Re: [PATCH kernel v3 02/22] powerpc/mm/iommu/vfio_spapr_tce: Change mm_iommu_get to reference a region
On Tue, Nov 13, 2018 at 07:28:03PM +1100, Alexey Kardashevskiy wrote:
> Normally mm_iommu_get() is supposed to add a reference and
> mm_iommu_put() to remove it. However historically mm_iommu_find() does
> the referencing and mm_iommu_get() is doing allocation and referencing.
>
> We are going to add another helper to preregister device memory so
> instead of having mm_iommu_new() which pre-registers the normal memory
> and references the region, we need separate helpers for pre-registering
> and referencing.
>
> This renames:
> - mm_iommu_get to mm_iommu_new;
> - mm_iommu_find to mm_iommu_get.
>
> To make the mm_iommu_get name reflect what it is supposed to do, this
> changes mm_iommu_get() to reference the region so from now on for every
> mm_iommu_get() we need a matching mm_iommu_put().
>
> Signed-off-by: Alexey Kardashevskiy
Reviewed-by: David Gibson
> ---
> Changes:
> v2:
> * merged 2 patches into one
> ---
> arch/powerpc/include/asm/mmu_context.h | 4 +--
> arch/powerpc/mm/mmu_context_iommu.c| 13 ++---
> drivers/vfio/vfio_iommu_spapr_tce.c| 37 +-
> 3 files changed, 35 insertions(+), 19 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/mmu_context.h
> b/arch/powerpc/include/asm/mmu_context.h
> index 0381394..2d6b00d 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -21,7 +21,7 @@ struct mm_iommu_table_group_mem_t;
>
> extern int isolate_lru_page(struct page *page); /* from internal.h */
> extern bool mm_iommu_preregistered(struct mm_struct *mm);
> -extern long mm_iommu_get(struct mm_struct *mm,
> +extern long mm_iommu_new(struct mm_struct *mm,
> unsigned long ua, unsigned long entries,
> struct mm_iommu_table_group_mem_t **pmem);
> extern long mm_iommu_put(struct mm_struct *mm,
> @@ -32,7 +32,7 @@ extern struct mm_iommu_table_group_mem_t
> *mm_iommu_lookup(struct mm_struct *mm,
> unsigned long ua, unsigned long size);
> extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(
> struct mm_struct *mm, unsigned long ua, unsigned long size);
> -extern struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
> +extern struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm,
> unsigned long ua, unsigned long entries);
> extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
> unsigned long ua, unsigned int pageshift, unsigned long *hpa);
> diff --git a/arch/powerpc/mm/mmu_context_iommu.c
> b/arch/powerpc/mm/mmu_context_iommu.c
> index 1d5161f..babc6ad 100644
> --- a/arch/powerpc/mm/mmu_context_iommu.c
> +++ b/arch/powerpc/mm/mmu_context_iommu.c
> @@ -89,7 +89,7 @@ bool mm_iommu_preregistered(struct mm_struct *mm)
> }
> EXPORT_SYMBOL_GPL(mm_iommu_preregistered);
>
> -long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long
> entries,
> +long mm_iommu_new(struct mm_struct *mm, unsigned long ua, unsigned long
> entries,
> struct mm_iommu_table_group_mem_t **pmem)
> {
> struct mm_iommu_table_group_mem_t *mem;
> @@ -202,7 +202,7 @@ long mm_iommu_get(struct mm_struct *mm, unsigned long ua,
> unsigned long entries,
>
> return ret;
> }
> -EXPORT_SYMBOL_GPL(mm_iommu_get);
> +EXPORT_SYMBOL_GPL(mm_iommu_new);
>
> static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem)
> {
> @@ -318,21 +318,26 @@ struct mm_iommu_table_group_mem_t
> *mm_iommu_lookup_rm(struct mm_struct *mm,
> return ret;
> }
>
> -struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
> +struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm,
> unsigned long ua, unsigned long entries)
> {
> struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
>
> + mutex_lock(_list_mutex);
> +
> list_for_each_entry_rcu(mem, >context.iommu_group_mem_list, next) {
> if ((mem->ua == ua) && (mem->entries == entries)) {
> ret = mem;
> + ++mem->used;
> break;
> }
> }
>
> + mutex_unlock(_list_mutex);
> +
> return ret;
> }
> -EXPORT_SYMBOL_GPL(mm_iommu_find);
> +EXPORT_SYMBOL_GPL(mm_iommu_get);
>
> long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
> unsigned long ua, unsigned int pageshift, unsigned long *hpa)
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c
> b/drivers/vfio/vfio_iommu_spapr_tce.c
> index ad63725..56db071 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -151,12 +151,13 @@ static long tce_iommu_unregister_pages(struct
> tce_container *container,
> {
> struct mm_iommu_table_group_mem_t *mem;
> struct tce_iommu_prereg *tcemem;
> - bool found = false;
> + bool found;
> + long ret;
>
> if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
>
[PATCH kernel v3 02/22] powerpc/mm/iommu/vfio_spapr_tce: Change mm_iommu_get to reference a region
Normally mm_iommu_get() is supposed to add a reference and
mm_iommu_put() to remove it. However historically mm_iommu_find() does
the referencing and mm_iommu_get() is doing allocation and referencing.
