mm: replace remap_file_pages() syscall with emulation

remap_file_pages(2) was invented to be able efficiently map parts of huge
file into limited 32-bit virtual address space such as in database
workloads.

Nonlinear mappings are pain to support and it seems there's no legitimate
use-cases nowadays since 64-bit systems are widely available.

Let's drop it and get rid of all these special-cased code.

The patch replaces the syscall with emulation which creates new VMA on
each remap_file_pages(), unless they it can be merged with an adjacent
one.

I didn't find *any* real code that uses remap_file_pages(2) to test
emulation impact on.  I've checked Debian code search and source of all
packages in ALT Linux.  No real users: libc wrappers, mentions in strace,
gdb, valgrind and this kind of stuff.

There are few basic tests in LTP for the syscall. They work just fine
with emulation.

To test performance impact, I've written small test case which demonstrate
pretty much worst case scenario: map 4G shmfs file, write to begin of
every page pgoff of the page, remap pages in reverse order, read every
page.

The test creates 1 million of VMAs if emulation is in use, so I had to set
vm.max_map_count to 1100000 to avoid -ENOMEM.

Before: 23.3 ( +-  4.31% ) seconds
After: 43.9 ( +-  0.85% ) seconds
Slowdown: 1.88x

I believe we can live with that.

Test case:

#define _GNU_SOURCE
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>

#define MB (1024UL * 1024)
#define SIZE (4096 * MB)

int main(int argc, char **argv)
{
unsigned long *p;
long i, pass;

for (pass = 0; pass < 10; pass++) {
p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if (p == MAP_FAILED) {
perror("mmap");
return -1;
}

for (i = 0; i < SIZE / 4096; i++)
p[i * 4096 / sizeof(*p)] = i;

for (i = 0; i < SIZE / 4096; i++) {
if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096,
0, (SIZE - 4096 * (i + 1)) >> 12, 0)) {
perror("remap_file_pages");
return -1;
}
}

for (i = SIZE / 4096 - 1; i >= 0; i--)
assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1);

munmap(p, SIZE);
}

return 0;
}

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Armin Rigo <arigo@tunes.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/kprobes.c: convert printk to pr_foo()

Also fixes some checkpatch warnings
-Static initialization
-Lines over 80 characters

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/net/ethernet/amd/pcnet32.c: neaten and remove unnecessary OOM messages

Make the code flow a little better for 80 columns.

Use a consistent style for the RX and TX rings allocation.
Use BIT macro.
Use a temporary unsiged int entries for (1<<size).
Remove the OOM messages as they duplicate the generic
OOM and dump_stack() provided by the memory subsystem.
Reflow allocs to 80 columns.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Don Fry <pcnet32@frontier.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

vme: bridges: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Martyn Welch <martyn.welch@ge.com>
Cc: Manohar Vanga <manohar.vanga@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

synclink_gt: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

staging: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Lior Dotan <liodot@gmail.com>
Cc: Christopher Harrer <charrer@alacritech.com>
Cc: Forest Bond <forest@alittletooquiet.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

scsi: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Adam Radford <linuxraid@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Cc: Dario Ballabio <ballabio_dario@emc.com>
Cc: Michael Neuffer <mike@i-Connect.Net>
Cc: "Stephen M. Cameron" <scameron@beardog.cce.hp.com>
Cc: Neela Syam Kolli <megaraidlinux@lsi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

rtlwifi: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Chaoming Li <chaoming_li@realsil.com.cn>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

rtl818x: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mwl8k: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Lennert Buytenhek <buytenh@wantstofly.org>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

ipw2100: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Stanislav Yakovlev <stas.yakovlev@gmail.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

irda: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Samuel Ortiz <samuel@sortiz.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

qlogic: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Manish Chopra <manish.chopra@qlogic.com>
Cc: Sony Chacko <sony.chacko@qlogic.com>
Cc: Rajesh Borundia <rajesh.borundia@qlogic.com>
Cc: Shahed Shaikh <shahed.shaikh@qlogic.com>
Cc: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Cc: Ron Mercer <ron.mercer@qlogic.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

