If a delayed or deferrable work is on stack we need to tell debug
objects that we are destroying the timer and the work. Otherwise we
leak the tracking object.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20140323141939.911487677@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull RCU update from Paul E. McKenney:
" [...] one late-breaking commit. This one was requested for 3.15 by Peter Zijlstra.
It is low risk because it adds a new in-kernel API with minimal changes to the
existing code. Those minimal changes are the addition of memory barriers and
ACCESS_ONCE() macro calls, neither of which should be able to break things.
This commit has passed significant rcutorture testing, with these additional
additions to rcutorture slated for 3.16. This commit has also been exposed to
-next testing. "
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Replace kfree_skb with dev_kfree_skb_any in vlan_insert_tag as
vlan_insert_tag can be called from hard irq context (netpoll)
and from other contexts.
dev_kfree_skb_any is used as vlan_insert_tag only frees the skb if the
skb can not be modified to insert a tag, in which case vlan_insert_tag
drops the skb.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Add a new clk_ops->debug_init method to allow a clock hardware
driver to populate the clock's debugfs directory with entries
beyond those common for every clock.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Pull networking fixes from David Miller:
1) OpenVswitch's lookup_datapath() returns error pointers, so don't
check against NULL. From Jiri Pirko.
2) pfkey_compile_policy() code path tries to do a GFP_KERNEL allocation
under RCU locks, fix by using GFP_ATOMIC when necessary. From
Nikolay Aleksandrov.
3) phy_suspend() indirectly passes uninitialized data into the ethtool
get wake-on-land implementations. Fix from Sebastian Hesselbarth.
4) CPSW driver unregisters CPTS twice, fix from Benedikt Spranger.
5) If SKB allocation of reply packet fails, vxlan's arp_reduce() defers
a NULL pointer. Fix from David Stevens.
6) IPV6 neigh handling in vxlan doesn't validate the destination
address properly, and it builds a packet with the src and dst
reversed. Fix also from David Stevens.
7) Fix spinlock recursion during subscription failures in TIPC stack,
from Erik Hugne.
8) Revert buggy conversion of davinci_emac to devm_request_irq, from
Chrstian Riesch.
9) Wrong flags passed into forwarding database netlink notifications,
from Nicolas Dichtel.
10) The netpoll neighbour soliciation handler checks wrong ethertype,
needs to be ETH_P_IPV6 rather than ETH_P_ARP. Fix from Li RongQing.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (34 commits)
tipc: fix spinlock recursion bug for failed subscriptions
vxlan: fix nonfunctional neigh_reduce()
net: davinci_emac: Fix rollback of emac_dev_open()
net: davinci_emac: Replace devm_request_irq with request_irq
netpoll: fix the skb check in pkt_is_ns
net: micrel : ks8851-ml: add vdd-supply support
ip6mr: fix mfc notification flags
ipmr: fix mfc notification flags
rtnetlink: fix fdb notification flags
tcp: syncookies: do not use getnstimeofday()
netlink: fix setsockopt in mmap examples in documentation
openvswitch: Correctly report flow used times for first 5 minutes after boot.
via-rhine: Disable device in error path
ATHEROS-ATL1E: Convert iounmap to pci_iounmap
vxlan: fix potential NULL dereference in arp_reduce()
cnic: Update version to 2.5.20 and copyright year.
cnic,bnx2i,bnx2fc: Fix inconsistent use of page size
cnic: Use proper ulp_ops for per device operations.
net: cdc_ncm: fix control message ordering
ipv6: ip6_append_data_mtu do not handle the mtu of the second fragment properly
...
Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time.
Reported-by: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
We were exposing a function based on kernel config options to userspace.
This is wrong. Move it to the audit internal header.
Suggested-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
It's not only for PCI devices any more, and the scope information for an
ACPI device provides the bus and devfn so that has to be stored here too.
