In patch:
"rcu: Add transitivity to remaining rcu_node ->lock acquisitions"
All locking operations on rcu_node::lock are replaced with the wrappers
because of the need of transitivity, which indicates we should never
write code using LOCK primitives alone(i.e. without a proper barrier
following) on rcu_node::lock outside those wrappers. We could detect
this kind of misuses on rcu_node::lock in the future by adding __private
modifier on rcu_node::lock.
To privatize rcu_node::lock, unlock wrappers are also needed. Replacing
spinlock unlocks with these wrappers not only privatizes rcu_node::lock
but also makes it easier to figure out critical sections of rcu_node.
This patch adds __private modifier to rcu_node::lock and makes every
access to it wrapped by ACCESS_PRIVATE(). Besides, unlock wrappers are
added and raw_spin_unlock(&rnp->lock) and its friends are replaced with
those wrappers.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
In C programming language, we don't have a easy way to privatize a
member of a structure. However in kernel, sometimes there is a need to
privatize a member in case of potential bugs or misuses.
Fortunately, the noderef attribute of sparse is a way to privatize a
member, as by defining a member as noderef, the address-of operator on
the member will produce a noderef pointer to that member, and if anyone
wants to dereference that kind of pointers to read or modify the member,
sparse will yell.
Based on this, __private modifier and related operation ACCESS_PRIVATE()
are introduced, which could help detect undesigned public uses of
private members of structs. Here is an example of sparse's output if it
detect an undersigned public use:
| kernel/rcu/tree.c:4453:25: warning: incorrect type in argument 1 (different modifiers)
| kernel/rcu/tree.c:4453:25: expected struct raw_spinlock [usertype] *lock
| kernel/rcu/tree.c:4453:25: got struct raw_spinlock [noderef] *<noident>
Also, this patch improves compiler.h a little bit by adding comments for
"#else" and "#endif".
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The related warning from gcc 6.0:
In file included from kernel/rcu/tree.c:4630:0:
kernel/rcu/tree_plugin.h:810:40: warning: ‘rcu_data_p’ defined but not used [-Wunused-const-variable]
static struct rcu_data __percpu *const rcu_data_p = &rcu_sched_data;
^~~~~~~~~~
Also remove always redundant rcu_data_p in tree.c.
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The "Disabled dynamic grace-period expediting" console message is
currently printed unconditionally. This commit causes it to be
output only when it is impossible to switch between normal and
expedited grace periods, which was the original intent.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Commit #e3663b1024d1 ("rcu: Handle gpnum/completed wrap while dyntick
idle") sets rdp->gpwrap on the wrong side of the "if" statement in
dyntick_save_progress_counter(), that is, it sets it when the CPU is
not idle instead of when it is idle. Of course, if the CPU is not idle,
its rdp->gpnum won't be lagging beind the global rsp->gpnum, which means
that rdp->gpwrap will never be set.
This commit therefore moves this code to the proper leg of that "if"
statement. This change means that the "else" cause is just "return 0"
and the "then" clause ends with "return 1", so also move the "return 0"
to follow the "if", dropping the "else" clause.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Commit 4a81e8328d ("Reduce overhead of cond_resched() checks for RCU")
handles the error case where a nohz_full loops indefinitely in the kernel
with the scheduling-clock interrupt disabled. However, this handling
includes IPIing the CPU running the offending loop, which is not what
we want for real-time workloads. And there are starting to be real-time
CPU-bound in-kernel workloads, and these must be handled without IPIing
the CPU, at least not in the common case. Therefore, this situation can
no longer be dismissed as an error case.
This commit therefore splits the handling out, so that the setting of
bits in the per-CPU rcu_sched_qs_mask variable is done relatively early,
but if the problem persists, resched_cpu() is eventually used to IPI the
CPU containing the offending loop. Assuming that in-kernel CPU-bound
loops used by real-time tasks contain frequent calls cond_resched_rcu_qs()
(as in more than once per few tens of milliseconds), the real-time tasks
will never be IPIed.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
The header comment for rcu_report_qs_rsp() was obsolete, dating well
before the advent of RCU grace-period kthreads. This commit therefore
brings this comment back into alignment with current reality.
