+ mm-damon-introduce-damon_get_folio.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/damon: introduce damon_get_folio()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-damon-introduce-damon_get_folio.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-introduce-damon_get_folio.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: mm/damon: introduce damon_get_folio()
Date: Fri, 30 Dec 2022 15:08:44 +0800

Introduce damon_get_folio(), and the temporary wrapper function
damon_get_page(), which help us to convert damon related functions to use
folios, and it will be dropped once the conversion is completed.

Link: https://lkml.kernel.org/r/20221230070849.63358-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/mm/damon/ops-common.c~mm-damon-introduce-damon_get_folio
+++ a/mm/damon/ops-common.c
@@ -16,21 +16,25 @@
  * Get an online page for a pfn if it's in the LRU list.  Otherwise, returns
  * NULL.
  *
- * The body of this function is stolen from the 'page_idle_get_page()'.  We
+ * The body of this function is stolen from the 'page_idle_get_folio()'.  We
  * steal rather than reuse it because the code is quite simple.
  */
-struct page *damon_get_page(unsigned long pfn)
+struct folio *damon_get_folio(unsigned long pfn)
 {
 	struct page *page = pfn_to_online_page(pfn);
+	struct folio *folio;
 
-	if (!page || !PageLRU(page) || !get_page_unless_zero(page))
+	if (!page || PageTail(page))
 		return NULL;
 
-	if (unlikely(!PageLRU(page))) {
-		put_page(page);
-		page = NULL;
+	folio = page_folio(page);
+	if (!folio_test_lru(folio) || !folio_try_get(folio))
+		return NULL;
+	if (unlikely(page_folio(page) != folio || !folio_test_lru(folio))) {
+		folio_put(folio);
+		folio = NULL;
 	}
-	return page;
+	return folio;
 }
 
 void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr)
--- a/mm/damon/ops-common.h~mm-damon-introduce-damon_get_folio
+++ a/mm/damon/ops-common.h
@@ -7,7 +7,14 @@
 
 #include <linux/damon.h>
 
-struct page *damon_get_page(unsigned long pfn);
+struct folio *damon_get_folio(unsigned long pfn);
+static inline struct page *damon_get_page(unsigned long pfn)
+{
+	struct folio *folio = damon_get_folio(pfn);
+
+	/* when folio is NULL, return &(0->page) mean return NULL */
+	return &folio->page;
+}
 
 void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr);
 void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr);
_

Patches currently in -mm which might be from wangkefeng.wang@huawei.com are

mm-hwposion-support-recovery-from-ksm_might_need_to_copy.patch
mm-hwposion-support-recovery-from-ksm_might_need_to_copy-v3.patch
mm-huge_memory-convert-madvise_free_huge_pmd-to-use-a-folio.patch
mm-swap-convert-mark_page_lazyfree-to-folio_mark_lazyfree.patch
mm-huge_memory-convert-split_huge_pages_all-to-use-a-folio.patch
mm-page_idle-convert-page-idle-to-use-a-folio.patch
mm-damon-introduce-damon_get_folio.patch
mm-damon-convert-damon_ptep-pmdp_mkold-to-use-a-folio.patch
mm-damon-paddr-convert-damon_pa_-to-use-a-folio.patch
mm-damon-vaddr-convert-damon_young_pmd_entry-to-use-a-folio.patch
mm-damon-remove-unneeded-damon_get_page.patch
mm-damon-vaddr-convert-hugetlb-related-functions-to-use-a-folio.patch