Olof Johansson [Wed, 2 Nov 2011 11:00:49 +0000 (11:00 +0000)]
af_packet: de-inline some helper functions
This popped some compiler errors due to mismatched prototypes. Just
remove most manual inlines, the compiler should be able to figure out
what makes sense to inline and not.
net/packet/af_packet.c:252: warning: 'prb_curr_blk_in_use' declared inline after being called
net/packet/af_packet.c:252: warning: previous declaration of 'prb_curr_blk_in_use' was here
net/packet/af_packet.c:258: warning: 'prb_queue_frozen' declared inline after being called
net/packet/af_packet.c:258: warning: previous declaration of 'prb_queue_frozen' was here
net/packet/af_packet.c:248: warning: 'packet_previous_frame' declared inline after being called
net/packet/af_packet.c:248: warning: previous declaration of 'packet_previous_frame' was here
net/packet/af_packet.c:251: warning: 'packet_increment_head' declared inline after being called
net/packet/af_packet.c:251: warning: previous declaration of 'packet_increment_head' was here
Signed-off-by: Olof Johansson <olof@lixom.net> Cc: Chetan Loke <loke.chetan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Oliver Hartkopp [Wed, 2 Nov 2011 10:55:13 +0000 (10:55 +0000)]
MAINTAINERS: Add can-gw include to maintained files
Commit c1aabdf379bc2feeb0df7057ed5bad96f492133e (can-gw: add netlink based
CAN routing) added a new include file that's neither referenced by any of
the CAN maintainers.
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Tony Lindgren [Wed, 2 Nov 2011 13:40:28 +0000 (13:40 +0000)]
net: Add back alignment for size for __alloc_skb
Commit 87fb4b7b533073eeeaed0b6bf7c2328995f6c075 (net: more
accurate skb truesize) changed the alignment of size. This
can cause problems at least on some machines with NFS root:
Problem comes from commit 0e734419
(ipv4: Use inet_csk_route_child_sock() in DCCP and TCP.)
If inet_csk_route_child_sock() returns NULL, we should release socket
lock before freeing it.
Another lock imbalance exists if __inet_inherit_port() returns an error
since commit 093d282321da ( tproxy: fix hash locking issue when using
port redirection in __inet_inherit_port()) a backport is also needed for
>= 2.6.37 kernels.
Reported-by: Simon Kirby <sim@hostway.ca> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Tested-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Balazs Scheidler <bazsi@balabit.hu> CC: KOVACS Krisztian <hidden@balabit.hu> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Simon Kirby <sim@hostway.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Dumazet [Wed, 2 Nov 2011 22:47:44 +0000 (22:47 +0000)]
l2tp: fix race in l2tp_recv_dequeue()
Misha Labjuk reported panics occurring in l2tp_recv_dequeue()
If we release reorder_q.lock, we must not keep a dangling pointer (tmp),
since another thread could manipulate reorder_q.
Instead we must restart the scan at beginning of list.
Reported-by: Misha Labjuk <spiked.yar@gmail.com> Tested-by: Misha Labjuk <spiked.yar@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Josh Boyer [Thu, 3 Nov 2011 18:00:11 +0000 (16:00 -0200)]
edac: Only build sb_edac on 64-bit
The sb_edac driver is marginally useful on a 32-bit kernel, and
currently has 64-bit divide compile errors when building that config.
For now, make this build on only for 64-bit kernels.
Linus Torvalds [Thu, 3 Nov 2011 16:59:39 +0000 (09:59 -0700)]
Merge branch 'next' of git://github.com/kernelslacker/cpufreq
* 'next' of git://github.com/kernelslacker/cpufreq:
[CPUFREQ] db8500: support all frequencies
[CPUFREQ] db8500: remove unneeded for loop iteration over freq_table
[CPUFREQ] ARM Exynos4210 PM/Suspend compatibility with different bootloaders
[CPUFREQ] ARM: ux500: send cpufreq notification for all cpus
[CPUFREQ] e_powersaver: Allow user to lower maximum voltage
[CPUFREQ] e_powersaver: Check BIOS limit for CPU frequency
[CPUFREQ] e_powersaver: Additional checks
[CPUFREQ] exynos4210: Show list of available frequencies
Linus Torvalds [Thu, 3 Nov 2011 16:40:51 +0000 (09:40 -0700)]
Merge branch 'for-next' of git://git.infradead.org/users/sameo/mfd-2.6
* 'for-next' of git://git.infradead.org/users/sameo/mfd-2.6: (80 commits)
mfd: Fix missing abx500 header file updates
mfd: Add missing <linux/io.h> include to intel_msic
x86, mrst: add platform support for MSIC MFD driver
mfd: Expose TurnOnStatus in ab8500 sysfs
mfd: Remove support for early drop ab8500 chip
mfd: Add support for ab8500 v3.3
mfd: Add ab8500 interrupt disable hook
mfd: Convert db8500-prcmu panic() into pr_crit()
mfd: Refactor db8500-prcmu request_clock() function
mfd: Rename db8500-prcmu init function
mfd: Fix db5500-prcmu defines
mfd: db8500-prcmu voltage domain consumers additions
mfd: db8500-prcmu reset code retrieval
mfd: db8500-prcmu tweak for modem wakeup
mfd: Add db8500-pcmu watchdog accessor functions for watchdog
mfd: hwacc power state db8500-prcmu accessor
mfd: Add db8500-prcmu accessors for PLL and SGA clock
mfd: Move to the new db500 PRCMU API
mfd: Create a common interface for dbx500 PRCMU drivers
mfd: Initialize DB8500 PRCMU regs
...
