powerpc/book3s64/radix: Remove WARN_ON in destroy_context()

[linux-2.6-block.git] / arch / powerpc / mm / book3s64 / mmu_context.c

diff --git a/arch/powerpc/mm/book3s64/mmu_context.c b/arch/powerpc/mm/book3s64/mmu_context.c
index 2d0cb5ba9a47e89317a1ebc9a46c3ff7d1a1a423..0ba30b8b935bcf2a0251185b2655555542c053c0 100644 (file)
--- a/arch/powerpc/mm/book3s64/mmu_context.c
+++ b/arch/powerpc/mm/book3s64/mmu_context.c
@@ -256,8 +256,21 @@ void destroy_context(struct mm_struct *mm)
 #ifdef CONFIG_SPAPR_TCE_IOMMU
        WARN_ON_ONCE(!list_empty(&mm->context.iommu_group_mem_list));
 #endif
+       /*
+        * For tasks which were successfully initialized we end up calling
+        * arch_exit_mmap() which clears the process table entry. And
+        * arch_exit_mmap() is called before the required fullmm TLB flush
+        * which does a RIC=2 flush. Hence for an initialized task, we do clear
+        * any cached process table entries.
+        *
+        * The condition below handles the error case during task init. We have
+        * set the process table entry early and if we fail a task
+        * initialization, we need to ensure the process table entry is zeroed.
+        * We need not worry about process table entry caches because the task
+        * never ran with the PID value.
+        */
        if (radix_enabled())
-               WARN_ON(process_tb[mm->context.id].prtb0 != 0);
+               process_tb[mm->context.id].prtb0 = 0;
        else
                subpage_prot_free(mm);
        destroy_contexts(&mm->context);