Re: [PATCH] mm: Convert DAX lock/unlock page to lock/unlock folio

[Jane Chu]

On 8/22/2023 4:13 PM, Matthew Wilcox (Oracle) wrote:
[..]

diff --git a/mm/memory-failure.c b/mm/memory-failure.c

index a6c3af985554..b81d6eb4e6ff 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1717,16 +1717,11 @@ static int mf_generic_kill_procs(unsigned long long 
pfn, int flags,
                struct dev_pagemap *pgmap)
  {
        struct page *page = pfn_to_page(pfn);

Looks like the above line, that is, the 'page' pointer is no longer needed.

+       struct folio *folio = page_folio(page);
        LIST_HEAD(to_kill);
        dax_entry_t cookie;
        int rc = 0;

- /*

-        * Pages instantiated by device-dax (not filesystem-dax)
-        * may be compound pages.
-        */
-       page = compound_head(page);
-
        /*
         * Prevent the inode from being freed while we are interrogating
         * the address_space, typically this would be handled by
@@ -1734,11 +1729,11 @@ static int mf_generic_kill_procs(unsigned long long 
pfn, int flags,
         * also prevents changes to the mapping of this pfn until
         * poison signaling is complete.
         */
-       cookie = dax_lock_page(page);
+       cookie = dax_lock_folio(folio);
        if (!cookie)
                return -EBUSY;

- if (hwpoison_filter(page)) {

+       if (hwpoison_filter(&folio->page)) {
                rc = -EOPNOTSUPP;
                goto unlock;
        }
@@ -1760,7 +1755,7 @@ static int mf_generic_kill_procs(unsigned long long pfn, 
int flags,
         * Use this flag as an indication that the dax page has been
         * remapped UC to prevent speculative consumption of poison.
         */
-       SetPageHWPoison(page);
+       SetPageHWPoison(&folio->page);

/*

         * Unlike System-RAM there is no possibility to swap in a
@@ -1769,11 +1764,11 @@ static int mf_generic_kill_procs(unsigned long long 
pfn, int flags,
         * SIGBUS (i.e. MF_MUST_KILL)
         */
        flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
-       collect_procs(page, &to_kill, true);
+       collect_procs(&folio->page, &to_kill, true);

- unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags);

+       unmap_and_kill(&to_kill, pfn, folio->mapping, folio->index, flags);
  unlock:
-       dax_unlock_page(page, cookie);
+       dax_unlock_folio(folio, cookie);
        return rc;
  }

thanks,
-jane