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dma-buf: fix shared fence list handling in reservation_object_copy_fences 

Add some helpers to correctly allocate/free reservation_object_lists.

Otherwise we might forget to drop dma_fence references on list destruction.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/322031/?series=64786&rev=1
This commit is contained in:
Christian König 2019-08-06 13:33:12 +02:00
parent 93505ee7d0
commit 96e95496b0
1 changed files with 46 additions and 19 deletions
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65
drivers/dma-buf/reservation.c
View File

@ -55,6 +55,47 @@ EXPORT_SYMBOL(reservation_seqcount_class);
const char reservation_seqcount_string[] = "reservation_seqcount";
EXPORT_SYMBOL(reservation_seqcount_string);
/**
* reservation_object_list_alloc - allocate fence list
* @shared_max: number of fences we need space for
*
* Allocate a new reservation_object_list and make sure to correctly initialize
* shared_max.
*/
static struct reservation_object_list *
reservation_object_list_alloc(unsigned int shared_max)
{
struct reservation_object_list *list;
list = kmalloc(offsetof(typeof(*list), shared[shared_max]), GFP_KERNEL);
if (!list)
return NULL;
list->shared_max = (ksize(list) - offsetof(typeof(*list), shared)) /
sizeof(*list->shared);
return list;
}
/**
* reservation_object_list_free - free fence list
* @list: list to free
*
* Free a reservation_object_list and make sure to drop all references.
*/
static void reservation_object_list_free(struct reservation_object_list *list)
{
unsigned int i;
if (!list)
return;
for (i = 0; i < list->shared_count; ++i)
dma_fence_put(rcu_dereference_protected(list->shared[i], true));
kfree_rcu(list, rcu);
}
/**
* reservation_object_init - initialize a reservation object
* @obj: the reservation object
@ -76,7 +117,6 @@ EXPORT_SYMBOL(reservation_object_init);
*/
void reservation_object_fini(struct reservation_object *obj)
{
int i;
struct reservation_object_list *fobj;
struct dma_fence *excl;
@ -89,13 +129,7 @@ void reservation_object_fini(struct reservation_object *obj)
dma_fence_put(excl);
fobj = rcu_dereference_protected(obj->fence, 1);
if (fobj) {
for (i = 0; i < fobj->shared_count; ++i)
dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1));
kfree(fobj);
}
reservation_object_list_free(fobj);
ww_mutex_destroy(&obj->lock);
}
EXPORT_SYMBOL(reservation_object_fini);
@ -132,7 +166,7 @@ int reservation_object_reserve_shared(struct reservation_object *obj,
max = 4;
}
new = kmalloc(offsetof(typeof(*new), shared[max]), GFP_KERNEL);
new = reservation_object_list_alloc(max);
if (!new)
return -ENOMEM;
@ -153,9 +187,6 @@ int reservation_object_reserve_shared(struct reservation_object *obj,
RCU_INIT_POINTER(new->shared[j++], fence);
}
new->shared_count = j;
new->shared_max =
(ksize(new) - offsetof(typeof(*new), shared)) /
sizeof(*new->shared);
/*
* We are not changing the effective set of fences here so can
@ -286,7 +317,6 @@ int reservation_object_copy_fences(struct reservation_object *dst,
{
struct reservation_object_list *src_list, *dst_list;
struct dma_fence *old, *new;
size_t size;
unsigned i;
reservation_object_assert_held(dst);
@ -298,10 +328,9 @@ retry:
if (src_list) {
unsigned shared_count = src_list->shared_count;
size = offsetof(typeof(*src_list), shared[shared_count]);
rcu_read_unlock();
dst_list = kmalloc(size, GFP_KERNEL);
dst_list = reservation_object_list_alloc(shared_count);
if (!dst_list)
return -ENOMEM;
@ -313,7 +342,6 @@ retry:
}
dst_list->shared_count = 0;
dst_list->shared_max = shared_count;
for (i = 0; i < src_list->shared_count; ++i) {
struct dma_fence *fence;
@ -323,7 +351,7 @@ retry:
continue;
if (!dma_fence_get_rcu(fence)) {
kfree(dst_list);
reservation_object_list_free(dst_list);
src_list = rcu_dereference(src->fence);
goto retry;
}
@ -353,8 +381,7 @@ retry:
write_seqcount_end(&dst->seq);
preempt_enable();
if (src_list)
kfree_rcu(src_list, rcu);
reservation_object_list_free(src_list);
dma_fence_put(old);
return 0;