[PATCH 4.9 65/93] powerpc/iommu: Stop using @current in mm_iommu_xxx

From: Greg Kroah-Hartman
Date: Mon Mar 20 2017 - 14:21:51 EST

4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Alexey Kardashevskiy <aik@xxxxxxxxx>

[ Upstream commit d7baee6901b34c4895eb78efdbf13a49079d7404 ]

This changes mm_iommu_xxx helpers to take mm_struct as a parameter
instead of getting it from @current which in some situations may
not have a valid reference to mm.

This changes helpers to receive @mm and moves all references to @current
to the caller, including checks for !current and !current->mm;
checks in mm_iommu_preregistered() are removed as there is no caller
yet.

This moves the mm_iommu_adjust_locked_vm() call to the caller as
it receives mm_iommu_table_group_mem_t but it needs mm.

This should cause no behavioral change.

Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Acked-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/mmu_context.h | 16 ++++++-----
arch/powerpc/mm/mmu_context_iommu.c | 46 ++++++++++++---------------------
drivers/vfio/vfio_iommu_spapr_tce.c | 14 +++++++---
3 files changed, 36 insertions(+), 40 deletions(-)

--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -19,16 +19,18 @@ extern void destroy_context(struct mm_st
struct mm_iommu_table_group_mem_t;

extern int isolate_lru_page(struct page *page); /* from internal.h */
-extern bool mm_iommu_preregistered(void);
-extern long mm_iommu_get(unsigned long ua, unsigned long entries,
+extern bool mm_iommu_preregistered(struct mm_struct *mm);
+extern long mm_iommu_get(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_iommu_table_group_mem_t *mem);
+extern long mm_iommu_put(struct mm_struct *mm,
+ struct mm_iommu_table_group_mem_t *mem);
extern void mm_iommu_init(struct mm_struct *mm);
extern void mm_iommu_cleanup(struct mm_struct *mm);
-extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua,
- unsigned long size);
-extern struct mm_iommu_table_group_mem_t *mm_iommu_find(unsigned long ua,
- unsigned long entries);
+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_find(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 long *hpa);
extern long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem);
--- a/arch/powerpc/mm/mmu_context_iommu.c
+++ b/arch/powerpc/mm/mmu_context_iommu.c
@@ -56,7 +56,7 @@ static long mm_iommu_adjust_locked_vm(st
}

pr_debug("[%d] RLIMIT_MEMLOCK HASH64 %c%ld %ld/%ld\n",
- current->pid,
+ current ? current->pid : 0,
incr ? '+' : '-',
npages << PAGE_SHIFT,
mm->locked_vm << PAGE_SHIFT,
@@ -66,12 +66,9 @@ static long mm_iommu_adjust_locked_vm(st
return ret;
}

-bool mm_iommu_preregistered(void)
+bool mm_iommu_preregistered(struct mm_struct *mm)
{
- if (!current || !current->mm)
- return false;
-
- return !list_empty(&current->mm->context.iommu_group_mem_list);
+ return !list_empty(&mm->context.iommu_group_mem_list);
}
EXPORT_SYMBOL_GPL(mm_iommu_preregistered);

@@ -124,19 +121,16 @@ static int mm_iommu_move_page_from_cma(s
return 0;
}

-long mm_iommu_get(unsigned long ua, unsigned long entries,
+long mm_iommu_get(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;
long i, j, ret = 0, locked_entries = 0;
struct page *page = NULL;

- if (!current || !current->mm)
- return -ESRCH; /* process exited */
-
mutex_lock(&mem_list_mutex);

- list_for_each_entry_rcu(mem, &current->mm->context.iommu_group_mem_list,
+ list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list,
next) {
if ((mem->ua == ua) && (mem->entries == entries)) {
++mem->used;
@@ -154,7 +148,7 @@ long mm_iommu_get(unsigned long ua, unsi

}

- ret = mm_iommu_adjust_locked_vm(current->mm, entries, true);
+ ret = mm_iommu_adjust_locked_vm(mm, entries, true);
if (ret)
goto unlock_exit;

@@ -215,11 +209,11 @@ populate:
mem->entries = entries;
*pmem = mem;

