linux-kernel - [PATCH] LoongArch: mm: avoid unnecessary page fault retires on shared memory types

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Message-Id: <20220815040554.1455722-1-chenhuacai@loongson.cn>
Date:   Mon, 15 Aug 2022 12:05:54 +0800
From:   Huacai Chen <chenhuacai@...ngson.cn>
To:     Huacai Chen <chenhuacai@...nel.org>
Cc:     loongarch@...ts.linux.dev, Xuefeng Li <lixuefeng@...ngson.cn>,
        Guo Ren <guoren@...nel.org>, Xuerui Wang <kernel@...0n.name>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        linux-kernel@...r.kernel.org, Huacai Chen <chenhuacai@...ngson.cn>
Subject: [PATCH] LoongArch: mm: avoid unnecessary page fault retires on shared memory types

Commit d92725256b4f22d0 ("mm: avoid unnecessary page fault retires on
shared memory types") modifies do_page_fault() to handle the VM_FAULT_
COMPLETED case, but forget to change for LoongArch, so fix it as other
architectures does.

Fixes: d92725256b4f22d0 ("mm: avoid unnecessary page fault retires on shared memory types")
Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
---
 arch/loongarch/mm/fault.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/loongarch/mm/fault.c b/arch/loongarch/mm/fault.c
index 605579b19a00..1ccd53655cab 100644
--- a/arch/loongarch/mm/fault.c
+++ b/arch/loongarch/mm/fault.c
@@ -216,6 +216,10 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
 		return;
 	}
 
+	/* The fault is fully completed (including releasing mmap lock) */
+	if (fault & VM_FAULT_COMPLETED)
+		return;
+
 	if (unlikely(fault & VM_FAULT_RETRY)) {
 		flags |= FAULT_FLAG_TRIED;
 
-- 
2.31.1