  This leads to overall quadratic running time and thus
add_dquot_ref() can take several minutes when called on a life filesystem.
We fix the problem by using the fact that inode cannot be removed from
s_inodes list while we hold a reference to it and thus we can safely
restart the scan if we don't drop the reference.  Here we use the fact that
inodes freshly added to s_inodes list are already guaranteed to have quotas
properly initialized and the ordering of inodes on s_inodes list does not
change so we cannot skip any inode.

Thanks goes to Nick <gentuu@gmail.com> for analyzing the problem and
testing the fix.

[akpm@linux-foundation.org: iput(NULL) is legal]
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: Nick <gentuu@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

single list_head variable initialized with LIST_HEAD_INIT could almost
always can be replaced with LIST_HEAD declaration, this shrinks the code
and looks better.
Signed-off-by: NDenis Cheng <crquan@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Corey Minyard <minyard@acm.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert uio from nopage to fault.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NHans J Koch <hjk@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert relay from nopage to fault.
Remove redundant vma range checks.
Switch from OOM to SIGBUS if the resource is not available.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Tom Zanussi <zanussi@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When resolving symbol names from addresses with aliased symbol names,
kallsyms_lookup always returns the first symbol, even if it is a weak
symbol.

This patch changes this by sorting the symbols with the weak symbols last
before feeding them to the kernel.  This way the kernel runtime isn't
changed at all, only the kallsyms build system is changed.

Another side effect is that the symbols get sorted by address, too.  So,
even if future binutils version have some bug in "nm" that makes it fail to
correctly sort symbols by address, the kernel won't be affected by this.

Mathieu says:

  I created a module in LTTng that uses kallsyms to get the symbol
  corresponding to a specific system call address.  Unfortunately, all the
  unimplemented syscalls were all referring to the (same) weak symbol
  identifying an unrelated system call rather that sys_ni (or whatever
  non-weak symbol would be expected).  Kallsyms was dumbly returning the first
  symbol that matched.

  This patch makes sure kallsyms returns the non-weak symbol when there is
  one, which seems to be the expected result.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Looks-great-to: Rusty Russell <rusty@rustcorp.com.au>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert the unix98 allocated_ptys_lock to a mutex.
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I couldn't find any users, so removing it..
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I couldn't find any users, so removing it..
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Acked-by: NAlan Cox <alan@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Here's a document I wrote after figuring out what unaligned memory access
is all about.  I've tried to cover the information I was looking for when
trying to learn about this, without producing a hopelessly detailed/complex
spew.  I hope it is useful to others.
Signed-off-by: NDaniel Drake <dsd@gentoo.org>
Cc: Rob Landley <rob@landley.net>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Jan Engelhardt <jengelh@computergmbh.de>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Kyle Moffett <mrmacman_g4@mac.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The inotify debugging code is supposed to verify that the
DCACHE_INOTIFY_PARENT_WATCHED scalability optimisation does not result in
notifications getting lost nor extra needless locking generated.

Unfortunately there are also some races in the debugging code.  And it isn't
very good at finding problems anyway.  So remove it for now.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Robert Love <rlove@google.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Jan Kara <jack@ucw.cz>
Cc: Yan Zheng <yanzheng@21cn.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a race between setting an inode's children's "parent watched" flag
when placing the first watch on a parent, and instantiating new children of
that parent: a child could miss having its flags set by
set_dentry_child_flags, but then inotify_d_instantiate might still see
!inotify_inode_watched.

The solution is to set_dentry_child_flags after adding the watch.  Locking is
taken care of, because both set_dentry_child_flags and inotify_d_instantiate
hold dcache_lock and child->d_locks.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Robert Love <rlove@google.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Jan Kara <jack@ucw.cz>
Cc: Yan Zheng <yanzheng@21cn.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

New serial driver for SC2681/SC2691 uarts.  Older SNI RM400 machines are
using these chips for onboard serial ports.
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Torben Mathiasen <device@lanana.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use SGI_HAS_DS1286 for SGI_DS1286 depends
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- Use SGI_HAS_ZILOG for IP22_ZILOG depends
- remove IP22 from description, because the driver works on more than
  IP22 SGI machines
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Given that init/Makefile includes initramfs.c in the build only if
CONFIG_BLK_DEV_INITRD is defined, there seems to be no point checking for
it yet again.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The rcu_assign_pointer() primitive currently unconditionally executes a
memory barrier, even when a NULL pointer is being assigned.  This has lead
some to avoid using rcu_assign_pointer() for NULL pointers, which loses the
self-documenting advantages of rcu_assign_pointer() This patch uses
__builtin_const_p() to omit needless memory barriers for NULL-pointer
assignments at compile time with no runtime penalty, as discussed in the
following thread:

	http://www.mail-archive.com/netdev@vger.kernel.org/msg54852.html

Tested on x86_64 and ppc64, also compiled the four cases (NULL/non-NULL
and const/non-const) with gcc version 4.1.2, and hand-checked the
assembly output.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NQi Yong <qiyong@fc-cn.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Reduce latency for large writes to /dev/[u]random
Signed-off-by: NMatt Mackall <mpm@selenic.com>
Cc: Sami Farin <safari-kernel@safari.iki.fi>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The declaration and implementation of __const_udelay use different
names for the parameter on a number of architectures:

include/asm-avr32/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/avr32/lib/delay.c:39:inline void __const_udelay(unsigned long xloops)

include/asm-sh/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/sh/lib/delay.c:22:inline void __const_udelay(unsigned long xloops)

include/asm-m32r/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/m32r/lib/delay.c:58:void __const_udelay(unsigned long xloops)

include/asm-x86/delay.h:16:extern void __const_udelay(unsigned long usecs);
arch/x86/lib/delay_32.c:82:inline void __const_udelay(unsigned long xloops)
arch/x86/lib/delay_64.c:46:inline void __const_udelay(unsigned long xloops)

The units of the parameter isn't usecs, so that name is definitely
wrong.  It's also not exactly loops, so I suppose xloops is an OK
name.

This patch changes these names from usecs to xloops.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix missed serial input signal changes caused by rereading the serial
status register during interrupt processing.  Now processing is performed
on original status register value.
Signed-off-by: NPaul Fulghum <paulkf@microgate.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the recommended form of "<>" to include linux header files, and
move those includes up to join the rest of the linux includes.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Acked-by: NPaul Fulghum <paulkf@microgate.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

NR_OPEN (historically set to 1024*1024) actually forbids processes to open
more than 1024*1024 handles.

Unfortunatly some production servers hit the not so 'ridiculously high
value' of 1024*1024 file descriptors per process.

Changing NR_OPEN is not considered safe because of vmalloc space potential
exhaust.

This patch introduces a new sysctl (/proc/sys/fs/nr_open) wich defaults to
1024*1024, so that admins can decide to change this limit if their workload
needs it.

[akpm@linux-foundation.org: export it for sparc64]
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>