It is the device pointer itself which needs to be protected with RCU,
so the __rcu annotation follows it into the definition of struct
dmar_dev_scope, since we're no longer just passing arrays of device
pointers around.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This adds rcu protected access to a queue in the nvme IOCTL path
to fix potential races between a surprise removal and queue usage in
nvme_submit_sync_cmd. The fix holds the rcu_read_lock() here to prevent
the nvme_queue from freeing while this path is executing so it can't
sleep, and so this path will no longer wait for a available command
id should they all be in use at the time a passthrough IOCTL request
is received.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
This adds rcu protected access to nvme_queue to fix a race between a
surprise removal freeing the queue and a thread with open reference on
a NVMe block device using that queue.
The queues do not need to be rcu protected during the initialization or
shutdown parts, so I've added a helper function for raw deferencing
to get around the sparse errors.
There is still a hole in the IOCTL path for the same problem, which is
fixed in a subsequent patch.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Summary of http://lkml.org/lkml/2014/3/14/363 :
Ted: module_param(queue_depth, int, 444)
Joe: 0444!
Rusty: User perms >= group perms >= other perms?
Joe: CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2?
Side effect of stricter permissions means removing the unnecessary
S_IFREG from several callers.
Note that the BUILD_BUG_ON_ZERO((perm) & 2) test was removed: a fair
number of drivers fail this test, so that will be the debate for a
future patch.
Suggested-by: Joe Perches <joe@perches.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> for drivers/pci/slot.c
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is the first batch of a much longer series of bug fixes
found during randconfig testing. This part are all the simple
patches that are applicable for the arm-soc tree, while most
other fixes will likely go through other maintainers.
* randconfig-fixes: (50 commits)
ARM: tegra: make debug_ll code build for ARMv6
ARM: sunxi: fix build for THUMB2_KERNEL
ARM: exynos: add missing include of linux/module.h
ARM: exynos: fix l2x0 saved regs handling
ARM: samsung: select CRC32 for SAMSUNG_PM_CHECK
ARM: samsung: select ATAGS where necessary
ARM: samsung: fix SAMSUNG_PM_DEBUG Kconfig logic
ARM: samsung: allow serial driver to be disabled
ARM: s5pv210: enable IDE support in MACH_TORBRECK
ARM: s5p64x0: fix building with only one soc type
ARM: s3c64xx: select power domains only when used
ARM: s3c64xx: MACH_SMDK6400 needs HSMMC1
ARM: s3c24xx: osiris dvs needs tps65010
ARM: s3c24xx: fix gta02 build error
ARM: s3c24xx: MINI2440 needs I2C for EEPROM_AT24
ARM: integrator: only select pl01x if TTY is enabled
ARM: realview: fix sparsemem build
ARM: footbridge: make screen_info setup conditional
ARM: footbridge: fix build with PCI disabled
ARM: footbridge: don't build floppy code for addin mode
...
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This patch adds a pair of new ioctls to the PTP Hardware Clock device
interface. Using the ioctls, user space programs can query each pin to
find out its current function and also reprogram a different function
if desired.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After the following commit:
commit b75ef8b44b
Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed Aug 10 15:18:39 2011 -0400
Tracepoint: Dissociate from module mutex
The following functions became unnecessary:
- tracepoint_probe_register_noupdate,
- tracepoint_probe_unregister_noupdate,
- tracepoint_probe_update_all.
In fact, none of the in-kernel tracers, nor LTTng, nor SystemTAP use
them. Remove those.
Moreover, the functions:
- tracepoint_iter_start,
- tracepoint_iter_next,
- tracepoint_iter_stop,
- tracepoint_iter_reset.
are unused by in-kernel tracers, LTTng and SystemTAP. Remove those too.
Link: http://lkml.kernel.org/r/1395379142-2118-2-git-send-email-mathieu.desnoyers@efficios.com
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The functions declared in include/linux/pxa2xx_ssp.h are
defined in plat-pxa/ssp.c, which can also be built for
PLAT_MMP, but may be disabled there. This can lead to
both unresolved symbols at link time and to duplicate
symbols at compile time for random configurations.
