[PATCH 2/8] dma-buf: fix shared fence list handling in reservation_object_copy_fences
Christian König
ckoenig.leichtzumerken at gmail.com
Tue Aug 6 15:01:28 UTC 2019
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 at amd.com>
---
drivers/dma-buf/reservation.c | 65 +++++++++++++++++++++++++----------
1 file changed, 46 insertions(+), 19 deletions(-)
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c
index d59207ca72d2..c0ba05936ab6 100644
--- a/drivers/dma-buf/reservation.c
+++ b/drivers/dma-buf/reservation.c
@@ -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 @@ int reservation_object_copy_fences(struct reservation_object *dst,
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 @@ int reservation_object_copy_fences(struct reservation_object *dst,
}
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 @@ int reservation_object_copy_fences(struct reservation_object *dst,
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 @@ int reservation_object_copy_fences(struct reservation_object *dst,
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;
--
2.17.1
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