Fix up trivial conflicts in
arch/arm/mach-imx/mach-mx31moboard.c
arch/arm/mach-omap2/board-omap3beagle.c
arch/arm/mach-u300/include/mach/irqs.h
drivers/mfd/wm831x-spi.c
Takashi Iwai [Thu, 3 Nov 2011 15:54:06 +0000 (16:54 +0100)]
ALSA: hda/realtek - Skip invalid digital out pins
Some BIOS report invalid pins as digital output pins. The driver checks
the connection but it doesn't do it fully correctly, and it leaves some
undefined value as the audio-out widget, which makes the driver spewing
warnings. This patch fixes the issue.
Linus Torvalds [Thu, 3 Nov 2011 15:22:06 +0000 (08:22 -0700)]
Merge branch 'sh-latest' of git://github.com/pmundt/linux-sh
* 'sh-latest' of git://github.com/pmundt/linux-sh:
sh: Add default uImage rule for sh7757lcr
sh: modify the asm/sh_eth.h to linux/sh_eth.h in sh7757lcr
sh: userimask.c needs linux/stat.h
sh: pfc: Add GPIO IRQ support
sh: modify the asm/sh_eth.h to linux/sh_eth.h in some boards
sh: pfc: Remove unused gpio_in_use member
sh: add parameters for EHCI and RIIC in clock-sh7757.c
sh: kexec: Add PHYSICAL_START
SH: irq: Remove IRQF_DISABLED
sh: pfc: get_config_reg() shift clean up
sh: intc: Add IRQ trigger bit field check
sh: drop unused Kconfig symbol
sh: Fix implicit declaration of function numa_node_id
sh: kexec: Register crashk_res
sh: ecovec: add renesas_usbhs DMAEngine support
Linus Torvalds [Thu, 3 Nov 2011 15:05:35 +0000 (08:05 -0700)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/hwspinlock
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/hwspinlock:
hwspinlock: add MAINTAINERS entries
hwspinlock/omap: omap_hwspinlock_remove should be __devexit
hwspinlock/u8500: add hwspinlock driver
hwspinlock/core: register a bank of hwspinlocks in a single API call
hwspinlock/core: remove stubs for register/unregister
hwspinlock/core: use a mutex to protect the radix tree
hwspinlock/core/omap: fix id issues on multiple hwspinlock devices
hwspinlock/omap: simplify allocation scheme
hwspinlock/core: simplify 'owner' handling
hwspinlock/core: simplify Kconfig
Fix up trivial conflicts (addition of omap_hwspinlock_pdata, removal of
omap_spinlock_latency) in arch/arm/mach-omap2/hwspinlock.c
Also, do an "evil merge" to fix a compile error in omap_hsmmc.c which
for some reason was reported in the same email thread as the "please
pull hwspinlock changes".
Linus Torvalds [Thu, 3 Nov 2011 14:53:22 +0000 (07:53 -0700)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
Revert "HID: multitouch: decide if hid-multitouch needs to handle mt devices"
HID: drivers/hid/hid-roccat.c: eliminate a null pointer dereference
HID: hid-apple: add device ID of another wireless aluminium
HID: Add device IDs for Macbook Pro 8 keyboards
It causes a resume regression for Andi on his Acer Aspire 1830T post
3.1. The screen just stays black after wakeup.
Also, it really looks like the wrong way to suspend and resume perf
events: I think they should be done as part of the CPU suspend and
resume, rather than as a notifier that does smp_call_function().
