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dma-buf: add reservation_object_copy_fences (v2)

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Allows us to copy all the fences in a reservation object to another one.

v2: handle NULL src_list

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1502384509-10465-2-git-send-email-alexander.deucher@amd.com
This commit is contained in:
Christian König 2017-08-10 13:01:48 -04:00 committed by Alex Deucher
parent eac99d4a20
commit 7faf952a30
2 changed files with 63 additions and 0 deletions
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60
drivers/dma-buf/reservation.c
View File

@ -261,6 +261,66 @@ void reservation_object_add_excl_fence(struct reservation_object *obj,
}
EXPORT_SYMBOL(reservation_object_add_excl_fence);
/**
* reservation_object_copy_fences - Copy all fences from src to dst.
* @dst: the destination reservation object
* @src: the source reservation object
*
* Copy all fences from src to dst. Both src->lock as well as dst-lock must be
* held.
*/
int reservation_object_copy_fences(struct reservation_object *dst,
struct reservation_object *src)
{
struct reservation_object_list *src_list, *dst_list;
struct dma_fence *old, *new;
size_t size;
unsigned i;
src_list = reservation_object_get_list(src);
if (src_list) {
size = offsetof(typeof(*src_list),
shared[src_list->shared_count]);
dst_list = kmalloc(size, GFP_KERNEL);
if (!dst_list)
return -ENOMEM;
dst_list->shared_count = src_list->shared_count;
dst_list->shared_max = src_list->shared_count;
for (i = 0; i < src_list->shared_count; ++i)
dst_list->shared[i] =
dma_fence_get(src_list->shared[i]);
} else {
dst_list = NULL;
}
kfree(dst->staged);
dst->staged = NULL;
src_list = reservation_object_get_list(dst);
old = reservation_object_get_excl(dst);
new = reservation_object_get_excl(src);
dma_fence_get(new);
preempt_disable();
write_seqcount_begin(&dst->seq);
/* write_seqcount_begin provides the necessary memory barrier */
RCU_INIT_POINTER(dst->fence_excl, new);
RCU_INIT_POINTER(dst->fence, dst_list);
write_seqcount_end(&dst->seq);
preempt_enable();
if (src_list)
kfree_rcu(src_list, rcu);
dma_fence_put(old);
return 0;
}
EXPORT_SYMBOL(reservation_object_copy_fences);
/**
* reservation_object_get_fences_rcu - Get an object's shared and exclusive
* fences without update side lock held

3
include/linux/reservation.h
View File

@ -254,6 +254,9 @@ int reservation_object_get_fences_rcu(struct reservation_object *obj,
unsigned *pshared_count,
struct dma_fence ***pshared);
int reservation_object_copy_fences(struct reservation_object *dst,
struct reservation_object *src);
long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
bool wait_all, bool intr,
unsigned long timeout);