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SubjectRe: [PATCH -fixes 2/2] riscv: Fix set_huge_pte_at() for NAPOT mappings when a swap entry is set
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Hi Conor,

On 30/09/2023 11:14, Conor Dooley wrote:
> On Thu, Sep 28, 2023 at 05:18:46PM +0200, Alexandre Ghiti wrote:
>> We used to determine the number of page table entries to set for a NAPOT
>> hugepage by using the pte value which actually fails when the pte to set is
>> a swap entry.
>>
>> So take advantage of a recent fix for arm64 reported in [1] which
>> introduces the size of the mapping as an argument of set_huge_pte_at(): we
>> can then use this size to compute the number of page table entries to set
>> for a NAPOT region.
>>
>> Fixes: 82a1a1f3bfb6 ("riscv: mm: support Svnapot in hugetlb page")
>> Reported-by: Ryan Roberts <ryan.roberts@arm.com>
>> Closes: https://lore.kernel.org/linux-arm-kernel/20230922115804.2043771-1-ryan.roberts@arm.com/ [1]
>> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> Breaks the build. Your $subject marks this for -fixes, but this will not
> build there, as it relies on content that's not yet in that branch.
> AFAICT, you're going to have to resend this with akpm on CC, as the
> dependency is in his tree...


I see, but I still don't understand why -fixes does not point to the
latest rcX instead of staying on rc1? The patch which this series
depends on just made it to rc4.

Thanks,

Alex


> Thanks,
> Conor.
>
>> ---
>> arch/riscv/mm/hugetlbpage.c | 19 +++++++++++++------
>> 1 file changed, 13 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
>> index e4a2ace92dbe..b52f0210481f 100644
>> --- a/arch/riscv/mm/hugetlbpage.c
>> +++ b/arch/riscv/mm/hugetlbpage.c
>> @@ -183,15 +183,22 @@ void set_huge_pte_at(struct mm_struct *mm,
>> pte_t pte,
>> unsigned long sz)
>> {
>> + unsigned long hugepage_shift;
>> int i, pte_num;
>>
>> - if (!pte_napot(pte)) {
>> - set_pte_at(mm, addr, ptep, pte);
>> - return;
>> - }
>> + if (sz >= PGDIR_SIZE)
>> + hugepage_shift = PGDIR_SHIFT;
>> + else if (sz >= P4D_SIZE)
>> + hugepage_shift = P4D_SHIFT;
>> + else if (sz >= PUD_SIZE)
>> + hugepage_shift = PUD_SHIFT;
>> + else if (sz >= PMD_SIZE)
>> + hugepage_shift = PMD_SHIFT;
>> + else
>> + hugepage_shift = PAGE_SHIFT;
>>
>> - pte_num = napot_pte_num(napot_cont_order(pte));
>> - for (i = 0; i < pte_num; i++, ptep++, addr += PAGE_SIZE)
>> + pte_num = sz >> hugepage_shift;
>> + for (i = 0; i < pte_num; i++, ptep++, addr += (1 << hugepage_shift))
>> set_pte_at(mm, addr, ptep, pte);
>> }
>>
>> --
>> 2.39.2
>>
>>
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>> linux-riscv@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>>
>> _______________________________________________
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>> http://lists.infradead.org/mailman/listinfo/linux-riscv

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