Reported-by: Andi Kleen <andi@firstfloor.org> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Wed, 2 Nov 2011 23:55:15 +0000 (16:55 -0700)]
Merge branch 'linux_next' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-edac
* 'linux_next' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-edac: (21 commits)
MAINTAINERS: add an entry for Edac Sandy Bridge driver
edac: tag sb_edac as EXPERIMENTAL, as it requires more testing
EDAC: Fix incorrect edac mode reporting in sb_edac
edac: sb_edac: Add it to the building system
edac: Add an experimental new driver to support Sandy Bridge CPU's
i7300_edac: Fix error cleanup logic
i7core_edac: Initialize memory name with cpu, channel, bank
i7core_edac: Fix compilation on 32 bits arch
i7core_edac: scrubbing fixups
EDAC: Correct Kconfig dependencies
i7core_edac: return -ENODEV if no MC is found
i7core_edac: use edac's own way to print errors
MAINTAINERS: remove dropped edac_mce.* from the file
i7core_edac: Drop the edac_mce facility
x86, MCE: Use notifier chain only for MCE decoding
EDAC i7core: Use mce socketid for better compatibility
i7core_edac: Don't enable memory scrubbing for Xeon 35xx
i7core_edac: Add scrubbing support
edac: Move edac main structs to include/linux/edac.h
i7core_edac: Fix oops when trying to inject errors
...
Linus Torvalds [Wed, 2 Nov 2011 23:52:17 +0000 (16:52 -0700)]
Merge branch 'misc-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux
* 'misc-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
MAINTAINERS: Update entry for IA64
[IA64] gpio: GENERIC_GPIO default must be n
[IA64[ add CONFIG_NET_VENDOR_INTEL=y to default config files where needed
[IA64] agp/hp-agp: Allow binding user memory to the AGP GART
[IA64] sn2: add missing put_cpu()
Linus Torvalds [Wed, 2 Nov 2011 23:07:27 +0000 (16:07 -0700)]
Merge branch 'akpm' (Andrew's incoming - part two)
Says Andrew:
"60 patches. That's good enough for -rc1 I guess. I have quite a lot
of detritus to be rechecked, work through maintainers, etc.
- most of the remains of MM
- rtc
- various misc
- cgroups
- memcg
- cpusets
- procfs
- ipc
- rapidio
- sysctl
- pps
- w1
- drivers/misc
- aio"
* akpm: (60 commits)
memcg: replace ss->id_lock with a rwlock
aio: allocate kiocbs in batches
drivers/misc/vmw_balloon.c: fix typo in code comment
drivers/misc/vmw_balloon.c: determine page allocation flag can_sleep outside loop
w1: disable irqs in critical section
drivers/w1/w1_int.c: multiple masters used same init_name
drivers/power/ds2780_battery.c: fix deadlock upon insertion and removal
drivers/power/ds2780_battery.c: add a nolock function to w1 interface
drivers/power/ds2780_battery.c: create central point for calling w1 interface
w1: ds2760 and ds2780, use ida for id and ida_simple_get() to get it
pps gpio client: add missing dependency
pps: new client driver using GPIO
pps: default echo function
include/linux/dma-mapping.h: add dma_zalloc_coherent()
sysctl: make CONFIG_SYSCTL_SYSCALL default to n
sysctl: add support for poll()
RapidIO: documentation update
drivers/net/rionet.c: fix ethernet address macros for LE platforms
RapidIO: fix potential null deref in rio_setup_device()
RapidIO: add mport driver for Tsi721 bridge
...
While back-porting Johannes Weiner's patch "mm: memcg-aware global
reclaim" for an internal effort, we noticed a significant performance
regression during page-reclaim heavy workloads due to high contention of
the ss->id_lock. This lock protects idr map, and serializes calls to
idr_get_next() in css_get_next() (which is used during the memcg hierarchy
walk).
Since idr_get_next() is just doing a look up, we need only serialize it
with respect to idr_remove()/idr_get_new(). By making the ss->id_lock a
rwlock, contention is greatly reduced and performance improves.
Tested: cat a 256m file from a ramdisk in a 128m container 50 times on
each core (one file + container per core) in parallel on a NUMA machine.
Result is the time for the test to complete in 1 of the containers.
Both kernels included Johannes' memcg-aware global reclaim patches.
Before rwlock patch: 1710.778s
After rwlock patch: 152.227s
Signed-off-by: Andrew Bresticker <abrestic@google.com> Cc: Paul Menage <menage@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jeff Moyer [Wed, 2 Nov 2011 20:40:10 +0000 (13:40 -0700)]
aio: allocate kiocbs in batches
In testing aio on a fast storage device, I found that the context lock
takes up a fair amount of cpu time in the I/O submission path. The reason
is that we take it for every I/O submitted (see __aio_get_req). Since we
know how many I/Os are passed to io_submit, we can preallocate the kiocbs
in batches, reducing the number of times we take and release the lock.
In my testing, I was able to reduce the amount of time spent in
_raw_spin_lock_irq by .56% (average of 3 runs). The command I used to
test this was:
I also tested the patch with various numbers of events passed to
io_submit, and I ran the xfstests aio group of tests to ensure I didn't
break anything.
Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Cc: Daniel Ehrenberg <dehrenberg@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Florian Faber [Wed, 2 Nov 2011 20:39:59 +0000 (13:39 -0700)]
drivers/w1/w1_int.c: multiple masters used same init_name
When using multiple masters, w1_int.c would use the .init_name from w1.c
for all entities, which will fail when creating a corresponding sysfs
entry. This patch uses the unique name previously generated.
