From: Miaohe Lin <linmiaohe@huawei.com>
To: <akpm@linux-foundation.org>
Cc: <ying.huang@intel.com>, <dennis@kernel.org>,
<tim.c.chen@linux.intel.com>, <hughd@google.com>,
<hannes@cmpxchg.org>, <mhocko@suse.com>, <iamjoonsoo.kim@lge.com>,
<alexs@kernel.org>, <david@redhat.com>, <minchan@kernel.org>,
<richard.weiyang@gmail.com>, <linux-kernel@vger.kernel.org>,
<linux-mm@kvack.org>, <linmiaohe@huawei.com>
Subject: [PATCH v2 4/5] mm/swap: remove confusing checking for non_swap_entry() in swap_ra_info()
Date: Sat, 17 Apr 2021 05:40:38 -0400 [thread overview]
Message-ID: <20210417094039.51711-5-linmiaohe@huawei.com> (raw)
In-Reply-To: <20210417094039.51711-1-linmiaohe@huawei.com>
While we released the pte lock, somebody else might faulted in this pte.
So we should check whether it's swap pte first to guard against such race
or swp_type would be unexpected. But the swap_entry isn't used in this
function and we will have enough checking when we really operate the PTE
entries later. So checking for non_swap_entry() is not really needed here
and should be removed to avoid confusion.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
mm/swap_state.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 272ea2108c9d..df5405384520 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -721,7 +721,6 @@ static void swap_ra_info(struct vm_fault *vmf,
{
struct vm_area_struct *vma = vmf->vma;
unsigned long ra_val;
- swp_entry_t entry;
unsigned long faddr, pfn, fpfn;
unsigned long start, end;
pte_t *pte, *orig_pte;
@@ -739,11 +738,6 @@ static void swap_ra_info(struct vm_fault *vmf,
faddr = vmf->address;
orig_pte = pte = pte_offset_map(vmf->pmd, faddr);
- entry = pte_to_swp_entry(*pte);
- if ((unlikely(non_swap_entry(entry)))) {
- pte_unmap(orig_pte);
- return;
- }
fpfn = PFN_DOWN(faddr);
ra_val = GET_SWAP_RA_VAL(vma);
--
2.19.1
next prev parent reply other threads:[~2021-04-17 9:42 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-17 9:40 [PATCH v2 0/5] close various race windows for swap Miaohe Lin
2021-04-17 9:40 ` [PATCH v2 1/5] mm/swapfile: add percpu_ref support " Miaohe Lin
2021-04-19 2:48 ` Huang, Ying
2021-04-19 6:46 ` Miaohe Lin
2021-04-19 7:09 ` Huang, Ying
2021-04-19 7:35 ` Miaohe Lin
2021-04-19 7:52 ` Huang, Ying
2021-04-19 8:20 ` Miaohe Lin
2021-04-17 9:40 ` [PATCH v2 2/5] mm/swapfile: use percpu_ref to serialize against concurrent swapoff Miaohe Lin
2021-04-19 2:54 ` Huang, Ying
2021-04-19 6:57 ` Miaohe Lin
2021-04-17 9:40 ` [PATCH v2 3/5] swap: fix do_swap_page() race with swapoff Miaohe Lin
2021-04-19 2:23 ` Huang, Ying
2021-04-19 6:54 ` Miaohe Lin
2021-04-17 9:40 ` Miaohe Lin [this message]
2021-04-19 1:53 ` [PATCH v2 4/5] mm/swap: remove confusing checking for non_swap_entry() in swap_ra_info() Huang, Ying
2021-04-19 6:46 ` Miaohe Lin
2021-04-17 9:40 ` [PATCH v2 5/5] mm/shmem: fix shmem_swapin() race with swapoff Miaohe Lin
2021-04-19 2:15 ` Huang, Ying
2021-04-19 6:49 ` Miaohe Lin
2021-04-19 7:04 ` Huang, Ying
2021-04-19 7:14 ` Miaohe Lin
2021-04-19 7:41 ` Huang, Ying
2021-04-19 8:18 ` Miaohe Lin
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