micrel: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

sky2: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Mirko Lindner <mlindner@marvell.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

enic: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Christian Benvenuti <benve@cisco.com>
Cc: Sujith Sankar <ssujith@cisco.com>
Cc: Govindarajulu Varadarajan <_govind@gmx.com>
Cc: Neel Patel <neepatel@cisco.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

atl1e: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

amd: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Don Fry <pcnet32@frontier.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

media: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

i810: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

infiniband: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

crypto: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

block: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Mike Miller <mike.miller@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

atm: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Chas Williams <chas@cmf.nrl.navy.mil>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

pci-dma-compat: add pci_zalloc_consistent helper

Add this helper for consistency with pci_zalloc_coherent
and the ability to remove unnecessary memset(,0,) uses.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: "Stephen M. Cameron" <scameron@beardog.cce.hp.com>
Cc: Adam Radford <linuxraid@lsi.com>
Cc: Chaoming Li <chaoming_li@realsil.com.cn>
Cc: Chas Williams <chas@cmf.nrl.navy.mil>
Cc: Christian Benvenuti <benve@cisco.com>
Cc: Christopher Harrer <charrer@alacritech.com>
Cc: Dario Ballabio <ballabio_dario@emc.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Don Fry <pcnet32@frontier.com>
Cc: Faisal Latif <faisal.latif@intel.com>
Cc: Forest Bond <forest@alittletooquiet.net>
Cc: Govindarajulu Varadarajan <_govind@gmx.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Lennert Buytenhek <buytenh@wantstofly.org>
Cc: Lior Dotan <liodot@gmail.com>
Cc: Manish Chopra <manish.chopra@qlogic.com>
Cc: Manohar Vanga <manohar.vanga@gmail.com>
Cc: Martyn Welch <martyn.welch@ge.com>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Michael Neuffer <mike@i-Connect.Net>
Cc: Mirko Lindner <mlindner@marvell.com>
Cc: Neel Patel <neepatel@cisco.com>
Cc: Neela Syam Kolli <megaraidlinux@lsi.com>
Cc: Rajesh Borundia <rajesh.borundia@qlogic.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Ron Mercer <ron.mercer@qlogic.com>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Shahed Shaikh <shahed.shaikh@qlogic.com>
Cc: Sony Chacko <sony.chacko@qlogic.com>
Cc: Stanislav Yakovlev <stas.yakovlev@gmail.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Sujith Sankar <ssujith@cisco.com>
Cc: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux: remove strict_strto* definitions

Remove obsolete and unused strict_strto* functions

Signed-off-by: Daniel Walter <dwalter@google.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

net/sunrpc: replace strict_strto calls

Replace obsolete strict_strto calls with appropriate kstrto calls

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/scsi: replace strict_strto calls

Replace obsolete strict_strto with more appropriate kstrto calls

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/x86: replace strict_strto calls

Replace obsolete strict_strto calls with appropriate kstrto calls

Signed-off-by: Daniel Walter <dwalter@google.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/powerpc: replace obsolete strict_strto* calls

Replace strict_strto calls with more appropriate kstrto calls

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/arm/mach-w90x900/cpu.c: replace obsolete strict_strto

Replace obsolete strict_strto with kstrto calls

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/arm/mach-s3c24xx/mach-jive.c: replace strict_strto* with kstrto*

Replace obsolete strict_strto call with kstrto

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/arm/mach-pxa: replace strict_strto call with kstrto

Replace obsolete call to strict_strto with kstrto

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: Eric Miao <eric.y.miao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/arm/mach-omap2: replace strict_strto* with kstrto*

Replace obsolete strict_strto call with kstrto calls.
Simplify copy_from_user/strict_strto by using kstrto_from_user

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

init/main.c: code clean-up

Fixing some checkpatch warnings(remove global initialization, move
__initdata, coalesce formats ...)

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/gpio/gpio-zevio.c: fix build

Unbreak i386 allmodconfig.