Reported-by: Lihao Liang <lihao.liang@cs.ox.ac.uk>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
A zero seems to have escaped earlier true/false substitution efforts,
so this commit changes 0 to false for the ->core_needs_qs boolean field.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Pull MIPS updates from Ralf Baechle:
"This is the main pull request for MIPS for 4.5 plus some 4.4 fixes.
The executive summary:
- ATH79 platform improvments, use DT bindings for the ATH79 USB PHY.
- Avoid useless rebuilds for zboot.
- jz4780: Add NEMC, BCH and NAND device tree nodes
- Initial support for the MicroChip's DT platform. As all the device
drivers are missing this is still of limited use.
- Some Loongson3 cleanups.
- The unavoidable whitespace polishing.
- Reduce clock skew when synchronizing the CPU cycle counters on CPU
startup.
- Add MIPS R6 fixes.
- Lots of cleanups across arch/mips as fallout from KVM.
- Lots of minor fixes and changes for IEEE 754-2008 support to the
FPU emulator / fp-assist software.
- Minor Ralink, BCM47xx and bcm963xx platform support improvments.
- Support SMP on BCM63168"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (84 commits)
MIPS: zboot: Add support for serial debug using the PROM
MIPS: zboot: Avoid useless rebuilds
MIPS: BMIPS: Enable ARCH_WANT_OPTIONAL_GPIOLIB
MIPS: bcm63xx: nvram: Remove unused bcm63xx_nvram_get_psi_size() function
MIPS: bcm963xx: Update bcm_tag field image_sequence
MIPS: bcm963xx: Move extended flash address to bcm_tag header file
MIPS: bcm963xx: Move Broadcom BCM963xx image tag data structure
MIPS: bcm63xx: nvram: Use nvram structure definition from header file
MIPS: bcm963xx: Add Broadcom BCM963xx board nvram data structure
MAINTAINERS: Add KVM for MIPS entry
MIPS: KVM: Add missing newline to kvm_err()
MIPS: Move KVM specific opcodes into asm/inst.h
MIPS: KVM: Use cacheops.h definitions
MIPS: Break down cacheops.h definitions
MIPS: Use EXCCODE_ constants with set_except_vector()
MIPS: Update trap codes
MIPS: Move Cause.ExcCode trap codes to mipsregs.h
MIPS: KVM: Make kvm_mips_{init,exit}() static
MIPS: KVM: Refactor added offsetof()s
MIPS: KVM: Convert EXPORT_SYMBOL to _GPL
...
Pull x86 platform driver updates from Darren Hart:
"Emergency travel prevented me from completing my final testing on this
until today. Nothing here that couldn't wait until RC1 fixes, but I
thought it best to get it out sooner rather than later as it does
contain a build warning fix.
Summary:
A build warning fix, MAINTAINERS cleanup, and a new DMI quirk:
ideapad-laptop:
- Add Lenovo Yoga 700 to no_hw_rfkill dmi list
MAINTAINERS:
- Combine multiple telemetry entries
intel_telemetry_debugfs:
- Fix unused warnings in telemetry debugfs"
* tag 'platform-drivers-x86-v4.5-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
ideapad-laptop: Add Lenovo Yoga 700 to no_hw_rfkill dmi list
MAINTAINERS: Combine multiple telemetry entries
intel_telemetry_debugfs: Fix unused warnings in telemetry debugfs
Pull thermal management updates from Zhang Rui:
"The top merge commit was re-generated yesterday because two topic
branches were dropped from this pull request in the last minute due to
some unaddressed comments. All the other material has been in
linux-next for quite a while.
Specifics:
- Enhance thermal core to handle unexpected device cooling states
after fresh boot and system resume. From Zhang Rui and Chen Yu.
- Several fixes and cleanups on Rockchip and RCAR thermal drivers.
From Caesar Wang and Kuninori Morimoto.
