From: Andrew Morton <akpm@linux-foundation.org>
To: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: naoya.horiguchi@nec.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, songmuchun@bytedance.com
Subject: Re: [PATCH] mm/memory_failure: Fix the missing pte_unmap() call
Date: Thu, 23 Sep 2021 16:17:38 -0700 [thread overview]
Message-ID: <20210923161738.990b61933c96df78bc1bf96d@linux-foundation.org> (raw)
In-Reply-To: <20210923122642.4999-1-zhengqi.arch@bytedance.com>
On Thu, 23 Sep 2021 20:26:42 +0800 Qi Zheng <zhengqi.arch@bytedance.com> wrote:
> The paired pte_unmap() call is missing before the
> dev_pagemap_mapping_shift() returns. So fix it.
>
> ...
>
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -306,6 +306,7 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
> struct vm_area_struct *vma)
> {
> unsigned long address = vma_address(page, vma);
> + unsigned long ret = 0;
> pgd_t *pgd;
> p4d_t *p4d;
> pud_t *pud;
> @@ -330,10 +331,12 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
> return PMD_SHIFT;
> pte = pte_offset_map(pmd, address);
> if (!pte_present(*pte))
> - return 0;
> + goto unmap;
> if (pte_devmap(*pte))
> - return PAGE_SHIFT;
> - return 0;
> + ret = PAGE_SHIFT;
> +unmap:
> + pte_unmap(pte);
> + return ret;
> }
>
This is neater?
+++ a/mm/memory-failure.c
@@ -330,11 +330,8 @@ static unsigned long dev_pagemap_mapping
if (pmd_devmap(*pmd))
return PMD_SHIFT;
pte = pte_offset_map(pmd, address);
- if (!pte_present(*pte))
- goto unmap;
- if (pte_devmap(*pte))
+ if (pte_present(*pte) && pte_devmap(*pte))
ret = PAGE_SHIFT;
-unmap:
pte_unmap(pte);
return ret;
}
_
next prev parent reply other threads:[~2021-09-23 23:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 12:26 Qi Zheng
2021-09-23 15:19 ` David Hildenbrand
2021-09-23 15:30 ` Qi Zheng
2021-09-23 23:17 ` Andrew Morton [this message]
2021-09-24 0:31 ` Naoya Horiguchi
2021-09-24 2:24 ` Qi Zheng
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