---[ end trace 5a9233884fead918 ]---
kobject_add_internal failed for w1 bus master with -EEXIST, don't try to register things with the same name in the same directory.
James Nuss [Wed, 2 Nov 2011 20:39:38 +0000 (13:39 -0700)]
pps: new client driver using GPIO
This client driver allows you to use a GPIO pin as a source for PPS
signals. Platform data [1] are used to specify the GPIO pin number,
label, assert event edge type, and whether clear events are captured.
This driver is based on the work by Ricardo Martins who submitted an
initial implementation [2] of a PPS IRQ client driver to the linuxpps
mailing-list on Dec 3 2010.
James Nuss [Wed, 2 Nov 2011 20:39:34 +0000 (13:39 -0700)]
pps: default echo function
A default echo function has been provided so it is no longer an error when
you specify PPS_ECHOASSERT or PPS_ECHOCLEAR without an explicit echo
function. This allows some code re-use and also makes it easier to write
client drivers since the default echo function does not normally need to
change.
Signed-off-by: James Nuss <jamesnuss@nanometrics.ca> Reviewed-by: Ben Gardiner <bengardiner@nanometrics.ca> Acked-by: Rodolfo Giometti <giometti@linux.it> Cc: Ricardo Martins <rasm@fe.up.pt> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Igor Plyatov <plyatov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
WANG Cong [Wed, 2 Nov 2011 20:39:25 +0000 (13:39 -0700)]
sysctl: make CONFIG_SYSCTL_SYSCALL default to n
When I tried to send a patch to remove it, Andi told me we still need to
keep compabitlies for old libc, so we can't remove this completely. Then
just make it default to n and remove the doc from
feature-removal-schedule.txt.
Signed-off-by: WANG Cong <amwang@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Lucas De Marchi [Wed, 2 Nov 2011 20:39:22 +0000 (13:39 -0700)]
sysctl: add support for poll()
Adding support for poll() in sysctl fs allows userspace to receive
notifications of changes in sysctl entries. This adds a infrastructure to
allow files in sysctl fs to be pollable and implements it for hostname and
domainname.
[akpm@linux-foundation.org: s/declare/define/ for definitions] Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi> Cc: Greg KH <gregkh@suse.de> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add RapidIO mport driver for IDT TSI721 PCI Express-to-SRIO bridge device.
The driver provides full set of callback functions defined for mport
devices in RapidIO subsystem. It also is compatible with current version
of RIONET driver (Ethernet over RapidIO messaging services).
This patch is applicable to kernel versions starting from 2.6.39.
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com> Signed-off-by: Chul Kim <chul.kim@idt.com> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Li Yang <leoli@freescale.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Liu Gang [Wed, 2 Nov 2011 20:39:07 +0000 (13:39 -0700)]
arch/powerpc/sysdev/fsl_rio.c: release rapidio port I/O region resource if port failed to initialize
The "struct rio_mport" contains a member of master port I/O memory
resource structure "struct resource iores". This resource will be read
from device tree and be used for rapidio R/W transaction memory space.
Rapidio requests the port I/O memory resource under the root resource
"iomem_resource".
struct rio_mport *port;
port = kzalloc(sizeof(struct rio_mport), GFP_KERNEL);
request_resource(&iomem_resource, &port->iores);
When port failed to initialize, allocated "rio_mport" structure memory
will be freed, and the port I/O memory resource structure pointer
"&port->iores" will be invalid. If other requests resource under
"iomem_resource", "&port->iores" node may be operated in the child
resources list and this will cause the system to crash.
So the requested port I/O memory resource should be released before
freeing allocated "rio_mport" structure.
Signed-off-by: Liu Gang <Gang.Liu@freescale.com> Acked-by: Alexandre Bounine <alexandre.bounine@idt.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Liu Gang [Wed, 2 Nov 2011 20:39:05 +0000 (13:39 -0700)]
drivers/rapidio/rio-scan.c: use discovered bit to test if enumeration is complete
The discovered bit in PGCCSR register indicates if the device has been
discovered by system host. In Rapidio systems, some agent devices can also
be master devices. They can issue requests into the system.
Signed-off-by: Liu Gang <Gang.Liu@freescale.com> Acked-by: Alexandre Bounine <alexandre.bounine@idt.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Will Drewry [Wed, 2 Nov 2011 20:38:59 +0000 (13:38 -0700)]
init: add root=PARTUUID=UUID/PARTNROFF=%d support
Expand root=PARTUUID=UUID syntax to support selecting a root partition by
integer offset from a known, unique partition. This approach provides
similar properties to specifying a device and partition number, but using
the UUID as the unique path prior to evaluating the offset.