- Add Broxton support for Intel processor thermal reporting device
driver. From Amy Wiles"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
thermal: trip_point_temp_store() calls thermal_zone_device_update()
thermal: rcar: rcar_thermal_get_temp() return error if strange temp
thermal: rcar: check irq possibility in rcar_thermal_irq_xxx()
thermal: rcar: check every rcar_thermal_update_temp() return value
thermal: rcar: move rcar_thermal_dt_ids to upside
thermal: rockchip: Support the RK3399 SoCs in thermal driver
thermal: rockchip: Support the RK3228 SoCs in thermal driver
dt-bindings: rockchip-thermal: Support the RK3228/RK3399 SoCs compatible
thermal: rockchip: fix a trivial typo
Thermal: Enable Broxton SoC thermal reporting device
thermal: constify pch_dev_ops structure
Thermal: do thermal zone update after a cooling device registered
Thermal: handle thermal zone device properly during system sleep
Thermal: initialize thermal zone device correctly
Pull 9p updates from Eric Van Hensbergen:
"Sorry for the last minute pull request, there's was a change that
didn't get pulled into for-next until two weeks ago and I wanted to
give it some bake time.
Summary:
Rework and error handling fixes, primarily in the fscatch and fd
transports"
* tag 'for-linus-4.5-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
fs/9p: use fscache mutex rather than spinlock
9p: trans_fd, bail out if recv fcall if missing
9p: trans_fd, read rework to use p9_parse_header
net/9p: Add device name details on error
Pull Ceph updates from Sage Weil:
"The two main changes are aio support in CephFS, and a series that
fixes several issues in the authentication key timeout/renewal code.
On top of that are a variety of cleanups and minor bug fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
libceph: remove outdated comment
libceph: kill off ceph_x_ticket_handler::validity
libceph: invalidate AUTH in addition to a service ticket
libceph: fix authorizer invalidation, take 2
libceph: clear messenger auth_retry flag if we fault
libceph: fix ceph_msg_revoke()
libceph: use list_for_each_entry_safe
ceph: use i_size_{read,write} to get/set i_size
ceph: re-send AIO write request when getting -EOLDSNAP error
ceph: Asynchronous IO support
ceph: Avoid to propagate the invalid page point
ceph: fix double page_unlock() in page_mkwrite()
rbd: delete an unnecessary check before rbd_dev_destroy()
libceph: use list_next_entry instead of list_entry_next
ceph: ceph_frag_contains_value can be boolean
ceph: remove unused functions in ceph_frag.h
Pull SMB3 fixes from Steve French:
"A collection of CIFS/SMB3 fixes.
It includes a couple bug fixes, a few for improved debugging of
cifs.ko and some improvements to the way cifs does key generation.
I do have some additional bug fixes I expect in the next week or two
(to address a problem found by xfstest, and some fixes for SMB3.11
dialect, and a couple patches that just came in yesterday that I am
reviewing)"
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
cifs_dbg() outputs an uninitialized buffer in cifs_readdir()
cifs: fix race between call_async() and reconnect()
Prepare for encryption support (first part). Add decryption and encryption key generation. Thanks to Metze for helping with this.
cifs: Allow using O_DIRECT with cache=loose
cifs: Make echo interval tunable
cifs: Check uniqueid for SMB2+ and return -ESTALE if necessary
Print IP address of unresponsive server
cifs: Ratelimit kernel log messages
This patch fixes compile time warnings when CONFIG_PM_SLEEP
is undefined. In this case sleep related counters are unused.
Signed-off-by: Souvik Kumar Chakravarty <souvik.k.chakravarty@intel.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
If we detect that there is nothing to do just set the flag and do not
check if it was already set before. Races really do not matter. If the
flag is set by any code then the shepherd will start dealing with the
situation and reenable the vmstat workers when necessary again.
Since commit 0eb77e9880 ("vmstat: make vmstat_updater deferrable again
and shut down on idle") quiet_vmstat might update cpu_stat_off and mark
a particular cpu to be handled by vmstat_shepherd. This might trigger a
VM_BUG_ON in vmstat_update because the work item might have been
sleeping during the idle period and see the cpu_stat_off updated after
the wake up. The VM_BUG_ON is therefore misleading and no more
appropriate. Moreover it doesn't really suite any protection from real
bugs because vmstat_shepherd will simply reschedule the vmstat_work
anytime it sees a particular cpu set or vmstat_update would do the same
from the worker context directly. Even when the two would race the
result wouldn't be incorrect as the counters update is fully idempotent.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Boqun Feng
Chen Gang
Paul E. McKenney
Linus Torvalds
Josh Boyer
Souvik Kumar Chakravarty
Christoph Lameter
Ralf Baechle
Alban Bedel
Florian Fainelli
Simon Arlott