Changing the #ifdef in the header file to match the
Kconfig symbol that decides if the file is built solves
both problems.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Daniel Mack <zonque@gmail.com>
I originally wrote commit 35bb4399bd to shrink the size of the overhead of
tracepoints by several kilobytes. Later, I received a patch from Vaibhav
Nagarnaik that fixed a bug in the same code that this commit touches. Not
only did it fix a bug, it also removed code and shrunk the size of the
overhead of trace events even more than this commit did.
Since this commit is scheduled for 3.15 and Vaibhav's patch is already in
mainline, I need to revert this patch in order to keep it from conflicting
with Vaibhav's patch. Not to mention, Vaibhav's patch makes this patch
obsolete.
Link: http://lkml.kernel.org/r/20140320225637.0226041b@gandalf.local.home
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* acpi-processor:
ACPI: Move BAD_MADT_ENTRY() to linux/acpi.h
ACPI / processor: Make it possible to get APIC ID via GIC
ACPI / processor: Build idle_boot_override on x86 and ia64
ACPI / processor: Use ACPI_PROCESSOR_DEVICE_HID instead of "ACPI0007"
ACPI / processor: Fix acpi_processor_eval_pdc() return value type
It's almost identical to blk_mq_insert_request, so fold the two into one
slightly more generic function by making the flush special case a bit
smarted.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
The maximum number for irq routes is currently 1024, which is a bit on
the small size for s390: We support up to 4 x 64k virtual devices with
up to 64 queues, and we need one route for each of the queues if we want
to operate it via irqfd.
Let's bump this to 4k on s390 for now, as this at least covers the saner
setups.
We need to find a more general solution, though, as we can't just grow
the routing table indefinitly.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Introduce a new interrupt class for s390 adapter interrupts and enable
irqfds for s390.
This is depending on a new s390 specific vm capability, KVM_CAP_S390_IRQCHIP,
that needs to be enabled by userspace.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
array index in the trace event format bogus. He supplied an elegant solution
that uses __stringify() and also removes the need for the event_storage
and event_storage_mutex and also cuts off a few K of overhead from
the trace events.
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Merge tag 'trace-fixes-v3.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull trace fix from Steven Rostedt:
"Vaibhav Nagarnaik discovered that since 3.10 a clean-up patch made the
array index in the trace event format bogus.
He supplied an elegant solution that uses __stringify() and also
removes the need for the event_storage and event_storage_mutex and
also cuts off a few K of overhead from the trace events"
* tag 'trace-fixes-v3.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix array size mismatch in format string
Add remove_linear_migration_ptes_from_nonlinear(), to fix an interesting
little include/linux/swapops.h:131 BUG_ON(!PageLocked) found by trinity:
indicating that remove_migration_ptes() failed to find one of the
migration entries that was temporarily inserted.
The problem comes from remap_file_pages()'s switch from vma_interval_tree
(good for inserting the migration entry) to i_mmap_nonlinear list (no good
for locating it again); but can only be a problem if the remap_file_pages()
range does not cover the whole of the vma (zap_pte() clears the range).
remove_migration_ptes() needs a file_nonlinear method to go down the
i_mmap_nonlinear list, applying linear location to look for migration
entries in those vmas too, just in case there was this race.
The file_nonlinear method does need rmap_walk_control.arg to do this;
but it never needed vma passed in - vma comes from its own iteration.
Reported-and-tested-by: Dave Jones <davej@redhat.com>
Reported-and-tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following pattern is currently not well supported by RCU:
1. Make data element inaccessible to RCU readers.
2. Do work that probably lasts for more than one grace period.
3. Do something to make sure RCU readers in flight before #1 above
have completed.
Here are some things that could currently be done:
a. Do a synchronize_rcu() unconditionally at either #1 or #3 above.
