From: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Date: Wed, 25 Jan 2023 17:05:31 +0000 (-0800)
Subject: mm/hugetlb: convert hugetlbfs_pagecache_present() to folios
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d7618ad8f7ff2771a192adc4e7da08af00d269ae;p=users%2Fjedix%2Flinux-maple.git

mm/hugetlb: convert hugetlbfs_pagecache_present() to folios

Refactor hugetlbfs_pagecache_present() to avoid getting and dropping a
refcount on a page.  Use RCU and page_cache_next_miss() instead.

Link: https://lkml.kernel.org/r/20230125170537.96973-3-sidhartha.kumar@oracle.com
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b246f2b4d0bd..a0d486ed5411 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5651,17 +5651,15 @@ out_release_old:
 static bool hugetlbfs_pagecache_present(struct hstate *h,
 			struct vm_area_struct *vma, unsigned long address)
 {
-	struct address_space *mapping;
-	pgoff_t idx;
-	struct page *page;
+	struct address_space *mapping = vma->vm_file->f_mapping;
+	pgoff_t idx = vma_hugecache_offset(h, vma, address);
+	bool present;
 
-	mapping = vma->vm_file->f_mapping;
-	idx = vma_hugecache_offset(h, vma, address);
+	rcu_read_lock();
+	present = page_cache_next_miss(mapping, idx, 1) != idx;
+	rcu_read_unlock();
 
-	page = find_get_page(mapping, idx);
-	if (page)
-		put_page(page);
-	return page != NULL;
+	return present;
 }
 
 int hugetlb_add_to_page_cache(struct page *page, struct address_space *mapping,