Peter Zijlstra 54cf809b95 locking,qspinlock: Fix spin_is_locked() and spin_unlock_wait() ... Similar to commits: 51d7d5205d ("powerpc: Add smp_mb() to arch_spin_is_locked()") d86b8da04d ("arm64: spinlock: serialise spin_unlock_wait against concurrent lockers") qspinlock suffers from the fact that the _Q_LOCKED_VAL store is unordered inside the ACQUIRE of the lock. And while this is not a problem for the regular mutual exclusive critical section usage of spinlocks, it breaks creative locking like: spin_lock(A) spin_lock(B) spin_unlock_wait(B) if (!spin_is_locked(A)) do_something() do_something() In that both CPUs can end up running do_something at the same time, because our _Q_LOCKED_VAL store can drop past the spin_unlock_wait() spin_is_locked() loads (even on x86!!). To avoid making the normal case slower, add smp_mb()s to the less used spin_unlock_wait() / spin_is_locked() side of things to avoid this problem. Reported-and-tested-by: Davidlohr Bueso <dave@stgolabs.net> Reported-by: Giovanni Gherdovich <ggherdovich@suse.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org # v4.2 and later Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2016-05-20 19:30:32 -07:00
..
bitops	…
4level-fixup.h	…
Kbuild.asm	…
asm-offsets.h	…
atomic-long.h	…
atomic.h	…
atomic64.h	…
audit_change_attr.h	…
audit_dir_write.h	…
audit_read.h	…
audit_signal.h	…
audit_write.h	…
barrier.h	…
bitops.h	…
bitsperlong.h	…
bug.h	…
bugs.h	…
cache.h	…
cacheflush.h	…
checksum.h	…
clkdev.h	…
cmpxchg-local.h	…
cmpxchg.h	…
cputime.h	…
cputime_jiffies.h	…
cputime_nsecs.h	…
current.h	…
delay.h	…
device.h	…
div64.h	…
dma-contiguous.h	…
dma.h	…
early_ioremap.h	…
emergency-restart.h	…
exec.h	…
fb.h	…
fixmap.h	…
ftrace.h	…
futex.h	asm-generic/futex: Re-enable preemption in futex_atomic_cmpxchg_inatomic()	2016-04-21 11:06:09 +02:00
getorder.h	…
gpio.h	…
hardirq.h	…
hugetlb.h	…
hw_irq.h	…
ide_iops.h	…
int-ll64.h	…
io.h	io-64-nonatomic: Add relaxed accessor variants	2016-05-03 18:23:02 +01:00
ioctl.h	…
iomap.h	…
irq.h	…
irq_regs.h	…
irq_work.h	…
irqflags.h	…
kdebug.h	…
kmap_types.h	…
kvm_para.h	…
libata-portmap.h	…
linkage.h	…
local.h	…
local64.h	…
mcs_spinlock.h	…
memory_model.h	…
mm-arch-hooks.h	…
mm_hooks.h	…
mmu.h	…
mmu_context.h	…
module.h	…
msi.h	…
mutex-dec.h	…
mutex-null.h	…
mutex-xchg.h	…
mutex.h	…
page.h	…
param.h	…
parport.h	…
pci.h	…
pci_iomap.h	…
percpu.h	…
pgalloc.h	…
pgtable-nopmd.h	…
pgtable-nopud.h	…
pgtable.h	arch: fix has_transparent_hugepage()	2016-05-19 19:12:14 -07:00
preempt.h	…
ptrace.h	…
qrwlock.h	…
qrwlock_types.h	…
qspinlock.h	locking,qspinlock: Fix spin_is_locked() and spin_unlock_wait()	2016-05-20 19:30:32 -07:00
qspinlock_types.h	…
resource.h	…
rtc.h	…
rwsem.h	locking/rwsem: Introduce basis for down_write_killable()	2016-04-13 10:42:20 +02:00
seccomp.h	seccomp: Get compat syscalls from asm-generic header	2016-05-13 14:02:00 +02:00
sections.h	…
segment.h	…
serial.h	…
siginfo.h	SIGNAL: Move generic copy_siginfo() to signal.h	2016-05-13 14:02:10 +02:00
signal.h	…
simd.h	…
sizes.h	…
spinlock.h	…
statfs.h	…
string.h	…
switch_to.h	…
syscall.h	…
syscalls.h	…
termios-base.h	…
termios.h	…
timex.h	…
tlb.h	…
tlbflush.h	…
topology.h	…
trace_clock.h	…
uaccess-unaligned.h	…
uaccess.h	…
unaligned.h	…
unistd.h	…
user.h	…
vga.h	…
vmlinux.lds.h	x86/asm: Make sure verify_cpu() has a good stack	2016-04-13 11:52:19 +02:00
vtime.h	…
word-at-a-time.h	…
xor.h	…