diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2020-12-17 23:47:28 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-02-09 01:09:44 +1100 |
| commit | 780de40601aabeca41bc9aa717a329a77aa85e1a (patch) | |
| tree | f507cbc288fd168cd062c5c433de14d95a1cc0cf /arch/powerpc/mm | |
| parent | 54bb503345b81399575e2b7a3a6497ae212ad827 (diff) | |
powerpc/64s/radix: Allow mm_cpumask trimming from external sources
mm_cpumask trimming is currently restricted to be issued by the current
thread of a single-threaded mm. This patch relaxes that and allows the
mask to be trimmed from any context.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201217134731.488135-5-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/book3s64/radix_tlb.c | 16 |
1 files changed, 6 insertions, 10 deletions
diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c index 3d8b494c39f6..c27ef2ff8950 100644 --- a/arch/powerpc/mm/book3s64/radix_tlb.c +++ b/arch/powerpc/mm/book3s64/radix_tlb.c @@ -666,20 +666,16 @@ static void do_exit_flush_lazy_tlb(void *arg) } /* - * This IPI is only initiated from a CPU which is running mm which - * is a single-threaded process, so there will not be another racing - * IPI coming in where we would find our cpumask already clear. - * - * Nothing else clears our bit in the cpumask except CPU offlining, - * in which case we should not be taking IPIs here. However check - * this just in case the logic is wrong somewhere, and don't underflow - * the active_cpus count. + * This IPI may be initiated from any source including those not + * running the mm, so there may be a racing IPI that comes after + * this one which finds the cpumask already clear. Check and avoid + * underflowing the active_cpus count in that case. The race should + * not otherwise be a problem, but the TLB must be flushed because + * that's what the caller expects. */ if (cpumask_test_cpu(cpu, mm_cpumask(mm))) { atomic_dec(&mm->context.active_cpus); cpumask_clear_cpu(cpu, mm_cpumask(mm)); - } else { - WARN_ON_ONCE(1); } out_flush: |