726328d92a
This patch updates/fixes all spin_unlock_wait() implementations. The update is in semantics; where it previously was only a control dependency, we now upgrade to a full load-acquire to match the store-release from the spin_unlock() we waited on. This ensures that when spin_unlock_wait() returns, we're guaranteed to observe the full critical section we waited on. This fixes a number of spin_unlock_wait() users that (not unreasonably) rely on this. I also fixed a number of ticket lock versions to only wait on the current lock holder, instead of for a full unlock, as this is sufficient. Furthermore; again for ticket locks; I added an smp_rmb() in between the initial ticket load and the spin loop testing the current value because I could not convince myself the address dependency is sufficient, esp. if the loads are of different sizes. I'm more than happy to remove this smp_rmb() again if people are certain the address dependency does indeed work as expected. Note: PPC32 will be fixed independently Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: chris@zankel.net Cc: cmetcalf@mellanox.com Cc: davem@davemloft.net Cc: dhowells@redhat.com Cc: james.hogan@imgtec.com Cc: jejb@parisc-linux.org Cc: linux@armlinux.org.uk Cc: mpe@ellerman.id.au Cc: ralf@linux-mips.org Cc: realmz6@gmail.com Cc: rkuo@codeaurora.org Cc: rth@twiddle.net Cc: schwidefsky@de.ibm.com Cc: tony.luck@intel.com Cc: vgupta@synopsys.com Cc: ysato@users.sourceforge.jp Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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.. | ||
asm-offsets.h | ||
atomic.h | ||
bitops.h | ||
cache.h | ||
cacheflush.h | ||
checksum.h | ||
cmpxchg.h | ||
delay.h | ||
dma-mapping.h | ||
dma.h | ||
elf.h | ||
exec.h | ||
fixmap.h | ||
fpu.h | ||
futex.h | ||
hexagon_vm.h | ||
intrinsics.h | ||
io.h | ||
irq.h | ||
irqflags.h | ||
Kbuild | ||
kgdb.h | ||
linkage.h | ||
mem-layout.h | ||
mmu_context.h | ||
mmu.h | ||
module.h | ||
mutex.h | ||
page.h | ||
perf_event.h | ||
pgalloc.h | ||
pgtable.h | ||
processor.h | ||
smp.h | ||
spinlock_types.h | ||
spinlock.h | ||
string.h | ||
suspend.h | ||
switch_to.h | ||
syscall.h | ||
thread_info.h | ||
time.h | ||
timer-regs.h | ||
timex.h | ||
tlb.h | ||
tlbflush.h | ||
traps.h | ||
uaccess.h | ||
vdso.h | ||
vm_fault.h | ||
vm_mmu.h |