linux-kernel - [PATCH AUTOSEL 4.19 37/55] MIPS: add PMD table accounting into MIPS'pmd_alloc

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Message-Id: <20210706112638.2065023-37-sashal@kernel.org>
Date:   Tue,  6 Jul 2021 07:26:20 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Huang Pei <huangpei@...ngson.cn>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Sasha Levin <sashal@...nel.org>, linux-mips@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 37/55] MIPS: add PMD table accounting into MIPS'pmd_alloc_one

From: Huang Pei <huangpei@...ngson.cn>

[ Upstream commit ed914d48b6a1040d1039d371b56273d422c0081e ]

This fixes Page Table accounting bug.

MIPS is the ONLY arch just defining __HAVE_ARCH_PMD_ALLOC_ONE alone.
Since commit b2b29d6d011944 (mm: account PMD tables like PTE tables),
"pmd_free" in asm-generic with PMD table accounting and "pmd_alloc_one"
in MIPS without PMD table accounting causes PageTable accounting number
negative, which read by global_zone_page_state(), always returns 0.

Signed-off-by: Huang Pei <huangpei@...ngson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/mips/include/asm/pgalloc.h | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h
index 39b9f311c4ef..f800872f867b 100644
--- a/arch/mips/include/asm/pgalloc.h
+++ b/arch/mips/include/asm/pgalloc.h
@@ -93,11 +93,15 @@ do {							\
 
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 {
-	pmd_t *pmd;
+	pmd_t *pmd = NULL;
+	struct page *pg;
 
-	pmd = (pmd_t *) __get_free_pages(GFP_KERNEL, PMD_ORDER);
-	if (pmd)
+	pg = alloc_pages(GFP_KERNEL | __GFP_ACCOUNT, PMD_ORDER);
+	if (pg) {
+		pgtable_pmd_page_ctor(pg);
+		pmd = (pmd_t *)page_address(pg);
 		pmd_init((unsigned long)pmd, (unsigned long)invalid_pte_table);
+	}
 	return pmd;
 }
 
-- 
2.30.2