From: Qi Zheng <zhengqi.arch@bytedance.com>
To: Andrew Morton <akpm@linux-foundation.org>
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: Fri, 24 Sep 2021 10:24:06 +0800 [thread overview]
Message-ID: <2eca94ce-4e26-aff6-240d-39baf1a9cc36@bytedance.com> (raw)
In-Reply-To: <20210923161738.990b61933c96df78bc1bf96d@linux-foundation.org>
On 9/24/21 7:17 AM, Andrew Morton wrote:
> 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?
Yes, and I see this neater version has merged into your mm tree,
thanks. :)
>
> +++ 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;
> }
> _
>
prev parent reply other threads:[~2021-09-24 2:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 12:26 [PATCH] mm/memory_failure: Fix the missing pte_unmap() call Qi Zheng
2021-09-23 15:19 ` David Hildenbrand
2021-09-23 15:30 ` Qi Zheng
2021-09-23 23:17 ` Andrew Morton
2021-09-24 0:31 ` Naoya Horiguchi
2021-09-24 2:24 ` Qi Zheng [this message]
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