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SubjectRe: [PATCH RESEND v5 5/5] iova: Add iova_len argument to iova_domain_init_rcaches()
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On 07/04/2022 09:27, Leizhen (ThunderTown) wrote:
>

Thanks for having a look....

>
> On 2022/4/4 19:27, John Garry wrote:
>> Add max opt argument to iova_domain_init_rcaches(), and use it to set the
>> rcaches range.
>>
>> Also fix up all users to set this value (at 0, meaning use default),
>> including a wrapper for that, iova_domain_init_rcaches_default().
>>
>> For dma-iommu.c we derive the iova_len argument from the IOMMU group
>> max opt DMA size.
>>
>> Signed-off-by: John Garry <john.garry@huawei.com>
>> ---
>> drivers/iommu/dma-iommu.c | 15 ++++++++++++++-
>> drivers/iommu/iova.c | 19 ++++++++++++++++---
>> drivers/vdpa/vdpa_user/iova_domain.c | 4 ++--
>> include/linux/iova.h | 3 ++-
>> 4 files changed, 34 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>> index 42ca42ff1b5d..19f35624611c 100644
>> --- a/drivers/iommu/dma-iommu.c
>> +++ b/drivers/iommu/dma-iommu.c
>> @@ -525,6 +525,8 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
>> struct iommu_dma_cookie *cookie = domain->iova_cookie;
>> unsigned long order, base_pfn;
>> struct iova_domain *iovad;
>> + size_t max_opt_dma_size;
>> + unsigned long iova_len = 0;
>> int ret;
>>
>> if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)
>> @@ -560,7 +562,18 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
>> }
>>
>> init_iova_domain(iovad, 1UL << order, base_pfn);
>> - ret = iova_domain_init_rcaches(iovad);
>> +
>> + max_opt_dma_size = iommu_group_get_max_opt_dma_size(dev->iommu_group);
>> + if (max_opt_dma_size) {
>> + unsigned long shift = __ffs(1UL << order);
>> +
>> + iova_len = roundup_pow_of_two(max_opt_dma_size);
>> + iova_len >>= shift;
>> + if (!iova_len)
>> + iova_len = 1;
>
> How about move "iovad->rcache_max_size = iova_len_to_rcache_max(iova_len);" here? So that,
> iova_domain_init_rcaches() can remain the same. And iova_domain_init_rcaches_default() does
> not need to be added.
>

I see your idea. I will say that I would rather not add
iova_domain_init_rcaches_default(). But personally I think it's better
to setup all rcache stuff only once and inside
iova_domain_init_rcaches(), as it is today.

In addition, it doesn't look reasonable to expose iova_len_to_rcache_max().

But maybe it's ok. Other opinion would be welcome...

Thanks,
John

>> + }
>> +
>> + ret = iova_domain_init_rcaches(iovad, iova_len);
>> if (ret)
>> return ret;
>>
>> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
>> index 5c22b9187b79..d65e79e132ee 100644
>> --- a/drivers/iommu/iova.c
>> +++ b/drivers/iommu/iova.c
>> @@ -706,12 +706,20 @@ static void iova_magazine_push(struct iova_magazine *mag, unsigned long pfn)
>> mag->pfns[mag->size++] = pfn;
>> }
>>
>> -int iova_domain_init_rcaches(struct iova_domain *iovad)
>> +static unsigned long iova_len_to_rcache_max(unsigned long iova_len)
>> +{
>> + return order_base_2(iova_len) + 1;
>> +}
>> +
>> +int iova_domain_init_rcaches(struct iova_domain *iovad, unsigned long iova_len)
>> {
>> unsigned int cpu;
>> int i, ret;
>>
>> - iovad->rcache_max_size = 6; /* Arbitrarily high default */
>> + if (iova_len)
>> + iovad->rcache_max_size = iova_len_to_rcache_max(iova_len);
>> + else
>> + iovad->rcache_max_size = 6; /* Arbitrarily high default */
>>
>> iovad->rcaches = kcalloc(iovad->rcache_max_size,
>> sizeof(struct iova_rcache),
>> @@ -755,7 +763,12 @@ int iova_domain_init_rcaches(struct iova_domain *iovad)
>> free_iova_rcaches(iovad);
>> return ret;
>> }
>> -EXPORT_SYMBOL_GPL(iova_domain_init_rcaches);
>> +
>> +int iova_domain_init_rcaches_default(struct iova_domain *iovad)
>> +{
>> + return iova_domain_init_rcaches(iovad, 0);
>> +}
>> +EXPORT_SYMBOL_GPL(iova_domain_init_rcaches_default);
>>
>> /*
>> * Try inserting IOVA range starting with 'iova_pfn' into 'rcache', and
>> diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
>> index 6daa3978d290..3a2acef98a4a 100644
>> --- a/drivers/vdpa/vdpa_user/iova_domain.c
>> +++ b/drivers/vdpa/vdpa_user/iova_domain.c
>> @@ -514,12 +514,12 @@ vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
>> spin_lock_init(&domain->iotlb_lock);
>> init_iova_domain(&domain->stream_iovad,
>> PAGE_SIZE, IOVA_START_PFN);
>> - ret = iova_domain_init_rcaches(&domain->stream_iovad);
>> + ret = iova_domain_init_rcaches_default(&domain->stream_iovad);
>> if (ret)
>> goto err_iovad_stream;
>> init_iova_domain(&domain->consistent_iovad,
>> PAGE_SIZE, bounce_pfns);
>> - ret = iova_domain_init_rcaches(&domain->consistent_iovad);
>> + ret = iova_domain_init_rcaches_default(&domain->consistent_iovad);
>> if (ret)
>> goto err_iovad_consistent;
>>
>> diff --git a/include/linux/iova.h b/include/linux/iova.h
>> index 02f7222fa85a..56281434ce0c 100644
>> --- a/include/linux/iova.h
>> +++ b/include/linux/iova.h
>> @@ -95,7 +95,8 @@ struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo,
>> unsigned long pfn_hi);
>> void init_iova_domain(struct iova_domain *iovad, unsigned long granule,
>> unsigned long start_pfn);
>> -int iova_domain_init_rcaches(struct iova_domain *iovad);
>> +int iova_domain_init_rcaches(struct iova_domain *iovad, unsigned long iova_len);
>> +int iova_domain_init_rcaches_default(struct iova_domain *iovad);
>> struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
>> void put_iova_domain(struct iova_domain *iovad);
>> #else
>>
>

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