This works, but imposes needless work and latency.
b. Post an RCU callback at #1 above that does a wakeup, then
wait for the wakeup at #3. This works well, but likely results
in an extra unneeded grace period. Open-coding this is also
a bit more semi-tricky code than would be good.
This commit therefore adds get_state_synchronize_rcu() and
cond_synchronize_rcu() APIs. Call get_state_synchronize_rcu() at #1
above and pass its return value to cond_synchronize_rcu() at #3 above.
This results in a call to synchronize_rcu() if no grace period has
elapsed between #1 and #3, but requires only a load, comparison, and
memory barrier if a full grace period did elapse.
Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Rename TAINT_UNSAFE_SMP to TAINT_CPU_OUT_OF_SPEC, so we can repurpose
the flag to encompass a wider range of pushing the CPU beyond its
warrany.
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Link: http://lkml.kernel.org/r/20140226154949.GA770@redhat.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
According to "Universal Serial Bus Communications Class Subclass
Specification for Mobile Broadband Interface Model, Revision 1.0,
Errata-1" published by USB-IF, the wMTU field of the MBIM extended
functional descriptor indicates the operator preferred MTU for IP data
streams.
This patch modifies cdc_ncm_setup to ensure that the MTU value set on
the usbnet device does not exceed the operator preferred MTU indicated
by wMTU if the MBIM device exposes a MBIM extended functional
descriptor.
Signed-off-by: Ben Chan <benchan@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Adds support for N-Port VFs, this includes:
1. Adding support in the wrapped FW command
In wrapped commands, we need to verify and convert
the slave's port into the real physical port.
Furthermore, when sending the response back to the slave,
a reverse conversion should be made.
2. Adjusting sqpn for QP1 para-virtualization
The slave assumes that sqpn is used for QP1 communication.
If the slave is assigned to a port != (first port), we need
to adjust the sqpn that will direct its QP1 packets into the
correct endpoint.
3. Adjusting gid[5] to modify the port for raw ethernet
In B0 steering, gid[5] contains the port. It needs
to be adjusted into the physical port.
4. Adjusting number of ports in the query / ports caps in the FW commands
When a slave queries the hardware, it needs to view only
the physical ports it's assigned to.
5. Adjusting the sched_qp according to the port number
The QP port is encoded in the sched_qp, thus in modify_qp we need
to encode the correct port in sched_qp.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the following utils:
1. Convert slave_id -> VF
2. Get the active ports by slave_id
3. Convert slave's port to real port
4. Get the slave's port from real port
5. Get all slaves that uses the i'th real port
6. Get all slaves that uses the i'th real port exclusively
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Adds the required data structures to support VFs with N (1 or 2)
ports instead of always using the number of physical ports.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
serial_s3c.h uses upf_t which is defined in serial_core.h but does not
include that itself meaning that users which include serial_s3c.h by
itself don't build.
Signed-off-by: Mark Brown <broonie@linaro.org>
[t.figa: Moved inclusion under #ifndef __ASSEMBLY__ to fix mach-exynos]
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
In event format strings, the array size is reported in two locations.
One in array subscript and then via the "size:" attribute. The values
reported there have a mismatch.
For e.g., in sched:sched_switch the prev_comm and next_comm character
arrays have subscript values as [32] where as the actual field size is
16.
name: sched_switch
ID: 301
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1;signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:char prev_comm[32]; offset:8; size:16; signed:1;
field:pid_t prev_pid; offset:24; size:4; signed:1;
field:int prev_prio; offset:28; size:4; signed:1;
field:long prev_state; offset:32; size:8; signed:1;
field:char next_comm[32]; offset:40; size:16; signed:1;
field:pid_t next_pid; offset:56; size:4; signed:1;
field:int next_prio; offset:60; size:4; signed:1;
After bisection, the following commit was blamed:
92edca0 tracing: Use direct field, type and system names
This commit removes the duplication of strings for field->name and
field->type assuming that all the strings passed in
__trace_define_field() are immutable. This is not true for arrays, where
the type string is created in event_storage variable and field->type for
all array fields points to event_storage.