- list_add_rcu(&mem->next, &current->mm->context.iommu_group_mem_list);
+ list_add_rcu(&mem->next, &mm->context.iommu_group_mem_list);

unlock_exit:
if (locked_entries && ret)
- mm_iommu_adjust_locked_vm(current->mm, locked_entries, false);
+ mm_iommu_adjust_locked_vm(mm, locked_entries, false);

mutex_unlock(&mem_list_mutex);

@@ -264,17 +258,13 @@ static void mm_iommu_free(struct rcu_hea
static void mm_iommu_release(struct mm_iommu_table_group_mem_t *mem)
{
list_del_rcu(&mem->next);
- mm_iommu_adjust_locked_vm(current->mm, mem->entries, false);
call_rcu(&mem->rcu, mm_iommu_free);
}

-long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem)
+long mm_iommu_put(struct mm_struct *mm, struct mm_iommu_table_group_mem_t *mem)
{
long ret = 0;

- if (!current || !current->mm)
- return -ESRCH; /* process exited */
-
mutex_lock(&mem_list_mutex);

if (mem->used == 0) {
@@ -297,6 +287,8 @@ long mm_iommu_put(struct mm_iommu_table_
/* @mapped became 0 so now mappings are disabled, release the region */
mm_iommu_release(mem);

+ mm_iommu_adjust_locked_vm(mm, mem->entries, false);
+
unlock_exit:
mutex_unlock(&mem_list_mutex);

@@ -304,14 +296,12 @@ unlock_exit:
}
EXPORT_SYMBOL_GPL(mm_iommu_put);

-struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua,
- unsigned long size)
+struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
+ unsigned long ua, unsigned long size)
{
struct mm_iommu_table_group_mem_t *mem, *ret = NULL;

- list_for_each_entry_rcu(mem,
- &current->mm->context.iommu_group_mem_list,
- next) {
+ list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
if ((mem->ua <= ua) &&
(ua + size <= mem->ua +
(mem->entries << PAGE_SHIFT))) {
@@ -324,14 +314,12 @@ struct mm_iommu_table_group_mem_t *mm_io
}
EXPORT_SYMBOL_GPL(mm_iommu_lookup);

-struct mm_iommu_table_group_mem_t *mm_iommu_find(unsigned long ua,
- unsigned long entries)
+struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
+ unsigned long ua, unsigned long entries)
{
struct mm_iommu_table_group_mem_t *mem, *ret = NULL;

- list_for_each_entry_rcu(mem,
- &current->mm->context.iommu_group_mem_list,
- next) {
+ list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
if ((mem->ua == ua) && (mem->entries == entries)) {
ret = mem;
break;
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -107,14 +107,17 @@ static long tce_iommu_unregister_pages(s
{
struct mm_iommu_table_group_mem_t *mem;

+ if (!current || !current->mm)
+ return -ESRCH; /* process exited */
+
if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
return -EINVAL;

- mem = mm_iommu_find(vaddr, size >> PAGE_SHIFT);
+ mem = mm_iommu_find(current->mm, vaddr, size >> PAGE_SHIFT);
if (!mem)
return -ENOENT;

- return mm_iommu_put(mem);
+ return mm_iommu_put(current->mm, mem);
}

static long tce_iommu_register_pages(struct tce_container *container,
@@ -124,11 +127,14 @@ static long tce_iommu_register_pages(str
struct mm_iommu_table_group_mem_t *mem = NULL;
unsigned long entries = size >> PAGE_SHIFT;

+ if (!current || !current->mm)
+ return -ESRCH; /* process exited */
+
if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK) ||
((vaddr + size) < vaddr))
return -EINVAL;

- ret = mm_iommu_get(vaddr, entries, &mem);
+ ret = mm_iommu_get(current->mm, vaddr, entries, &mem);
if (ret)
return ret;

@@ -375,7 +381,7 @@ static int tce_iommu_prereg_ua_to_hpa(un
long ret = 0;
struct mm_iommu_table_group_mem_t *mem;

- mem = mm_iommu_lookup(tce, size);
+ mem = mm_iommu_lookup(current->mm, tce, size);
if (!mem)
return -EINVAL;