With mm_cpumask, there is less reason to keep the mm_users special case
in the TLB flushing code, because IPIs will be filtered out by the mask.
These special cases are another complicated set of races e.g., vs
kthread_use_mm that make this code tricky to reason about.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/alpha/kernel/smp.c | 68 +++++++++--------------------------------
1 file changed, 15 insertions(+), 53 deletions(-)
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index b702372fbaba..e436c056267d 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -639,23 +639,6 @@ ipi_flush_tlb_mm(void *x)
void
flush_tlb_mm(struct mm_struct *mm)
{
- preempt_disable();
-
- if (mm == current->active_mm) {
- flush_tlb_current(mm);
- if (atomic_read(&mm->mm_users) <= 1) {
- int cpu, this_cpu = smp_processor_id();
- for (cpu = 0; cpu < NR_CPUS; cpu++) {
- if (!cpu_online(cpu) || cpu == this_cpu)
- continue;
- if (mm->context[cpu])
- mm->context[cpu] = 0;
- }
- preempt_enable();
- return;
- }
- }
-
/*
* TLB flush IPIs will be sent to all CPUs with mm_cpumask set. The
* problem of ordering the load of mm_cpumask vs a CPU switching to
@@ -666,8 +649,12 @@ flush_tlb_mm(struct mm_struct *mm)
* The other side is switch_mm.
*/
smp_mb();
+ preempt_disable();
+ if (mm == current->active_mm)
+ flush_tlb_current(mm);
+ else
+ flush_tlb_other(mm);
smp_call_function_many(mm_cpumask(mm), ipi_flush_tlb_mm, mm, 1);
-
preempt_enable();
}
EXPORT_SYMBOL(flush_tlb_mm);
@@ -696,30 +683,17 @@ flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
struct flush_tlb_page_struct data;
struct mm_struct *mm = vma->vm_mm;
- preempt_disable();
-
- if (mm == current->active_mm) {
- flush_tlb_current_page(mm, vma, addr);
- if (atomic_read(&mm->mm_users) <= 1) {
- int cpu, this_cpu = smp_processor_id();
- for (cpu = 0; cpu < NR_CPUS; cpu++) {
- if (!cpu_online(cpu) || cpu == this_cpu)
- continue;
- if (mm->context[cpu])
- mm->context[cpu] = 0;
- }
- preempt_enable();
- return;
- }
- }
-
data.vma = vma;
data.mm = mm;
data.addr = addr;
smp_mb(); /* see flush_tlb_mm */
+ preempt_disable();
+ if (mm == current->active_mm)
+ flush_tlb_current_page(mm, vma, addr);
+ else
+ flush_tlb_other(mm);
smp_call_function_many(mm_cpumask(mm), ipi_flush_tlb_page, &data, 1);
-
preempt_enable();
}
EXPORT_SYMBOL(flush_tlb_page);
@@ -751,24 +725,12 @@ flush_icache_user_page(struct vm_area_struct *vma, struct page *page,
if ((vma->vm_flags & VM_EXEC) == 0)
return;
+ smp_mb(); /* see flush_tlb_mm */
preempt_disable();
-
- if (mm == current->active_mm) {
+ if (mm == current->active_mm)
__load_new_mm_context(mm);
- if (atomic_read(&mm->mm_users) <= 1) {
- int cpu, this_cpu = smp_processor_id();
- for (cpu = 0; cpu < NR_CPUS; cpu++) {
- if (!cpu_online(cpu) || cpu == this_cpu)
- continue;
- if (mm->context[cpu])
- mm->context[cpu] = 0;
- }
- preempt_enable();
- return;
- }
- }
-
- smp_call_function(ipi_flush_icache_page, mm, 1);
-
+ else
+ flush_tlb_other(mm);
+ smp_call_function_many(mm_cpumask(mm), ipi_flush_icache_page, mm, 1);
preempt_enable();
}
--
2.40.1