Use __stringify() to create a string constant for the type string.
Also, get rid of event_storage and event_storage_mutex that are not
needed anymore.
also, an added benefit is that this reduces the overhead of events a bit more:
text data bss dec hex filename
8424787 2036472 1302528 11763787 b3804b vmlinux
8420814 2036408 1302528 11759750 b37086 vmlinux.patched
Link: http://lkml.kernel.org/r/1392349908-29685-1-git-send-email-vnagarnaik@google.com
Cc: Laurent Chavey <chavey@google.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
linux/compat.h does not include linux/unistd.h but the compat.h header
file contains various conditional
#ifdef __ARCH_WANT_COMPAT_...
asmlinkage long compat...()
#endif
compat system call function declarations.
If linux/unistd.h isn't included it depends on previous includes if those
__ARCH_WANT_COMPAT_... defines are defined or not. So add an additional
linux/unistd.h include.
Should fix this compile error on tile:
include/uapi/asm-generic/unistd.h:195:1: error: 'compat_sys_getdents64' undeclared
make[3]: *** [arch/tile/kernel/compat.o] Error 1
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
We accidentally declared pid_alive without any extern/inline connotation.
Some platforms were fine with this, some like ia64 and mips were very angry.
If the function is inline, the prototype should be inline!
on ia64:
include/linux/sched.h:1718: warning: 'pid_alive' declared inline after
being called
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Added the functions task_ppid_nr_ns() and task_ppid_nr() to abstract the lookup
of the PPID (real_parent's pid_t) of a process, including rcu locking, in the
arbitrary and init_pid_ns.
This provides an alternative to sys_getppid(), which is relative to the child
process' pid namespace.
(informed by ebiederman's 6c621b7e)
Cc: stable@vger.kernel.org
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
lib/audit.c provides a generic function for auditing system calls.
This patch extends it for compat syscall support on bi-architectures
(32/64-bit) by adding lib/compat_audit.c.
What is required to support this feature are:
* add asm/unistd32.h for compat system call names
* select CONFIG_AUDIT_ARCH_COMPAT_GENERIC
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
In perverse cases of file descriptor passing the current network
namespace of a process and the network namespace of a socket used by
that socket may differ. Therefore use the network namespace of the
appropiate socket to ensure replies always go to the appropiate
socket.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_notifier_register_done();
Fix the perf subsystem's hotplug notifier by using this latter form of
callback registration.
Also provide a bare-bones version of perf_cpu_notifier() that doesn't
invoke the notifiers for the already online CPUs. This would be useful
for subsystems that need to perform a different set of initialization
for the already online CPUs, or don't need the initialization altogether.
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The following method of CPU hotplug callback registration is not safe
due to the possibility of an ABBA deadlock involving the cpu_add_remove_lock
and the cpu_hotplug.lock.
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
The deadlock is shown below:
CPU 0 CPU 1
----- -----
Acquire cpu_hotplug.lock
[via get_online_cpus()]
CPU online/offline operation
takes cpu_add_remove_lock
[via cpu_maps_update_begin()]
Try to acquire
cpu_add_remove_lock
[via register_cpu_notifier()]
CPU online/offline operation
tries to acquire cpu_hotplug.lock
[via cpu_hotplug_begin()]
*** DEADLOCK! ***
The problem here is that callback registration takes the locks in one order
whereas the CPU hotplug operations take the same locks in the opposite order.
To avoid this issue and to provide a race-free method to register CPU hotplug
callbacks (along with initialization of already online CPUs), introduce new
variants of the callback registration APIs that simply register the callbacks
without holding the cpu_add_remove_lock during the registration. That way,
we can avoid the ABBA scenario. However, we will need to hold the
cpu_add_remove_lock throughout the entire critical section, to protect updates
to the callback/notifier chain.
