The new MMF_KERNEL flag identifies kernel-owned mm's. Checking the flag with mm_is_kernel() is preferred over comparing directly against &init_mm.
No functional change, as only init_mm has MMF_KERNEL set for now. Assisted-by: Codex:GPT-5.5 Signed-off-by: Kevin Brodsky <[email protected]> --- arch/x86/include/asm/tlbflush.h | 8 ++++---- arch/x86/mm/pgtable.c | 2 +- arch/x86/mm/tlb.c | 9 +++++---- 3 files changed, 10 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 0545fe75c3fa..4af1cf711a60 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -159,10 +159,10 @@ struct tlb_state_shared { * - Actively using an mm. Our CPU's bit will be set in * mm_cpumask(loaded_mm) and is_lazy == false; * - * - Not using a real mm. loaded_mm == &init_mm. Our CPU's bit - * will not be set in mm_cpumask(&init_mm) and is_lazy == false. + * - Not using a real mm. loaded_mm is a kernel mm. Our CPU's bit + * will not be set in mm_cpumask(loaded_mm) and is_lazy == false. * - * - Lazily using a real mm. loaded_mm != &init_mm, our bit + * - Lazily using a real mm. loaded_mm is not a kernel mm, our bit * is set in mm_cpumask(loaded_mm), but is_lazy == true. * We're heuristically guessing that the CR3 load we * skipped more than makes up for the overhead added by @@ -188,7 +188,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state_shared, cpu_tlbstate_shared); #define enter_lazy_tlb enter_lazy_tlb static __always_inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) { - if (this_cpu_read(cpu_tlbstate.loaded_mm) == &init_mm) + if (mm_is_kernel(this_cpu_read(cpu_tlbstate.loaded_mm))) return; this_cpu_write(cpu_tlbstate_shared.is_lazy, true); diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index f32facdb3035..91d2a6f2ac5a 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -168,7 +168,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count) bool failed = false; gfp_t gfp = GFP_PGTABLE_USER; - if (mm == &init_mm) + if (mm_is_kernel(mm)) gfp &= ~__GFP_ACCOUNT; gfp &= ~__GFP_HIGHMEM; diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 1023acadd8f8..5517cab8ad00 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -594,7 +594,7 @@ void leave_mm(void) * This needs to happen before any other sanity checks due to * intel_idle's shenanigans. */ - if (loaded_mm == &init_mm) + if (mm_is_kernel(loaded_mm)) return; /* Warn if we're not lazy. */ @@ -855,7 +855,7 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, * cpu_tlbstate_shared.is_lazy whether or not to send an IPI. */ if (IS_ENABLED(CONFIG_DEBUG_VM) && - WARN_ON_ONCE(prev != &init_mm && !is_notrack_mm(prev) && + WARN_ON_ONCE(!mm_is_kernel(prev) && !is_notrack_mm(prev) && !cpumask_test_cpu(cpu, mm_cpumask(next)))) cpumask_set_cpu(cpu, mm_cpumask(next)); @@ -932,7 +932,8 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, * This way switch_mm() must see the new tlb_gen or * flush_tlb_mm_range() must see the new loaded_mm, or both. */ - if (next != &init_mm && !cpumask_test_cpu(cpu, mm_cpumask(next))) + if (!mm_is_kernel(next) && + !cpumask_test_cpu(cpu, mm_cpumask(next))) cpumask_set_cpu(cpu, mm_cpumask(next)); else smp_mb(); @@ -1134,7 +1135,7 @@ static void flush_tlb_func(void *info) return; } - if (unlikely(loaded_mm == &init_mm)) + if (unlikely(mm_is_kernel(loaded_mm))) return; /* Reload the ASID if transitioning into or out of a global ASID */ -- 2.51.2