For example,
root=PARTUUID=99DE9194-FC15-4223-9192-FC243948F88B/PARTNROFF=1
selects the partition with UUID 99DE.. then select the next
partition.
This change is motivated by a particular usecase in Chromium OS where the
bootloader can easily determine what partition it is on (by UUID) but
doesn't perform general partition table walking.
That said, support for this model provides a direct mechanism for the user
to modify the root partition to boot without specifically needing to
extract each UUID or update the bootloader explicitly when the root
partition UUID is changed (if it is recreated to be larger, for instance).
Pinning to a /boot-style partition UUID allows the arbitrary root
partition reconfiguration/modifications with slightly less ambiguity than
just [dev][partition] and less stringency than the specific root partition
UUID.
[sfr@canb.auug.org.au: fix init sections warning] Signed-off-by: Will Drewry <wad@chromium.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Manfred Spraul [Wed, 2 Nov 2011 20:38:52 +0000 (13:38 -0700)]
ipc/sem.c: handle spurious wakeups
semtimedop() does not handle spurious wakeups, it returns -EINTR to user
space. Most other schedule() users would just loop and not return to user
space. The patch adds such a loop to semtimedop()
Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Manfred Spraul [Wed, 2 Nov 2011 20:38:50 +0000 (13:38 -0700)]
ipc/sem.c: fix return code race with semop vs. semop +semctl(IPC_RMID)
sys_semtimedop() may return -EIDRM although the semaphore operation
completed successfully:
thread 1: thread 2:
semtimedop(), sleeps
semop():
* acquires sem_lock()
semtimedop() woken up due to timeout
sem_lock() loops
* notices that thread 2 could be completed.
* performs the operations that thread 2 is sleeping on.
* marks the semaphore operation as IN_WAKEUP
* drops sem_lock(), does wakeup, sets return code to 0
* thread delayed due to interrupt, whatever
* returns to user space
* thread still delayed
semctl(IPC_RMID)
* acquires sem_lock()
* ipc_rmid(), ipcp->deleted=1
* drops sem_lock()
* thread finally continues - but seem_lock()
now fails due to ipcp->deleted == 1
* returns -EIDRM instead of 0
The fix is trivial: Always use the return code in queue.status.
In real world, the race probably doesn't matter:
If the semaphore array is destroyed, the app is probably not interested
if the last operation succeeded or was already cancelled.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vasiliy Kulikov [Wed, 2 Nov 2011 20:38:44 +0000 (13:38 -0700)]
proc: fix races against execve() of /proc/PID/fd**
fd* files are restricted to the task's owner, and other users may not get
direct access to them. But one may open any of these files and run any
setuid program, keeping opened file descriptors. As there are permission
checks on open(), but not on readdir() and read(), operations on the kept
file descriptors will not be checked. It makes it possible to violate
procfs permission model.
Reading fdinfo/* may disclosure current fds' position and flags, reading
directory contents of fdinfo/ and fd/ may disclosure the number of opened
files by the target task. This information is not sensible per se, but it
can reveal some private information (like length of a password stored in a
file) under certain conditions.
Used existing (un)lock_trace functions to check for ptrace_may_access(),
but instead of using EPERM return code from it use EACCES to be consistent
with existing proc_pid_follow_link()/proc_pid_readlink() return code. If
they differ, attacker can guess what fds exist by analyzing stat() return
code. Patched handlers: stat() for fd/*, stat() and read() for fdindo/*,
readdir() and lookup() for fd/ and fdinfo/.
David Rientjes [Wed, 2 Nov 2011 20:38:39 +0000 (13:38 -0700)]
cpusets: avoid looping when storing to mems_allowed if one node remains set
{get,put}_mems_allowed() exist so that general kernel code may locklessly
access a task's set of allowable nodes without having the chance that a
concurrent write will cause the nodemask to be empty on configurations
where MAX_NUMNODES > BITS_PER_LONG.
This could incur a significant delay, however, especially in low memory
conditions because the page allocator is blocking and reclaim requires
get_mems_allowed() itself. It is not atypical to see writes to
cpuset.mems take over 2 seconds to complete, for example. In low memory
conditions, this is problematic because it's one of the most imporant
times to change cpuset.mems in the first place!
The only way a task's set of allowable nodes may change is through cpusets
by writing to cpuset.mems and when attaching a task to a generic code is
not reading the nodemask with get_mems_allowed() at the same time, and
then clearing all the old nodes. This prevents the possibility that a
reader will see an empty nodemask at the same time the writer is storing a
new nodemask.
If at least one node remains unchanged, though, it's possible to simply
set all new nodes and then clear all the old nodes. Changing a task's
nodemask is protected by cgroup_mutex so it's guaranteed that two threads
are not changing the same task's nodemask at the same time, so the
nodemask is guaranteed to be stored before another thread changes it and
determines whether a node remains set or not.
