From: Christian König ckoenig.leichtzumerken@gmail.com
Add a helper function to get a single fence representing all fences in a dma_resv object.
This fence is either the only one in the object or all not signaled fences of the object in a flatted out dma_fence_array.
v2 (Jason Ekstrand): - Take reference of fences both for creating the dma_fence_array and in the case where we return one fence. - Handle the case where dma_resv_get_list() returns NULL
Signed-off-by: Jason Ekstrand jason@jlekstrand.net --- drivers/dma-buf/dma-resv.c | 118 +++++++++++++++++++++++++++++++++++++ include/linux/dma-resv.h | 3 + 2 files changed, 121 insertions(+)
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 4264e64788c4..66591d8ab7ef 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -33,6 +33,8 @@ */
#include <linux/dma-resv.h> +#include <linux/dma-fence-chain.h> +#include <linux/dma-fence-array.h> #include <linux/export.h> #include <linux/sched/mm.h>
@@ -47,6 +49,19 @@ * write-side updates. */
+/** + * dma_fence_deep_dive_for_each - deep dive into the fence containers + * @fence: resulting fence + * @chain: variable for a dma_fence_chain + * @index: index into a dma_fence_array + * @head: starting point + * + * Helper to deep dive into the fence containers for flattening them. + */ +#define dma_fence_deep_dive_for_each(fence, chain, index, head) \ + dma_fence_chain_for_each(chain, head) \ + dma_fence_array_for_each(fence, index, chain) + DEFINE_WD_CLASS(reservation_ww_class); EXPORT_SYMBOL(reservation_ww_class);
@@ -516,6 +531,109 @@ int dma_resv_get_fences_rcu(struct dma_resv *obj, } EXPORT_SYMBOL_GPL(dma_resv_get_fences_rcu);
+/** + * dma_resv_get_singleton - get a single fence for the dma_resv object + * @obj: the reservation object + * @extra: extra fence to add to the resulting array + * @result: resulting dma_fence + * + * Get a single fence representing all unsignaled fences in the dma_resv object + * plus the given extra fence. If we got only one fence return a new + * reference to that, otherwise return a dma_fence_array object. + * + * RETURNS + * Returns -NOMEM if allocations fail, zero otherwise. + */ +int dma_resv_get_singleton(struct dma_resv *obj, struct dma_fence *extra, + struct dma_fence **result) +{ + struct dma_resv_list *fobj = dma_resv_get_list(obj); + struct dma_fence *excl = dma_resv_get_excl(obj); + struct dma_fence *fence, *chain, **fences; + struct dma_fence_array *array; + unsigned int num_fences, shared_count; + unsigned int i, j; + + num_fences = 0; + *result = NULL; + + dma_fence_deep_dive_for_each(fence, chain, i, extra) { + if (dma_fence_is_signaled(fence)) + continue; + + *result = fence; + ++num_fences; + } + + dma_fence_deep_dive_for_each(fence, chain, i, excl) { + if (dma_fence_is_signaled(fence)) + continue; + + *result = fence; + ++num_fences; + } + + shared_count = fobj ? fobj->shared_count : 0; + for (i = 0; i < shared_count; ++i) { + struct dma_fence *f; + + f = rcu_dereference_protected(fobj->shared[i], + dma_resv_held(obj)); + dma_fence_deep_dive_for_each(fence, chain, j, f) { + if (dma_fence_is_signaled(fence)) + continue; + + *result = fence; + ++num_fences; + } + } + + if (num_fences <= 1) { + *result = dma_fence_get(*result); + return 0; + } + + fences = kmalloc_array(num_fences, sizeof(struct dma_fence*), + GFP_KERNEL); + if (!fences) + return -ENOMEM; + + num_fences = 0; + + dma_fence_deep_dive_for_each(fence, chain, i, extra) + if (!dma_fence_is_signaled(fence)) + fences[num_fences++] = dma_fence_get(fence); + + dma_fence_deep_dive_for_each(fence, chain, i, excl) + if (!dma_fence_is_signaled(fence)) + fences[num_fences++] = dma_fence_get(fence); + + for (i = 0; i < shared_count; ++i) { + struct dma_fence *f; + + f = rcu_dereference_protected(fobj->shared[i], + dma_resv_held(obj)); + dma_fence_deep_dive_for_each(fence, chain, j, f) + if (!dma_fence_is_signaled(fence)) + fences[num_fences++] = dma_fence_get(fence); + } + + array = dma_fence_array_create(num_fences, fences, + dma_fence_context_alloc(1), + 1, false); + if (!array) + goto error_free; + + *result = &array->base; + return 0; + +error_free: + while (num_fences--) + dma_fence_put(fences[num_fences]); + kfree(fences); + return -ENOMEM; +} + /** * dma_resv_wait_timeout_rcu - Wait on reservation's objects * shared and/or exclusive fences. diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index ee50d10f052b..d50e753e4550 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -287,6 +287,9 @@ int dma_resv_get_fences_rcu(struct dma_resv *obj,
int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
+int dma_resv_get_singleton(struct dma_resv *obj, struct dma_fence *extra, + struct dma_fence **result); + long dma_resv_wait_timeout_rcu(struct dma_resv *obj, bool wait_all, bool intr, unsigned long timeout);