Re: [PATCH RESEND v5 5/5] iova: Add iova_len argument to iova_domain_init_rcaches()

Thu, 07 Apr 2022 06:52:54 -0700 

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 <[email protected]>
---
  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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