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Davidlohr Bueso 11163348a2 oprofile: reduce mmap_sem hold for mm->exe_file 
sync_buffer() needs the mmap_sem for two distinct operations, both only
occurring upon user context switch handling:

 1) Dealing with the exe_file.

 2) Adding the dcookie data as we need to lookup the vma that
   backs it. This is done via add_sample() and add_data().

This patch isolates 1), for it will no longer need the mmap_sem for
serialization.  However, for now, make of the more standard
get_mm_exe_file(), requiring only holding the mmap_sem to read the value,
and relying on reference counting to make sure that the exe file won't
dissappear underneath us while doing the get dcookie.

As a consequence, for 2) we move the mmap_sem locking into where we really
need it, in lookup_dcookie().  The benefits are twofold: reduce mmap_sem
hold times, and cleaner code.

[akpm@linux-foundation.org: export get_mm_exe_file for arch/x86/oprofile/oprofile.ko]
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Robert Richter <rric@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-17 09:04:11 -04:00
..
accessibility
acpi Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
amba
android
ata Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
atm
auxdisplay
base power: wakeup: remove use of seq_printf return value 2015-04-15 16:35:24 -07:00
bcma
block Merge branch 'akpm' (patches from Andrew) 2015-04-15 16:39:15 -07:00
bluetooth Bluetooth: btusb: Use proper data structures for Intel vendor events 2015-04-09 10:42:18 +03:00
bus
cdrom
char Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-15 13:22:56 -07:00
clk clk: bcm/kona: use DIV_ROUND_CLOSEST_ULL() 2015-04-17 09:03:55 -04:00
clocksource
connector
coresight
cpufreq intel_pstate: Knights Landing support 2015-04-11 02:13:29 +02:00
cpuidle cpuidle: menu: use DIV_ROUND_CLOSEST_ULL() 2015-04-17 09:03:55 -04:00
crypto crypto: sahara - fix AES descriptor create 2015-04-08 22:20:06 +08:00
dca
devfreq
dio
dma sound updates for 4.1-rc1 2015-04-15 15:41:41 -07:00
dma-buf
edac
eisa
extcon
firewire
firmware Merge branch 'core-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-13 10:22:30 -07:00
fmc
gpio Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
gpu kernel.h: implement DIV_ROUND_CLOSEST_ULL 2015-04-17 09:03:55 -04:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2015-04-14 18:25:15 -07:00
hsi HSI: cmt_speech: fix error return code 2015-04-05 14:45:27 +02:00
hv
hwmon hwmon: (w83795) use find_closest_descending() in pwm_freq_to_reg() 2015-04-17 09:03:55 -04:00
hwspinlock
i2c Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
ide Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
idle Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
iio Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2015-04-14 09:50:27 -07:00
infiniband Merge branch 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-14 15:31:03 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2015-04-14 18:25:15 -07:00
iommu Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
ipack
irqchip irqchip core change for v4.1 (round 3) 2015-04-11 11:17:28 +02:00
isdn Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-04-15 09:00:47 -07:00
leds
lguest
macintosh
mailbox
mcb
md md/raid0: fix bug with chunksize not a power of 2. 2015-04-10 15:36:31 +10:00
media media: cxd2820r: use DIV_ROUND_CLOSEST_ULL() 2015-04-17 09:03:56 -04:00
memory
memstick memstick: mspro_block: add missing curly braces 2015-04-17 09:04:09 -04:00
message
mfd == Changes to existing drivers == 2015-04-14 17:29:55 -07:00
misc Merge branch 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-14 15:31:03 -07:00
mmc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2015-04-14 09:50:27 -07:00
mtd This pull request includes the following UBI/UBIFS changes: 2015-04-15 13:43:40 -07:00
net Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-15 13:22:56 -07:00
nfc NFC: logging neatening 2015-04-07 12:05:12 +02:00
ntb
nubus
of Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-04-15 09:00:47 -07:00
oprofile oprofile: reduce mmap_sem hold for mm->exe_file 2015-04-17 09:04:11 -04:00
parisc parisc: remove use of seq_printf return value 2015-04-15 16:35:25 -07:00
parport
pci PCI changes for the v4.1 merge window: 2015-04-13 15:45:47 -07:00
pcmcia
phy USB patches for 4.1-rc1 2015-04-13 17:07:21 -07:00
pinctrl This is the bulk of pin control changes for the v4.1 development 2015-04-14 17:58:15 -07:00
platform Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
pnp Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
power power: twl4030_madc_battery: Add missing MODULE_ALIAS 2015-04-06 19:39:57 +02:00
powercap powercap / RAPL: mark rapl_ids array as __initconst 2015-04-11 02:21:15 +02:00
pps
ps3
ptp
pwm
rapidio
ras
regulator == Changes to existing drivers == 2015-04-14 17:29:55 -07:00
remoteproc
reset
rpmsg
rtc rtc: use more standard kernel logging styles 2015-04-17 09:04:02 -04:00
s390 s390: remove use of seq_printf return value 2015-04-15 16:35:25 -07:00
sbus drivers/sbus/char/envctrl.c: ignore orderly_poweroff return value 2015-04-15 16:35:23 -07:00
scsi bfs: bfad_worker cleanup 2015-04-17 09:04:09 -04:00
sfi
sh
sn
soc
spi Merge remote-tracking branches 'spi/topic/spidev' and 'spi/topic/spidev-test' into spi-next 2015-04-11 23:09:31 +01:00
spmi
ssb ssb: add delay after PCI reset to fix SoC reboots 2015-04-07 20:18:10 +03:00
staging Merge branch 'akpm' (patches from Andrew) 2015-04-15 16:39:15 -07:00
target iscsi target: fix oops when adding reject pdu 2015-04-10 12:33:55 -07:00
tc
thermal drivers: thermal: st: remove several sparse warnings 2015-04-07 13:43:28 -07:00
thunderbolt
tty Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
uio
usb Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-15 13:22:56 -07:00
uwb
vfio vfio-pci: Fix use after free 2015-04-08 08:11:51 -06:00
vhost new helper: msg_data_left() 2015-04-11 15:53:35 -04:00
video == Changes to existing drivers == 2015-04-14 17:54:22 -07:00
virt
virtio
vlynq
vme
w1
watchdog Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2015-04-14 20:51:44 -07:00
xen cleancache: forbid overriding cleancache_ops 2015-04-14 16:49:03 -07:00
zorro
Kconfig
Makefile