This is a hack - please fix properly ;)

Cc: Fabian Vogt <fabian@ritter-vogt.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Merge branch 'akpm-current/current'

Merge branch 'rd-docs/master'

Merge remote-tracking branch 'aio/master'

Merge remote-tracking branch 'lzo-update/lzo-update'

Merge remote-tracking branch 'random/dev'

Merge remote-tracking branch 'clk/clk-next'

Merge remote-tracking branch 'ktest/for-next'

Merge remote-tracking branch 'userns/for-next'

Conflicts:
fs/btrfs/ioctl.c
fs/dcache.c
fs/namei.c
fs/namespace.c

Merge remote-tracking branch 'gpio/for-next'

Merge remote-tracking branch 'vhost/linux-next'

Conflicts:
drivers/vhost/net.c

Merge remote-tracking branch 'pinctrl/for-next'

Merge remote-tracking branch 'scsi/for-next'

Merge remote-tracking branch 'cgroup/for-next'

Merge remote-tracking branch 'char-misc/char-misc-next'

Conflicts:
drivers/w1/masters/mxc_w1.c

Merge remote-tracking branch 'staging/staging-next'

Merge remote-tracking branch 'usb/usb-next'

Merge remote-tracking branch 'driver-core/driver-core-next'

Merge remote-tracking branch 'workqueues/for-next'

Merge remote-tracking branch 'percpu/for-next'

Merge remote-tracking branch 'kvm/linux-next'

Merge remote-tracking branch 'rcu/rcu/next'

Merge remote-tracking branch 'irqchip/irqchip/for-next'

Merge remote-tracking branch 'edac-amd/for-next'

Merge remote-tracking branch 'edac/linux_next'

Merge remote-tracking branch 'tip/auto-latest'

Merge remote-tracking branch 'spi/for-next'

Merge remote-tracking branch 'devicetree/devicetree/next'

Merge remote-tracking branch 'audit/master'

Conflicts:
arch/mips/include/asm/syscall.h
arch/mips/kernel/ptrace.c
arch/x86/Kconfig
kernel/audit.c

Merge remote-tracking branch 'trivial/for-next'

Conflicts:
arch/arm/mach-msm/Kconfig

Merge remote-tracking branch 'iommu/next'

Merge remote-tracking branch 'selinux/next'

Merge remote-tracking branch 'security/next'

Merge remote-tracking branch 'regulator/for-next'

Merge remote-tracking branch 'omap_dss2/for-next'

Merge remote-tracking branch 'mfd-lj/for-mfd-next'

Merge remote-tracking branch 'slab/for-next'

Merge remote-tracking branch 'kgdb/kgdb-next'

Merge remote-tracking branch 'mmc-uh/next'

Merge remote-tracking branch 'device-mapper/for-next'

Merge remote-tracking branch 'block/for-next'

Merge remote-tracking branch 'sound-asoc/for-next'

Merge remote-tracking branch 'sound/for-next'

Merge remote-tracking branch 'drm-intel/for-linux-next'

Merge remote-tracking branch 'drm-panel/drm/panel/for-next'

Merge remote-tracking branch 'crypto/master'

Merge remote-tracking branch 'bluetooth/master'

Conflicts:
net/bluetooth/hci_conn.c
net/bluetooth/smp.c

Merge remote-tracking branch 'wireless-next/master'

Merge remote-tracking branch 'net-next/master'

Merge remote-tracking branch 'dmaengine/next'

Merge remote-tracking branch 'swiotlb/linux-next'

Merge remote-tracking branch 'ieee1394/for-next'

Merge remote-tracking branch 'pm/linux-next'

Merge remote-tracking branch 'libata/for-next'

Merge remote-tracking branch 'kbuild/for-next'

Merge remote-tracking branch 'v4l-dvb/master'

Merge remote-tracking branch 'hwmon-staging/hwmon-next'

Merge remote-tracking branch 'hid/for-next'

Merge remote-tracking branch 'vfs/for-next'

Merge remote-tracking branch 'xfs/for-next'

Merge remote-tracking branch 'nfs/linux-next'

Merge remote-tracking branch 'logfs/master'

Merge remote-tracking branch 'gfs2/master'

Merge remote-tracking branch 'fscache/fscache'

Merge remote-tracking branch 'f2fs/dev'