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From: Dmitry Osipenko <digetx@gmail.com>
To: Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v1 8/9] iommu: Introduce iotlb_sync_map callback
Date: Fri, 11 May 2018 22:58:59 +0300	[thread overview]
Message-ID: <fd1fc335-bd06-d7ac-7839-786957144cf8@gmail.com> (raw)
In-Reply-To: <da823a61-5bda-042b-c61f-d0d98f9b6e6f@arm.com>

On 11.05.2018 16:02, Robin Murphy wrote:
> On 08/05/18 19:16, Dmitry Osipenko wrote:
>> Introduce iotlb_sync_map() callback that is invoked in the end of
>> iommu_map(). This new callback allows IOMMU drivers to avoid syncing
>> on mapping of each contiguous chunk and sync only when whole mapping
>> is completed, optimizing performance of the mapping operation.
> 
> This looks like a reasonable compromise - for users of
> IO_PGTABLE_QUIRK_TLBI_ON_MAP we can leave the implicit add_flush() in place for
> each individual map call, but at least move the sync() out to this callback,
> which should still be beneficial overall.
> 
> Modulo one possible nit below,
> 
> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> 
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>   drivers/iommu/iommu.c | 8 ++++++--
>>   include/linux/iommu.h | 1 +
>>   2 files changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index d2aa23202bb9..39b2ee66aa96 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -1508,13 +1508,14 @@ static size_t iommu_pgsize(struct iommu_domain *domain,
>>   int iommu_map(struct iommu_domain *domain, unsigned long iova,
>>             phys_addr_t paddr, size_t size, int prot)
>>   {
>> +    const struct iommu_ops *ops = domain->ops;
>>       unsigned long orig_iova = iova;
>>       unsigned int min_pagesz;
>>       size_t orig_size = size;
>>       phys_addr_t orig_paddr = paddr;
>>       int ret = 0;
>>   -    if (unlikely(domain->ops->map == NULL ||
>> +    if (unlikely(ops->map == NULL ||
>>                domain->pgsize_bitmap == 0UL))
>>           return -ENODEV;
>>   @@ -1543,7 +1544,7 @@ int iommu_map(struct iommu_domain *domain, unsigned
>> long iova,
>>           pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
>>                iova, &paddr, pgsize);
>>   -        ret = domain->ops->map(domain, iova, paddr, pgsize, prot);
>> +        ret = ops->map(domain, iova, paddr, pgsize, prot);
>>           if (ret)
>>               break;
>>   @@ -1552,6 +1553,9 @@ int iommu_map(struct iommu_domain *domain, unsigned
>> long iova,
>>           size -= pgsize;
>>       }
>>   +    if (ops->iotlb_sync_map)
>> +        ops->iotlb_sync_map(domain);
> 
> Is it worth trying to skip this in the error case when we're just going to undo
> it immediately?

I can imagine an IOMMU driver that could handle syncing of mapping differently
from the unmapping, in this case it may not worth skipping sync_map in the error
case.

  reply	other threads:[~2018-05-11 20:09 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-08 18:16 [PATCH v1 0/9] Tegra GART driver clean up and optimization Dmitry Osipenko
2018-05-08 18:16 ` [PATCH v1 1/9] memory: tegra: Provide facility for integration with the GART driver Dmitry Osipenko
2018-05-08 18:16 ` [PATCH v1 2/9] iommu/tegra: gart: Provide access to Memory Controller driver Dmitry Osipenko
2018-05-08 18:16 ` [PATCH v1 3/9] iommu/tegra: gart: Remove code related to module unloading Dmitry Osipenko
2018-05-08 18:16 ` [PATCH v1 4/9] iommu/tegra: gart: Remove pr_fmt and clean up includes Dmitry Osipenko
2018-05-08 18:16 ` [PATCH v1 5/9] iommu/tegra: gart: Clean up driver probe failure unwinding Dmitry Osipenko
2018-05-08 18:16 ` [PATCH v1 6/9] iommu/tegra: gart: Ignore devices without IOMMU phandle in DT Dmitry Osipenko
2018-05-11 11:34   ` Robin Murphy
2018-05-11 15:34     ` Dmitry Osipenko
2018-05-08 18:16 ` [PATCH v1 7/9] iommu/tegra: gart: Provide single domain and group for all devices Dmitry Osipenko
2018-05-11 11:12   ` Dmitry Osipenko
2018-05-11 12:32   ` Robin Murphy
2018-05-11 20:05     ` Dmitry Osipenko
2018-05-14 18:18       ` Robin Murphy
2018-05-16 13:43         ` Dmitry Osipenko
2018-05-08 18:16 ` [PATCH v1 8/9] iommu: Introduce iotlb_sync_map callback Dmitry Osipenko
2018-05-11 13:02   ` Robin Murphy
2018-05-11 19:58     ` Dmitry Osipenko [this message]
2018-05-08 18:17 ` [PATCH v1 9/9] iommu/tegra: gart: Optimize mapping / unmapping performance Dmitry Osipenko

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