On Tue, Apr 21, 2020 at 05:14:22PM -0700, Michel Lespinasse wrote:
> Rename the mmap_sem field to mmap_lock. Any new uses of this lock
Shouldn't some of these be folded into the previous patch?
(Quoted below are the ones I think should be mmap_assert_locked())
This does illustrate that we also need an mmap_assert_write_locked(),
and lockdep_assert_held_write() doesn't have a non-lockdep counterpart.
We can at least assert that it's not _unlocked_, even if we can't assert
that it's definitely _write_ locked.
> +++ b/arch/x86/events/core.c
> @@ -2179,10 +2179,10 @@ static void x86_pmu_event_mapped(struct perf_event *event, struct mm_struct *mm)
> * userspace with CR4.PCE clear while another task is still
> * doing on_each_cpu_mask() to propagate CR4.PCE.
> *
> - * For now, this can't happen because all callers hold mmap_sem
> + * For now, this can't happen because all callers hold mmap_lock
> * for write. If this changes, we'll need a different solution.
> */
> - lockdep_assert_held_write(&mm->mmap_sem);
> + lockdep_assert_held_write(&mm->mmap_lock);
>
> if (atomic_inc_return(&mm->context.perf_rdpmc_allowed) == 1)
> on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);
> diff --git a/mm/hmm.c b/mm/hmm.c
> index 280585833adf..8660aec6aafa 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -581,7 +581,7 @@ long hmm_range_fault(struct hmm_range *range)
> struct mm_struct *mm = range->notifier->mm;
> int ret;
>
> - lockdep_assert_held(&mm->mmap_sem);
> + lockdep_assert_held(&mm->mmap_lock);
>
> do {
> /* If range is no longer valid force retry. */
> diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
> index cfd0a03bf5cc..6717278d6d49 100644
> --- a/mm/mmu_notifier.c
> +++ b/mm/mmu_notifier.c
> @@ -609,7 +609,7 @@ int __mmu_notifier_register(struct mmu_notifier *subscription,
> struct mmu_notifier_subscriptions *subscriptions = NULL;
> int ret;
>
> - lockdep_assert_held_write(&mm->mmap_sem);
> + lockdep_assert_held_write(&mm->mmap_lock);
> BUG_ON(atomic_read(&mm->mm_users) <= 0);
>
> if (IS_ENABLED(CONFIG_LOCKDEP)) {
> @@ -761,7 +761,7 @@ struct mmu_notifier *mmu_notifier_get_locked(const struct mmu_notifier_ops *ops,
> struct mmu_notifier *subscription;
> int ret;
>
> - lockdep_assert_held_write(&mm->mmap_sem);
> + lockdep_assert_held_write(&mm->mmap_lock);
>
> if (mm->notifier_subscriptions) {
> subscription = find_get_mmu_notifier(mm, ops);
> @@ -1006,7 +1006,7 @@ int mmu_interval_notifier_insert_locked(
> mm->notifier_subscriptions;
> int ret;
>
> - lockdep_assert_held_write(&mm->mmap_sem);
> + lockdep_assert_held_write(&mm->mmap_lock);
>
> if (!subscriptions || !subscriptions->has_itree) {
> ret = __mmu_notifier_register(NULL, mm);
> diff --git a/mm/pagewalk.c b/mm/pagewalk.c
> index 928df1638c30..d669a3146c0f 100644
> --- a/mm/pagewalk.c
> +++ b/mm/pagewalk.c
> @@ -395,7 +396,7 @@ int walk_page_range(struct mm_struct *mm, unsigned long start,
> if (!walk.mm)
> return -EINVAL;
>
> - lockdep_assert_held(&walk.mm->mmap_sem);
> + lockdep_assert_held(&walk.mm->mmap_lock);
>
> vma = find_vma(walk.mm, start);
> do {
> @@ -453,7 +454,7 @@ int walk_page_range_novma(struct mm_struct *mm, unsigned long start,
> if (start >= end || !walk.mm)
> return -EINVAL;
>
> - lockdep_assert_held(&walk.mm->mmap_sem);
> + lockdep_assert_held(&walk.mm->mmap_lock);
>
> return __walk_page_range(start, end, &walk);
> }
> @@ -472,7 +473,7 @@ int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
> if (!walk.mm)
> return -EINVAL;
>
> - lockdep_assert_held(&walk.mm->mmap_sem);
> + lockdep_assert_held(&walk.mm->mmap_lock);
>
> err = walk_page_test(vma->vm_start, vma->vm_end, &walk);
> if (err > 0)
> diff --git a/mm/util.c b/mm/util.c
> index ea2e15b21446..56c562f7ad19 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -437,7 +437,7 @@ int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
> unsigned long locked_vm, limit;
> int ret = 0;
>
> - lockdep_assert_held_write(&mm->mmap_sem);
> + lockdep_assert_held_write(&mm->mmap_lock);
>
> locked_vm = mm->locked_vm;
> if (inc) {
> --
> 2.26.1.301.g55bc3eb7cb9-goog
>