Signed-off-by: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Paul Menage <paul@paulmenage.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Steven Rostedt [Wed, 2 Nov 2011 20:38:33 +0000 (13:38 -0700)]
memcg: Fix race condition in memcg_check_events() with this_cpu usage
Various code in memcontrol.c () calls this_cpu_read() on the calculations
to be done from two different percpu variables, or does an open-coded
read-modify-write on a single percpu variable.
Disable preemption throughout these operations so that the writes go to
the correct palces.
[hannes@cmpxchg.org: added this_cpu to __this_cpu conversion] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Greg Thelen <gthelen@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Wed, 2 Nov 2011 20:38:29 +0000 (13:38 -0700)]
memcg: close race between charge and putback
There is a potential race between a thread charging a page and another
thread putting it back to the LRU list:
charge: putback:
SetPageCgroupUsed SetPageLRU
PageLRU && add to memcg LRU PageCgroupUsed && add to memcg LRU
The order of setting one flag and checking the other is crucial, otherwise
the charge may observe !PageLRU while the putback observes !PageCgroupUsed
and the page is not linked to the memcg LRU at all.
Global memory pressure may fix this by trying to isolate and putback the
page for reclaim, where that putback would link it to the memcg LRU again.
Without that, the memory cgroup is undeletable due to a charge whose
physical page can not be found and moved out.
Signed-off-by: Johannes Weiner <jweiner@redhat.com> Cc: Ying Han <yinghan@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Wed, 2 Nov 2011 20:38:23 +0000 (13:38 -0700)]
memcg: skip scanning active lists based on individual size
Reclaim decides to skip scanning an active list when the corresponding
inactive list is above a certain size in comparison to leave the assumed
working set alone while there are still enough reclaim candidates around.
The memcg implementation of comparing those lists instead reports whether
the whole memcg is low on the requested type of inactive pages,
considering all nodes and zones.
This can lead to an oversized active list not being scanned because of the
state of the other lists in the memcg, as well as an active list being
scanned while its corresponding inactive list has enough pages.
Not only is this wrong, it's also a scalability hazard, because the global
memory state over all nodes and zones has to be gathered for each memcg
and zone scanned.
Make these calculations purely based on the size of the two LRU lists
that are actually affected by the outcome of the decision.
Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Igor Mammedov [Wed, 2 Nov 2011 20:38:21 +0000 (13:38 -0700)]
memcg: do not expose uninitialized mem_cgroup_per_node to world
If somebody is touching data too early, it might be easier to diagnose a
problem when dereferencing NULL at mem->info.nodeinfo[node] than trying to
understand why mem_cgroup_per_zone is [un|partly]initialized.
Signed-off-by: Igor Mammedov <imammedo@redhat.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Raghavendra K T [Wed, 2 Nov 2011 20:38:15 +0000 (13:38 -0700)]
memcg: rename mem variable to memcg
The memcg code sometimes uses "struct mem_cgroup *mem" and sometimes uses
"struct mem_cgroup *memcg". Rename all mem variables to memcg in source
file.
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Steven Rostedt [Wed, 2 Nov 2011 20:38:11 +0000 (13:38 -0700)]
cgroup/kmemleak: Annotate alloc_page() for cgroup allocations
When the cgroup base was allocated with kmalloc, it was necessary to
annotate the variable with kmemleak_not_leak(). But because it has
recently been changed to be allocated with alloc_page() (which skips
kmemleak checks) causes a warning on boot up.
I was triggering this output:
allocated 8388608 bytes of page_cgroup
please try 'cgroup_disable=memory' option if you don't want memory cgroups
kmemleak: Trying to color unknown object at 0xf5840000 as Grey
Pid: 0, comm: swapper Not tainted 3.0.0-test #12
Call Trace:
[<c17e34e6>] ? printk+0x1d/0x1f^M
[<c10e2941>] paint_ptr+0x4f/0x78
[<c178ab57>] kmemleak_not_leak+0x58/0x7d
[<c108ae9f>] ? __rcu_read_unlock+0x9/0x7d
[<c1cdb462>] kmemleak_init+0x19d/0x1e9
[<c1cbf771>] start_kernel+0x346/0x3ec
[<c1cbf1b4>] ? loglevel+0x18/0x18
[<c1cbf0aa>] i386_start_kernel+0xaa/0xb0
After a bit of debugging I tracked the object 0xf840000 (and others) down
to the cgroup code. The change from allocating base with kmalloc to
alloc_page() has the base not calling kmemleak_alloc() which adds the
pointer to the object_tree_root, but kmemleak_not_leak() adds it to the
crt_early_log[] table. On kmemleak_init(), the entry is found in the
early_log[] but not the object_tree_root, and this error message is
displayed.
If alloc_page() fails then it defaults back to vmalloc() which still uses
the kmemleak_alloc() which makes us still need the kmemleak_not_leak()
call. The solution is to call the kmemleak_alloc() directly if the
alloc_page() succeeds.
Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ben Blum [Wed, 2 Nov 2011 20:38:07 +0000 (13:38 -0700)]
cgroups: don't attach task to subsystem if migration failed
If a task has exited to the point it has called cgroup_exit() already,
then we can't migrate it to another cgroup anymore.
This can happen when we are attaching a task to a new cgroup between the
call to ->can_attach_task() on subsystems and the migration that is
eventually tried in cgroup_task_migrate().
In this case cgroup_task_migrate() returns -ESRCH and we don't want to
attach the task to the subsystems because the attachment to the new cgroup
itself failed.
Fix this by only calling ->attach_task() on the subsystems if the cgroup
migration succeeded.
Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ben Blum [Wed, 2 Nov 2011 20:38:05 +0000 (13:38 -0700)]
cgroups: more safe tasklist locking in cgroup_attach_proc
Fix unstable tasklist locking in cgroup_attach_proc.
According to this thread - https://lkml.org/lkml/2011/7/27/243 - RCU is
not sufficient to guarantee the tasklist is stable w.r.t. de_thread and
exit. Taking tasklist_lock for reading, instead of rcu_read_lock, ensures
proper exclusion.
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Clement Lecigne reports a filesystem which causes a kernel oops in
hfs_find_init() trying to dereference sb->ext_tree which is NULL.
This proves to be because the filesystem has a corrupted MDB extent
record, where the extents file does not fit into the first three extents
in the file record (the first blocks).
In hfs_get_block() when looking up the blocks for the extent file
(HFS_EXT_CNID), it fails the first blocks special case, and falls
through to the extent code (which ultimately calls hfs_find_init())
which is in the process of being initialised.
Hfs avoids this scenario by always having the extents b-tree fitting
into the first blocks (the extents B-tree can't have overflow extents).
The fix is to check at mount time that the B-tree fits into first
blocks, i.e. fail if HFS_I(inode)->alloc_blocks >=
HFS_I(inode)->first_blocks
Note, the existing commit 47f365eb57573 ("hfs: fix oops on mount with
corrupted btree extent records") becomes subsumed into this as a special
case, but only for the extents B-tree (HFS_EXT_CNID), it is perfectly
acceptable for the catalog B-Tree file to grow beyond three extents,
with the remaining extent descriptors in the extents overfow.
This fixes CVE-2011-2203
Reported-by: Clement LECIGNE <clement.lecigne@netasq.com> Signed-off-by: Phillip Lougher <plougher@redhat.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Namjae Jeon [Wed, 2 Nov 2011 20:38:00 +0000 (13:38 -0700)]
isofs: add readpages support
Use mpage_readpages() instead of multiple calls to isofs_readpage() to
reduce the CPU utilization and make performance higher.
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Anders [Wed, 2 Nov 2011 20:37:53 +0000 (13:37 -0700)]
rtc: add initial support for mcp7941x parts
Add initial support for the microchip mcp7941x series of real time clocks.
The mcp7941x series is generally compatible with the ds1307 and ds1337 rtc
devices from dallas semiconductor. minor differences include a backup
battery enable bit, and the polarity of the oscillator enable bit.
Signed-off-by: David Anders <danders.dev@gmail.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Reviewed-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since ramfs is hard-selected to "y", the module leftovers make no sense.
Signed-off-by: Richard Weinberger <richard@nod.at> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jiri Kosina [Wed, 2 Nov 2011 20:37:41 +0000 (13:37 -0700)]
binfmt_elf: fix PIE execution with randomization disabled
The case of address space randomization being disabled in runtime through
randomize_va_space sysctl is not treated properly in load_elf_binary(),
resulting in SIGKILL coming at exec() time for certain PIE-linked binaries
in case the randomization has been disabled at runtime prior to calling
exec().
Handle the randomize_va_space == 0 case the same way as if we were not
supporting .text randomization at all.
Based on original patch by H.J. Lu and Josh Boyer.
Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Ingo Molnar <mingo@elte.hu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: H.J. Lu <hongjiu.lu@intel.com> Cc: <stable@kernel.org> Tested-by: Josh Boyer <jwboyer@redhat.com> Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
s390 didn't return 0 in that case, if it's rolling back the *nr pointer it
should also return zero to avoid adding pages to the array at the wrong
offset.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
powerpc didn't return 0 in that case, if it's rolling back the *nr pointer
it should also return zero to avoid adding pages to the array at the wrong
offset.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: David Gibson <david@gibson.dropbear.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
powerpc: get_hugepte() don't put_page() the wrong page
"page" may have changed to point to the next hugepage after the loop
completed, The references have been taken on the head page, so the
put_page must happen there too.
This is a longstanding issue pre-thp inclusion.
