Re: [PATCH kernel v8 03/10] powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal

[Alex Williamson]

On Fri, 10 Mar 2017 14:53:30 +1100
Alexey Kardashevskiy  wrote:

> At the moment iommu_table can be disposed by either calling
> iommu_table_free() directly or it_ops::free(); the only implementation
> of free() is in IODA2 - pnv_ioda2_table_free() - and it calls
> iommu_table_free() anyway.
> 
> As we are going to have reference counting on tables, we need an unified
> way of disposing tables.
> 
> This moves it_ops::free() call into iommu_free_table() and makes use
> of the latter. The free() callback now handles only platform-specific
> data.
> 
> As from now on the iommu_free_table() calls it_ops->free(), we need
> to have it_ops initialized before calling iommu_free_table() so this
> moves this initialization in pnv_pci_ioda2_create_table().
> 
> This should cause no behavioral change.
> 
> Signed-off-by: Alexey Kardashevskiy 
> Reviewed-by: David Gibson 
> ---
> Changes:
> v5:
> * moved "tbl->it_ops = _ioda2_iommu_ops" earlier and updated
> the commit log
> ---
>  arch/powerpc/kernel/iommu.c   |  4 
>  arch/powerpc/platforms/powernv/pci-ioda.c | 10 --
>  drivers/vfio/vfio_iommu_spapr_tce.c   |  2 +-
>  3 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index 9bace5df05d5..bc142d87130f 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -719,6 +719,9 @@ void iommu_free_table(struct iommu_table *tbl, const char 
> *node_name)
>   if (!tbl)
>   return;
>  
> + if (tbl->it_ops->free)
> + tbl->it_ops->free(tbl);
> +
>   if (!tbl->it_map) {
>   kfree(tbl);
>   return;
> @@ -745,6 +748,7 @@ void iommu_free_table(struct iommu_table *tbl, const char 
> *node_name)
>   /* free table */
>   kfree(tbl);
>  }
> +EXPORT_SYMBOL_GPL(iommu_free_table);

A slightly cringe worthy generically named export in arch code.

>  
>  /* Creates TCEs for a user provided buffer.  The user buffer must be
>   * contiguous real kernel storage (not vmalloc).  The address passed here
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c 
> b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 69c40b43daa3..7916d0cb05fe 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1425,7 +1425,6 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev 
> *dev, struct pnv_ioda_pe
>   iommu_group_put(pe->table_group.group);
>   BUG_ON(pe->table_group.group);
>   }
> - pnv_pci_ioda2_table_free_pages(tbl);
>   iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
>  }
>  
> @@ -2041,7 +2040,6 @@ static void pnv_ioda2_tce_free(struct iommu_table *tbl, 
> long index,
>  static void pnv_ioda2_table_free(struct iommu_table *tbl)
>  {
>   pnv_pci_ioda2_table_free_pages(tbl);
> - iommu_free_table(tbl, "pnv");
>  }
>  
>  static struct iommu_table_ops pnv_ioda2_iommu_ops = {
> @@ -2318,6 +2316,8 @@ static long pnv_pci_ioda2_create_table(struct 
> iommu_table_group *table_group,
>   if (!tbl)
>   return -ENOMEM;
>  
> + tbl->it_ops = _ioda2_iommu_ops;
> +
>   ret = pnv_pci_ioda2_table_alloc_pages(nid,
>   bus_offset, page_shift, window_size,
>   levels, tbl);
> @@ -2326,8 +2326,6 @@ static long pnv_pci_ioda2_create_table(struct 
> iommu_table_group *table_group,
>   return ret;
>   }
>  
> - tbl->it_ops = _ioda2_iommu_ops;
> -
>   *ptbl = tbl;
>  
>   return 0;
> @@ -2368,7 +2366,7 @@ static long pnv_pci_ioda2_setup_default_config(struct 
> pnv_ioda_pe *pe)
>   if (rc) {
>   pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n",
>   rc);
> - pnv_ioda2_table_free(tbl);
> + iommu_free_table(tbl, "");
>   return rc;
>   }
>  
> @@ -2456,7 +2454,7 @@ static void pnv_ioda2_take_ownership(struct 
> iommu_table_group *table_group)
>   pnv_pci_ioda2_unset_window(>table_group, 0);
>   if (pe->pbus)
>   pnv_ioda_setup_bus_dma(pe, pe->pbus, false);
> - pnv_ioda2_table_free(tbl);
> + iommu_free_table(tbl, "pnv");
>  }
>  
>  static void pnv_ioda2_release_ownership(struct iommu_table_group 
> *table_group)
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c 
> b/drivers/vfio/vfio_iommu_spapr_tce.c
> index cf3de91fbfe7..fbec7348a7e5 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -680,7 +680,7 @@ static void tce_iommu_free_table(struct tce_container 
> *container,
>   unsigned long pages = tbl->it_allocated_size >> PAGE_SHIFT;
>  
>   tce_iommu_userspace_view_free(tbl, container->mm);
> - tbl->it_ops->free(tbl);
> + iommu_free_table(tbl, "");
>   decrement_locked_vm(container->mm, pages);
>  }
>  

Acked-by: Alex 

[PATCH kernel v8 03/10] powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposal

[Alexey Kardashevskiy]

At the moment iommu_table can be disposed by either calling
iommu_table_free() directly or it_ops::free(); the only implementation
of free() is in IODA2 - pnv_ioda2_table_free() - and it calls
iommu_table_free() anyway.

