[PATCH v2 4/5] mm/swap: remove confusing checking for non_swap_entry() in swap_ra_info()

From: Miaohe Lin
Date: Sat Apr 17 2021 - 05:42:01 EST


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@xxxxxxxxxx>
---
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