Commit 92cedee6 authored by Christian König's avatar Christian König
Browse files

dma-buf: add dma_resv_get_singleton v2 



Add a function to simplify getting a single fence for all the fences in
the dma_resv object.

v2: fix ref leak in error handling

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-3-christian.koenig@amd.com
parent d791aec9

drivers/dma-buf/dma-resv.c

+54 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
 */



#include <linux/dma-resv.h>

#include <linux/dma-fence-array.h>

#include <linux/export.h>

#include <linux/mm.h>

#include <linux/sched/mm.h>
@@ -636,6 +637,59 @@ int dma_resv_get_fences(struct dma_resv *obj, bool write, 
}

EXPORT_SYMBOL_GPL(dma_resv_get_fences);



/**

 * dma_resv_get_singleton - Get a single fence for all the fences

 * @obj: the reservation object

 * @write: true if we should return all fences

 * @fence: the resulting fence

 *

 * Get a single fence representing all the fences inside the resv object.

 * Returns either 0 for success or -ENOMEM.

 *

 * Warning: This can't be used like this when adding the fence back to the resv

 * object since that can lead to stack corruption when finalizing the

 * dma_fence_array.

 *

 * Returns 0 on success and negative error values on failure.

 */

int dma_resv_get_singleton(struct dma_resv *obj, bool write,

			   struct dma_fence **fence)

{

	struct dma_fence_array *array;

	struct dma_fence **fences;

	unsigned count;

	int r;



	r = dma_resv_get_fences(obj, write, &count, &fences);

        if (r)

		return r;



	if (count == 0) {

		*fence = NULL;

		return 0;

	}



	if (count == 1) {

		*fence = fences[0];

		kfree(fences);

		return 0;

	}



	array = dma_fence_array_create(count, fences,

				       dma_fence_context_alloc(1),

				       1, false);

	if (!array) {

		while (count--)

			dma_fence_put(fences[count]);

		kfree(fences);

		return -ENOMEM;

	}



	*fence = &array->base;

	return 0;

}

EXPORT_SYMBOL_GPL(dma_resv_get_singleton);



/**

 * dma_resv_wait_timeout - Wait on reservation's objects

 * shared and/or exclusive fences.

include/linux/dma-resv.h

+2 −0
Original line number Diff line number Diff line
@@ -437,6 +437,8 @@ void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context, 
void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence);

int dma_resv_get_fences(struct dma_resv *obj, bool write,

			unsigned int *num_fences, struct dma_fence ***fences);

int dma_resv_get_singleton(struct dma_resv *obj, bool write,

			   struct dma_fence **fence);

int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);

long dma_resv_wait_timeout(struct dma_resv *obj, bool wait_all, bool intr,

			   unsigned long timeout);