As we are going to have reference counting on tables, we need an unified
way of disposing tables.

This moves it_ops::free() call into iommu_free_table() and makes use
of the latter. The free() callback now handles only platform-specific
data.

As from now on the iommu_free_table() calls it_ops->free(), we need
to have it_ops initialized before calling iommu_free_table() so this
moves this initialization in pnv_pci_ioda2_create_table().

This should cause no behavioral change.

Signed-off-by: Alexey Kardashevskiy 
Reviewed-by: David Gibson 
---
Changes:
v5:
* moved "tbl->it_ops = _ioda2_iommu_ops" earlier and updated
the commit log
---
 arch/powerpc/kernel/iommu.c   |  4 
 arch/powerpc/platforms/powernv/pci-ioda.c | 10 --
 drivers/vfio/vfio_iommu_spapr_tce.c   |  2 +-
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 9bace5df05d5..bc142d87130f 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -719,6 +719,9 @@ void iommu_free_table(struct iommu_table *tbl, const char 
*node_name)
if (!tbl)
return;
 
+   if (tbl->it_ops->free)
+   tbl->it_ops->free(tbl);
+
if (!tbl->it_map) {
kfree(tbl);
return;
@@ -745,6 +748,7 @@ void iommu_free_table(struct iommu_table *tbl, const char 
*node_name)
/* free table */
kfree(tbl);
 }
+EXPORT_SYMBOL_GPL(iommu_free_table);
 
 /* Creates TCEs for a user provided buffer.  The user buffer must be
  * contiguous real kernel storage (not vmalloc).  The address passed here
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c 
b/arch/powerpc/platforms/powernv/pci-ioda.c
index 69c40b43daa3..7916d0cb05fe 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1425,7 +1425,6 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev 
*dev, struct pnv_ioda_pe
iommu_group_put(pe->table_group.group);
BUG_ON(pe->table_group.group);
}
-   pnv_pci_ioda2_table_free_pages(tbl);
iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
 }
 
@@ -2041,7 +2040,6 @@ static void pnv_ioda2_tce_free(struct iommu_table *tbl, 
long index,
 static void pnv_ioda2_table_free(struct iommu_table *tbl)
 {
pnv_pci_ioda2_table_free_pages(tbl);
-   iommu_free_table(tbl, "pnv");
 }
 
 static struct iommu_table_ops pnv_ioda2_iommu_ops = {
@@ -2318,6 +2316,8 @@ static long pnv_pci_ioda2_create_table(struct 
iommu_table_group *table_group,
if (!tbl)
return -ENOMEM;
 
+   tbl->it_ops = _ioda2_iommu_ops;
+
ret = pnv_pci_ioda2_table_alloc_pages(nid,
bus_offset, page_shift, window_size,
levels, tbl);
@@ -2326,8 +2326,6 @@ static long pnv_pci_ioda2_create_table(struct 
iommu_table_group *table_group,
return ret;
}
 
-   tbl->it_ops = _ioda2_iommu_ops;
-
*ptbl = tbl;
 
return 0;
@@ -2368,7 +2366,7 @@ static long pnv_pci_ioda2_setup_default_config(struct 
pnv_ioda_pe *pe)
if (rc) {
pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n",
rc);
-   pnv_ioda2_table_free(tbl);
+   iommu_free_table(tbl, "");
return rc;
}
 
@@ -2456,7 +2454,7 @@ static void pnv_ioda2_take_ownership(struct 
iommu_table_group *table_group)
pnv_pci_ioda2_unset_window(>table_group, 0);
if (pe->pbus)
pnv_ioda_setup_bus_dma(pe, pe->pbus, false);
-   pnv_ioda2_table_free(tbl);
+   iommu_free_table(tbl, "pnv");
 }
 
 static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c 
b/drivers/vfio/vfio_iommu_spapr_tce.c
index cf3de91fbfe7..fbec7348a7e5 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -680,7 +680,7 @@ static void tce_iommu_free_table(struct tce_container 
*container,
unsigned long pages = tbl->it_allocated_size >> PAGE_SHIFT;
 
tce_iommu_userspace_view_free(tbl, container->mm);
-   tbl->it_ops->free(tbl);
+   iommu_free_table(tbl, "");
decrement_locked_vm(container->mm, pages);
 }
 
-- 
2.11.0