This can be achieved by writing the callback registration code as follows:
cpu_maps_update_begin(); [ or cpu_notifier_register_begin(); see below ]
for_each_online_cpu(cpu)
init_cpu(cpu);
/* This doesn't take the cpu_add_remove_lock */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_maps_update_done(); [ or cpu_notifier_register_done(); see below ]
Note that we can't use get_online_cpus() here instead of cpu_maps_update_begin()
because the cpu_hotplug.lock is dropped during the invocation of CPU_POST_DEAD
notifiers, and hence get_online_cpus() cannot provide the necessary
synchronization to protect the callback/notifier chains against concurrent
reads and writes. On the other hand, since the cpu_add_remove_lock protects
the entire hotplug operation (including CPU_POST_DEAD), we can use
cpu_maps_update_begin/done() to guarantee proper synchronization.
Also, since cpu_maps_update_begin/done() is like a super-set of
get/put_online_cpus(), the former naturally protects the critical sections
from concurrent hotplug operations.
Since the names cpu_maps_update_begin/done() don't make much sense in CPU
hotplug callback registration scenarios, we'll introduce new APIs named
cpu_notifier_register_begin/done() and map them to cpu_maps_update_begin/done().
In summary, introduce the lockless variants of un/register_cpu_notifier() and
also export the cpu_notifier_register_begin/done() APIs for use by modules.
This way, we provide a race-free way to register hotplug callbacks as well as
perform initialization for the CPUs that are already online.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* pm-cpufreq: (30 commits)
intel_pstate: Set core to min P state during core offline
cpufreq: Add stop CPU callback to cpufreq_driver interface
cpufreq: Remove unnecessary braces
cpufreq: Fix checkpatch errors and warnings
cpufreq: powerpc: add cpufreq transition latency for FSL e500mc SoCs
cpufreq: remove unused notifier: CPUFREQ_{SUSPENDCHANGE|RESUMECHANGE}
cpufreq: Do not allow ->setpolicy drivers to provide ->target
cpufreq: arm_big_little: set 'physical_cluster' for each CPU
cpufreq: arm_big_little: make vexpress driver depend on bL core driver
cpufreq: SPEAr: Instantiate as platform_driver
cpufreq: Remove unnecessary variable/parameter 'frozen'
cpufreq: Remove cpufreq_generic_exit()
cpufreq: add 'freq_table' in struct cpufreq_policy
cpufreq: Reformat printk() statements
cpufreq: Tegra: Use cpufreq_generic_suspend()
cpufreq: s5pv210: Use cpufreq_generic_suspend()
cpufreq: exynos: Use cpufreq_generic_suspend()
cpufreq: Implement cpufreq_generic_suspend()
cpufreq: suspend governors on system suspend/hibernate
cpufreq: move call to __find_governor() to cpufreq_init_policy()
...
rjw> Why exactly are they errors?
Geert> checkpatch.pl says: "WARNING: please, no space before tabs",
Vim (with "let c_space_errors=1") shows them in red.
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There are only two users of get_nohz_timer_target(): timer and hrtimer. Both
call it under same circumstances, i.e.
#ifdef CONFIG_NO_HZ_COMMON
if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
return get_nohz_timer_target();
#endif
So, it makes more sense to get all this as part of get_nohz_timer_target()
instead of duplicating code at two places. For this another parameter is
required to be passed to this routine, pinned.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: fweisbec@gmail.com
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1e1b53537217d58d48c2d7a222a9c3ac47d5b64c.1395140107.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This callback allows the driver to do clean up before the CPU is
completely down and its state cannot be modified. This is used
by the intel_pstate driver to reduce the requested P state prior to
the core going away. This is required because the requested P state
of the offline core is used to select the package P state. This
effectively sets the floor package P state to the requested P state on
the offline core.
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
[rjw: Minor modifications]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
As of commit 45f0a85c82 ('PM / Runtime: Rework the "runtime idle"
helper routine'), the return value of ->runtime_idle() is no longer
ignored by the PM core, but used to decide whether to suspend the
device or not.
Update the documentation to match the code.
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