It's totally unclear how these page_cache_add_speculative and
pte_val(pte) != pte_val(*ptep) checks are necessary across all the
powerpc gup_fast code, when x86 doesn't need any of that: there's no way
the page can be freed with irq disabled so we're guaranteed the
atomic_inc will happen on a page with page_count > 0 (so not needing the
speculative check).
The pte check is also meaningless on x86: no need to rollback on x86 if
the pte changed, because the pte can still change a CPU tick after the
check succeeded and it won't be rolled back in that case. The important
thing is we got a reference on a valid page that was mapped there a CPU
tick ago. So not knowing the soft tlb refill code of ppc64 in great
detail I'm not removing the "speculative" page_count increase and the
pte checks across all the code, but unless there's a strong reason for
it they should be later cleaned up too.
If a pte can change from huge to non-huge (like it could happen with
THP) passing a pte_t *ptep to gup_hugepte() would also require to repeat
the is_hugepd in gup_hugepte(), but that shouldn't happen with hugetlbfs
only so I'm not altering that.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
powerpc: remove superfluous PageTail checks on the pte gup_fast
This part of gup_fast doesn't seem capable of handling hugetlbfs ptes,
those should be handled by gup_hugepd only, so these checks are
superfluous.
Plus if this wasn't a noop, it would have oopsed because, the insistence
of using the speculative refcounting would trigger a VM_BUG_ON if a tail
page was encountered in the page_cache_get_speculative().
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michel while working on the working set estimation code, noticed that
calling get_page_unless_zero() on a random pfn_to_page(random_pfn)
wasn't safe, if the pfn ended up being a tail page of a transparent
hugepage under splitting by __split_huge_page_refcount().
He then found the problem could also theoretically materialize with
page_cache_get_speculative() during the speculative radix tree lookups
that uses get_page_unless_zero() in SMP if the radix tree page is freed
and reallocated and get_user_pages is called on it before
page_cache_get_speculative has a chance to call get_page_unless_zero().
So the best way to fix the problem is to keep page_tail->_count zero at
all times. This will guarantee that get_page_unless_zero() can never
succeed on any tail page. page_tail->_mapcount is guaranteed zero and
is unused for all tail pages of a compound page, so we can simply
account the tail page references there and transfer them to
tail_page->_count in __split_huge_page_refcount() (in addition to the
head_page->_mapcount).
While debugging this s/_count/_mapcount/ change I also noticed get_page is
called by direct-io.c on pages returned by get_user_pages. That wasn't
entirely safe because the two atomic_inc in get_page weren't atomic. As
opposed to other get_user_page users like secondary-MMU page fault to
establish the shadow pagetables would never call any superflous get_page
after get_user_page returns. It's safer to make get_page universally safe
for tail pages and to use get_page_foll() within follow_page (inside
get_user_pages()). get_page_foll() is safe to do the refcounting for tail
pages without taking any locks because it is run within PT lock protected
critical sections (PT lock for pte and page_table_lock for
pmd_trans_huge).
The standard get_page() as invoked by direct-io instead will now take
the compound_lock but still only for tail pages. The direct-io paths
are usually I/O bound and the compound_lock is per THP so very
finegrined, so there's no risk of scalability issues with it. A simple
direct-io benchmarks with all lockdep prove locking and spinlock
debugging infrastructure enabled shows identical performance and no
overhead. So it's worth it. Ideally direct-io should stop calling
get_page() on pages returned by get_user_pages(). The spinlock in
get_page() is already optimized away for no-THP builds but doing
get_page() on tail pages returned by GUP is generally a rare operation
and usually only run in I/O paths.
This new refcounting on page_tail->_mapcount in addition to avoiding new
RCU critical sections will also allow the working set estimation code to
work without any further complexity associated to the tail page
refcounting with THP.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Michel Lespinasse <walken@google.com> Reviewed-by: Michel Lespinasse <walken@google.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: <stable@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Wed, 2 Nov 2011 22:00:56 +0000 (15:00 -0700)]
Merge git://github.com/rustyrussell/linux
* git://github.com/rustyrussell/linux:
virtio-blk: use ida to allocate disk index
virtio: Add platform bus driver for memory mapped virtio device
virtio: Dont add "config" to list for !per_vq_vector
virtio: console: wait for first console port for early console output
virtio: console: add port stats for bytes received, sent and discarded
virtio: console: make discard_port_data() use get_inbuf()
virtio: console: rename variable
virtio: console: make get_inbuf() return port->inbuf if present
virtio: console: Fix return type for get_inbuf()
virtio: console: Use wait_event_freezable instead of _interruptible
virtio: console: Ignore port name update request if name already set
virtio: console: Fix indentation
virtio: modify vring_init and vring_size to take account of the layout containing *_event_idx
virtio.h: correct comment for struct virtio_driver
virtio-net: Use virtio_config_val() for retrieving config
virtio_config: Add virtio_config_val_len()
virtio-console: Use virtio_config_val() for retrieving config
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