Davidlohr Bueso cdea01b2bf blktrace: re-write setting q->blk_trace ...

This is really about simplifying the double xchg patterns into
a single cmpxchg, with the same logic. Other than the immediate
cleanup, there are some subtleties this change deals with:

(i) While the load of the old bt is fully ordered wrt everything,
ie:

        old_bt = xchg(&q->blk_trace, bt);             [barrier]
        if (old_bt)
	     (void) xchg(&q->blk_trace, old_bt);    [barrier]

blk_trace could still be changed between the xchg and the old_bt
load. Note that this description is merely theoretical and afaict
very small, but doing everything in a single context with cmpxchg
closes this potential race.

(ii) Ordering guarantees are obviously kept with cmpxchg.

(iii) Gets rid of the hacky-by-nature (void)xchg pattern.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
eviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

2015-10-30 05:25:59 +09:00

..

bpf

bpf: fix out of bounds access in verifier log

2015-09-09 14:11:55 -07:00

configs

kconfig: add xenconfig defconfig helper

2015-06-16 11:04:29 +01:00

debug

debug: prevent entering debug mode on panic/exception.

2015-02-19 12:39:03 -06:00

events

perf: Fix races in computing the header sizes

2015-09-18 09:20:26 +02:00

gcov

gcov: add support for GCC 5.1

2015-06-30 19:44:57 -07:00

irq

genirq: Fix race in register_irq_proc()

2015-10-01 12:18:13 +02:00

livepatch

livepatch: Improve error handling in klp_disable_func()

2015-07-14 22:48:06 +02:00

locking

locking/lockdep: Fix hlock->pin_count reset on lock stack rebuilds

2015-09-23 09:48:53 +02:00

power

Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block

2015-09-02 13:10:25 -07:00

printk

kexec: split kexec_load syscall from kexec core code

2015-09-10 13:29:01 -07:00

rcu

rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex

2015-09-20 21:01:22 -07:00

sched

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-09-27 12:50:27 -04:00

time

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-10-03 10:51:41 -04:00

trace

blktrace: re-write setting q->blk_trace

2015-10-30 05:25:59 +09:00

.gitignore

…

acct.c

acct: check FMODE_CAN_WRITE

2015-04-11 22:27:55 -04:00

async.c

kernel/async.c: switch to pr_foo()

2014-10-09 22:26:04 -04:00

audit_fsnotify.c

audit: clean simple fsnotify implementation

2015-08-06 16:14:53 -04:00

audit_tree.c

Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit

2015-09-08 13:34:59 -07:00

audit_watch.c

Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit

2015-09-08 13:34:59 -07:00

audit.c

Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit

2015-09-08 13:34:59 -07:00

audit.h

Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit

2015-09-08 13:34:59 -07:00

auditfilter.c

audit: implement audit by executable

2015-08-06 16:17:25 -04:00

auditsc.c

Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit

2015-09-08 13:34:59 -07:00

backtracetest.c

…

bounds.c

…

capability.c

kernel: conditionally support non-root users, groups and capabilities

2015-04-15 16:35:22 -07:00

cgroup_freezer.c

cgroup: allow a cgroup subsystem to reject a fork

2015-07-14 17:29:23 -04:00

cgroup_pids.c

cgroup: pids: fix invalid get/put usage

2015-08-25 14:19:25 -04:00

cgroup.c

Revert "sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem"

2015-09-16 11:51:12 -04:00

compat.c

compat: cleanup coding in compat_get_bitmap() and compat_put_bitmap()

2015-06-04 23:57:18 +02:00

configs.c

…

context_tracking.c

context_tracking: Inherit TIF_NOHZ through forks instead of context switches

2015-05-07 12:02:51 +02:00

cpu_pm.c

kernel/cpu_pm: fix cpu_cluster_pm_exit comment

2015-09-03 02:42:20 +02:00

cpu.c

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-08-31 20:26:22 -07:00

cpuset.c

cpuset: use trialcs->mems_allowed as a temp variable

2015-08-10 11:18:41 -04:00

crash_dump.c

…

cred.c

kernel/cred.c: remove unnecessary kdebug atomic reads

2015-09-10 13:29:01 -07:00

delayacct.c

…

dma.c

…

elfcore.c

…

exec_domain.c

Remove rest of exec domains.

2015-04-12 21:03:31 +02:00

exit.c

kernel: exit: fix typo in comment

2015-08-07 13:59:49 +02:00

extable.c

kernel/extable.c: remove duplicated include

2015-09-10 13:29:01 -07:00

fork.c

Revert "sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem"

2015-09-16 11:51:12 -04:00

freezer.c

freezer: remove obsolete comments in __thaw_task()

2014-10-21 23:44:20 +02:00

futex_compat.c

…

futex.c

futex: Make should_fail_futex() static

2015-07-20 21:43:54 +02:00

groups.c

kernel: conditionally support non-root users, groups and capabilities

2015-04-15 16:35:22 -07:00

hung_task.c

kernel/hung_task.c: change hung_task.c to use for_each_process_thread()

2015-04-15 16:35:22 -07:00

irq_work.c

percpu: Convert remaining __get_cpu_var uses in 3.18-rcX

2014-10-29 11:18:18 -04:00

jump_label.c

locking/static_keys: Add selftest

2015-08-03 11:34:16 +02:00

kallsyms.c

kernel/kallsyms.c: use __seq_open_private()

