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powerpc/iommu: Stop using @current in mm_iommu_xxx
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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@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Alexey Kardashevskiy authored and Michael Ellerman committed Dec 2, 2016
1 parent 88f54a3 commit d7baee6
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Showing 3 changed files with 36 additions and 40 deletions.
16 changes: 9 additions & 7 deletions arch/powerpc/include/asm/mmu_context.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,16 +19,18 @@ extern void destroy_context(struct mm_struct *mm);
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);
Expand Down
46 changes: 17 additions & 29 deletions arch/powerpc/mm/mmu_context_iommu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ static long mm_iommu_adjust_locked_vm(struct mm_struct *mm,
}

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,
Expand All @@ -66,12 +66,9 @@ static long mm_iommu_adjust_locked_vm(struct mm_struct *mm,
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);

Expand Down Expand Up @@ -124,19 +121,16 @@ static int mm_iommu_move_page_from_cma(struct page *page)
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;
Expand All @@ -154,7 +148,7 @@ long mm_iommu_get(unsigned long ua, unsigned long entries,

}

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

Expand Down Expand Up @@ -215,11 +209,11 @@ long mm_iommu_get(unsigned long ua, unsigned long entries,
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);

Expand Down Expand Up @@ -264,17 +258,13 @@ static void mm_iommu_free(struct rcu_head *head)
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) {
Expand All @@ -297,21 +287,21 @@ long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem)
/* @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);

return ret;
}
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))) {
Expand All @@ -324,14 +314,12 @@ struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua,
}
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;
Expand Down
14 changes: 10 additions & 4 deletions drivers/vfio/vfio_iommu_spapr_tce.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -107,14 +107,17 @@ static long tce_iommu_unregister_pages(struct tce_container *container,
{
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,
Expand All @@ -124,11 +127,14 @@ static long tce_iommu_register_pages(struct tce_container *container,
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;

Expand Down Expand Up @@ -375,7 +381,7 @@ static int tce_iommu_prereg_ua_to_hpa(unsigned long tce, unsigned long size,
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;

Expand Down

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