We are going to add another helper to preregister device memory so
instead of having mm_iommu_new() which pre-registers the normal memory
and references the region, we need separate helpers for pre-registering
and referencing.
This renames:
- mm_iommu_get to mm_iommu_new;
- mm_iommu_find to mm_iommu_get.
To make the mm_iommu_get name reflect what it is supposed to do, this
changes mm_iommu_get() to reference the region so from now on for every
mm_iommu_get() we need a matching mm_iommu_put().
Signed-off-by: Alexey Kardashevskiy
---
Changes:
v2:
* merged 2 patches into one
---
arch/powerpc/include/asm/mmu_context.h | 4 +--
arch/powerpc/mm/mmu_context_iommu.c| 13 ++---
drivers/vfio/vfio_iommu_spapr_tce.c| 37 +-
3 files changed, 35 insertions(+), 19 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu_context.h
b/arch/powerpc/include/asm/mmu_context.h
index 0381394..2d6b00d 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -21,7 +21,7 @@ struct mm_iommu_table_group_mem_t;
extern int isolate_lru_page(struct page *page);/* from internal.h */
extern bool mm_iommu_preregistered(struct mm_struct *mm);
-extern long mm_iommu_get(struct mm_struct *mm,
+extern long mm_iommu_new(struct mm_struct *mm,
unsigned long ua, unsigned long entries,
struct mm_iommu_table_group_mem_t **pmem);
extern long mm_iommu_put(struct mm_struct *mm,
@@ -32,7 +32,7 @@ extern struct mm_iommu_table_group_mem_t
*mm_iommu_lookup(struct mm_struct *mm,
unsigned long ua, unsigned long size);
extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(
struct mm_struct *mm, unsigned long ua, unsigned long size);
-extern struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
+extern struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm,
unsigned long ua, unsigned long entries);
extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
unsigned long ua, unsigned int pageshift, unsigned long *hpa);
diff --git a/arch/powerpc/mm/mmu_context_iommu.c
b/arch/powerpc/mm/mmu_context_iommu.c
index 1d5161f..babc6ad 100644
--- a/arch/powerpc/mm/mmu_context_iommu.c
+++ b/arch/powerpc/mm/mmu_context_iommu.c
@@ -89,7 +89,7 @@ bool mm_iommu_preregistered(struct mm_struct *mm)
}
EXPORT_SYMBOL_GPL(mm_iommu_preregistered);
-long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long
entries,
+long mm_iommu_new(struct mm_struct *mm, unsigned long ua, unsigned long
entries,
struct mm_iommu_table_group_mem_t **pmem)
{
struct mm_iommu_table_group_mem_t *mem;
@@ -202,7 +202,7 @@ long mm_iommu_get(struct mm_struct *mm, unsigned long ua,
unsigned long entries,
return ret;
}
-EXPORT_SYMBOL_GPL(mm_iommu_get);
+EXPORT_SYMBOL_GPL(mm_iommu_new);
static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem)
{
@@ -318,21 +318,26 @@ struct mm_iommu_table_group_mem_t
*mm_iommu_lookup_rm(struct mm_struct *mm,
return ret;
}
-struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
+struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm,
unsigned long ua, unsigned long entries)
{
struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
+ mutex_lock(_list_mutex);
+
list_for_each_entry_rcu(mem, >context.iommu_group_mem_list, next) {
if ((mem->ua == ua) && (mem->entries == entries)) {
ret = mem;
+ ++mem->used;
break;
}
}
+ mutex_unlock(_list_mutex);
+
return ret;
}
-EXPORT_SYMBOL_GPL(mm_iommu_find);
+EXPORT_SYMBOL_GPL(mm_iommu_get);
long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
unsigned long ua, unsigned int pageshift, unsigned long *hpa)
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c
b/drivers/vfio/vfio_iommu_spapr_tce.c
index ad63725..56db071 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -151,12 +151,13 @@ static long tce_iommu_unregister_pages(struct
tce_container *container,
{
struct mm_iommu_table_group_mem_t *mem;
struct tce_iommu_prereg *tcemem;
- bool found = false;
+ bool found;
+ long ret;
if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
return -EINVAL;
- mem = mm_iommu_find(container->mm, vaddr, size >> PAGE_SHIFT);
+ mem = mm_iommu_get(container->mm, vaddr, size >> PAGE_SHIFT);
if (!mem)
return -ENOENT;
@@ -168,9 +169,13 @@ static long tce_iommu_unregister_pages(struct