2014-10-14 02:18:16 +02:00

kcmp.c

…

Kconfig.freezer

…

Kconfig.hz

…

Kconfig.locks

locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS

2015-05-12 09:46:00 +02:00

Kconfig.preempt

…

kexec_core.c

kexec: export KERNEL_IMAGE_SIZE to vmcoreinfo

2015-09-10 13:29:01 -07:00

kexec_file.c

kexec: split kexec_file syscall code to kexec_file.c

2015-09-10 13:29:01 -07:00

kexec_internal.h

kexec: split kexec_file syscall code to kexec_file.c

2015-09-10 13:29:01 -07:00

kexec.c

kexec: split kexec_load syscall from kexec core code

2015-09-10 13:29:01 -07:00

kmod.c

kmod: handle UMH_WAIT_PROC from system unbound workqueue

2015-09-10 13:29:01 -07:00

kprobes.c

perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safe

2015-08-04 10:16:54 +02:00

ksysfs.c

kexec: split kexec_load syscall from kexec core code

2015-09-10 13:29:01 -07:00

kthread.c

kernel/kthread.c:kthread_create_on_node(): clarify documentation

2015-09-04 16:54:41 -07:00

latencytop.c

…

Makefile

sys_membarrier(): system-wide memory barrier (generic, x86)

2015-09-11 15:21:34 -07:00

membarrier.c

sys_membarrier(): system-wide memory barrier (generic, x86)

2015-09-11 15:21:34 -07:00

memremap.c

add devm_memremap_pages

2015-08-27 19:40:58 -04:00

module_signing.c

PKCS#7: Appropriately restrict authenticated attributes and content type

2015-08-12 17:01:01 +01:00

module-internal.h

…

module.c

module: weaken locking assertion for oops path.

2015-07-29 06:13:22 +09:30

notifier.c

Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-09-01 08:40:25 -07:00

nsproxy.c

bury struct proc_ns in fs/proc

2014-12-04 14:34:54 -05:00

padata.c

padata: use %*pb[l] to print bitmaps including cpumasks and nodemasks

2015-02-13 21:21:38 -08:00

panic.c

kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path

2015-06-30 19:44:57 -07:00

params.c

Minor merge needed, due to function move.

2015-07-01 10:49:25 -07:00

pid_namespace.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2014-12-16 15:53:03 -08:00

pid.c

rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()

2015-07-22 15:27:32 -07:00

profile.c

mm: rename alloc_pages_exact_node() to __alloc_pages_node()

2015-09-08 15:35:28 -07:00

ptrace.c

seccomp: add ptrace options for suspend/resume

2015-07-15 11:52:52 -07:00

range.c

kernel: avoid overflow in cmp_range

2015-01-17 10:02:23 +13:00

reboot.c

kexec: split kexec_load syscall from kexec core code

2015-09-10 13:29:01 -07:00

relay.c

kernel/relay.c: use kvfree() in relay_free_page_array()

2015-06-30 19:44:59 -07:00

resource.c

mm: enhance region_is_ram() to region_intersects()

2015-08-10 23:07:05 -04:00

seccomp.c

Merge tag 'seccomp-next' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into next

2015-07-20 17:19:19 +10:00

signal.c

signal: fix information leak in copy_siginfo_to_user

2015-08-07 04:39:40 +03:00

smp.c

smp: Fix error case handling in smp_call_function_*()

2015-04-19 13:19:23 -07:00

smpboot.c

smpboot: allow passing the cpumask on per-cpu thread registration

2015-09-04 16:54:41 -07:00

smpboot.h

…

softirq.c

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-02-09 15:24:03 -08:00

stacktrace.c

stacktrace: introduce snprint_stack_trace for buffer output

2014-12-13 12:42:48 -08:00

stop_machine.c

stop_machine: Remove cpu_stop_work's from list in cpu_stop_park()

2015-08-03 12:21:28 +02:00

sys_ni.c

sys_membarrier(): system-wide memory barrier (generic, x86)

2015-09-11 15:21:34 -07:00

sys.c

vfs: Commit to never having exectuables on proc and sysfs.

2015-07-10 10:39:25 -05:00

sysctl_binary.c

kernel: add panic_on_warn

2014-12-10 17:41:10 -08:00

sysctl.c

sysctl: fix int -> unsigned long assignments in INT_MIN case

2015-09-10 13:29:01 -07:00

task_work.c

task_work: remove fifo ordering guarantee

2015-09-05 13:46:58 -07:00

taskstats.c

netlink: make nlmsg_end() and genlmsg_end() void

2015-01-18 01:03:45 -05:00

test_kprobes.c

…

torture.c

rcu: Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()

2015-05-27 12:56:15 -07:00

tracepoint.c

…

tsacct.c

…

uid16.c

groups: Consolidate the setgroups permission checks

2014-12-05 17:19:27 -06:00

up.c

…

user_namespace.c

capabilities: ambient capabilities

2015-09-04 16:54:41 -07:00

user-return-notifier.c

…

user.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2014-12-17 12:31:40 -08:00

utsname_sysctl.c

…

utsname.c

copy address of proc_ns_ops into ns_common

2014-12-04 14:34:47 -05:00

watchdog.c

watchdog: rename watchdog_suspend() and watchdog_resume()

2015-09-04 16:54:41 -07:00

workqueue_internal.h

…

workqueue.c

Merge branch 'for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2015-09-02 08:02:20 -07:00