Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code

From: Ingo Molnar
Date: Sun Jun 14 2015 - 04:26:25 EST



* Ingo Molnar <mingo@xxxxxxxxxx> wrote:

> @@ -967,19 +979,32 @@ static void xen_pgd_unpin(struct mm_struct *mm)
> */
> void xen_mm_unpin_all(void)
> {
> - struct page *page;
> + struct task_struct *g, *p;
>
> - spin_lock(&pgd_lock);
> + spin_lock(&pgd_lock); /* Implies rcu_read_lock() for the task list iteration: */
>
> - list_for_each_entry(page, &pgd_list, lru) {
> - if (PageSavePinned(page)) {
> - BUG_ON(!PagePinned(page));
> - __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
> - ClearPageSavePinned(page);
> + for_each_process_thread(g, p) {
> + struct mm_struct *mm;
> + struct page *page;
> + pgd_t *pgd;
> +
> + task_lock(p);
> + mm = p->mm;
> + if (mm) {
> + pgd = mm->pgd;
> + page = virt_to_page(pgd);
> +
> + if (PageSavePinned(page)) {
> + BUG_ON(!PagePinned(page));
> + __xen_pgd_unpin(&init_mm, pgd);
> + ClearPageSavePinned(page);
> + }
> }
> + task_unlock(p);
> }
>
> spin_unlock(&pgd_lock);
> + rcu_read_unlock();
> }

I also removed the leftover stray rcu_read_unlock() from -v3.

Thanks,

Ingo
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