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dma-buf: use new iterator in dma_resv_copy_fences

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This makes the function much simpler since the complex
retry logic is now handled else where.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211005113742.1101-5-christian.koenig@amd.com
This commit is contained in:
Christian König 2021-06-15 15:15:01 +02:00
parent c921ff373b
commit 96601e8a47
1 changed files with 34 additions and 54 deletions
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88
drivers/dma-buf/dma-resv.c
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@ -432,74 +432,54 @@ EXPORT_SYMBOL(dma_resv_iter_next_unlocked);
*/
int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
{
struct dma_resv_list *src_list, *dst_list;
struct dma_fence *old, *new;
unsigned int i;
struct dma_resv_iter cursor;
struct dma_resv_list *list;
struct dma_fence *f, *excl;
dma_resv_assert_held(dst);
rcu_read_lock();
src_list = dma_resv_shared_list(src);
list = NULL;
excl = NULL;
retry:
if (src_list) {
unsigned int shared_count = src_list->shared_count;
dma_resv_iter_begin(&cursor, src, true);
dma_resv_for_each_fence_unlocked(&cursor, f) {
rcu_read_unlock();
if (dma_resv_iter_is_restarted(&cursor)) {
dma_resv_list_free(list);
dma_fence_put(excl);
dst_list = dma_resv_list_alloc(shared_count);
if (!dst_list)
return -ENOMEM;
if (cursor.fences) {
unsigned int cnt = cursor.fences->shared_count;
rcu_read_lock();
src_list = dma_resv_shared_list(src);
if (!src_list || src_list->shared_count > shared_count) {
kfree(dst_list);
goto retry;
list = dma_resv_list_alloc(cnt);
if (!list) {
dma_resv_iter_end(&cursor);
return -ENOMEM;
}
list->shared_count = 0;
} else {
list = NULL;
}
excl = NULL;
}
dst_list->shared_count = 0;
for (i = 0; i < src_list->shared_count; ++i) {
struct dma_fence __rcu **dst;
struct dma_fence *fence;
fence = rcu_dereference(src_list->shared[i]);
if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
&fence->flags))
continue;
if (!dma_fence_get_rcu(fence)) {
dma_resv_list_free(dst_list);
src_list = dma_resv_shared_list(src);
goto retry;
}
if (dma_fence_is_signaled(fence)) {
dma_fence_put(fence);
continue;
}
dst = &dst_list->shared[dst_list->shared_count++];
rcu_assign_pointer(*dst, fence);
}
} else {
dst_list = NULL;
dma_fence_get(f);
if (dma_resv_iter_is_exclusive(&cursor))
excl = f;
else
RCU_INIT_POINTER(list->shared[list->shared_count++], f);
}
new = dma_fence_get_rcu_safe(&src->fence_excl);
rcu_read_unlock();
src_list = dma_resv_shared_list(dst);
old = dma_resv_excl_fence(dst);
dma_resv_iter_end(&cursor);
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);
excl = rcu_replace_pointer(dst->fence_excl, excl, dma_resv_held(dst));
list = rcu_replace_pointer(dst->fence, list, dma_resv_held(dst));
write_seqcount_end(&dst->seq);
dma_resv_list_free(src_list);
dma_fence_put(old);
dma_resv_list_free(list);
dma_fence_put(excl);
return 0;
}