On Mon, Oct 25, 2021 at 4:06 PM Naoya Horiguchi
<naoya.horiguchi@xxxxxxxxx> wrote:
>
> From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
>
> Now memory_failure() and unpoison_memory() are protected by mf_mutex,
> so no need to explicitly check races between them. So remove them.
It seems this patch could be folded into patch #1. Some "unlock_mutex"
were added by patch #1 then they were removed by this patch
immediately, it seems a bit of a waste and this patch is actually the
by-product of patch #1.
>
> Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
> ---
> mm/memory-failure.c | 37 -------------------------------------
> 1 file changed, 37 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 97297edfbd8e..a47b741ca04b 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1507,14 +1507,6 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags)
> lock_page(head);
> page_flags = head->flags;
>
> - if (!PageHWPoison(head)) {
> - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn);
> - num_poisoned_pages_dec();
> - unlock_page(head);
> - put_page(head);
> - return 0;
> - }
> -
> /*
> * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so
> * simply disable it. In order to make it work properly, we need
> @@ -1789,16 +1781,6 @@ int memory_failure(unsigned long pfn, int flags)
> */
> page_flags = p->flags;
>
> - /*
> - * unpoison always clear PG_hwpoison inside page lock
> - */
> - if (!PageHWPoison(p)) {
> - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn);
> - num_poisoned_pages_dec();
> - unlock_page(p);
> - put_page(p);
> - goto unlock_mutex;
> - }
> if (hwpoison_filter(p)) {
> if (TestClearPageHWPoison(p))
> num_poisoned_pages_dec();
> @@ -2016,17 +1998,6 @@ int unpoison_memory(unsigned long pfn)
> goto unlock_mutex;
> }
>
> - /*
> - * unpoison_memory() can encounter thp only when the thp is being
> - * worked by memory_failure() and the page lock is not held yet.
> - * In such case, we yield to memory_failure() and make unpoison fail.
> - */
> - if (!PageHuge(page) && PageTransHuge(page)) {
> - unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n",
> - pfn, &unpoison_rs);
> - goto unlock_mutex;
> - }
> -
> if (!get_hwpoison_page(p, flags)) {
> if (TestClearPageHWPoison(p))
> num_poisoned_pages_dec();
> @@ -2035,20 +2006,12 @@ int unpoison_memory(unsigned long pfn)
> goto unlock_mutex;
> }
>
> - lock_page(page);
> - /*
> - * This test is racy because PG_hwpoison is set outside of page lock.
> - * That's acceptable because that won't trigger kernel panic. Instead,
> - * the PG_hwpoison page will be caught and isolated on the entrance to
> - * the free buddy page pool.
> - */
> if (TestClearPageHWPoison(page)) {
> unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",
> pfn, &unpoison_rs);
> num_poisoned_pages_dec();
> freeit = 1;
> }
> - unlock_page(page);
>
> put_page(page);
> if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1))
> --
> 2.25.1
>
