From: Yu Zhao <yuzhao@google.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Yu Zhao <yuzhao@google.com>
Subject: [PATCH] mm: fix swap offset when replacing shmem page
Date: Sun, 18 Nov 2018 17:47:19 -0700 [thread overview]
Message-ID: <20181119004719.156411-1-yuzhao@google.com> (raw)
We used to have a single swap address space with swp_entry_t.val
as its radix tree index. This is not the case anymore. Now Each
swp_type() has its own address space and should use swp_offset()
as radix tree index.
Signed-off-by: Yu Zhao <yuzhao@google.com>
---
mm/shmem.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index d44991ea5ed4..a92c6ae26915 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1509,11 +1509,13 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
{
struct page *oldpage, *newpage;
struct address_space *swap_mapping;
- pgoff_t swap_index;
+ swp_entry_t entry;
int error;
+ VM_BUG_ON(PageSwapCache(*pagep));
+
oldpage = *pagep;
- swap_index = page_private(oldpage);
+ entry.val = page_private(oldpage);
swap_mapping = page_mapping(oldpage);
/*
@@ -1532,7 +1534,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
__SetPageLocked(newpage);
__SetPageSwapBacked(newpage);
SetPageUptodate(newpage);
- set_page_private(newpage, swap_index);
+ set_page_private(newpage, entry.val);
SetPageSwapCache(newpage);
/*
@@ -1540,7 +1542,8 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
* a nice clean interface for us to replace oldpage by newpage there.
*/
xa_lock_irq(&swap_mapping->i_pages);
- error = shmem_replace_entry(swap_mapping, swap_index, oldpage, newpage);
+ error = shmem_replace_entry(swap_mapping, swp_offset(entry),
+ oldpage, newpage);
if (!error) {
__inc_node_page_state(newpage, NR_FILE_PAGES);
__dec_node_page_state(oldpage, NR_FILE_PAGES);
--
2.19.1.1215.g8438c0b245-goog
next reply other threads:[~2018-11-19 0:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 0:47 Yu Zhao [this message]
2018-11-19 1:09 ` [PATCH v2] mm: fix swap offset when replacing shmem page Yu Zhao
2018-11-19 22:11 ` Hugh Dickins
2018-11-20 1:29 ` Yu Zhao
2018-11-20 5:07 ` Hugh Dickins
2018-11-20 13:12 ` Matthew Wilcox
2018-11-21 21:54 ` [PATCH v3] mm: use swp_offset as key in shmem_replace_page() Yu Zhao
2018-11-21 22:11 ` Matthew Wilcox
2018-11-22 0:36 ` Hugh Dickins
2018-11-22 5:01 ` Andrew Morton
2018-11-23 20:11 ` Hugh Dickins
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