Commit 94eb1e10 authored Jul 12, 2019 by Chris Wilson

dma-buf: Expand reservation_list to fill allocation



Since kmalloc() will round up the allocation to the next slab size or
page, it will normally return a pointer to a memory block bigger than we
asked for. We can query for the actual size of the allocated block using
ksize() and expand our variable size reservation_list to take advantage
of that extra space.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christian König <christian.koenig@amd.com>
Cc: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190712080314.21018-1-chris@chris-wilson.co.uk

parent 913cafbb

drivers/dma-buf/reservation.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -153,7 +153,9 @@ int reservation_object_reserve_shared(struct reservation_object *obj,
		RCU_INIT_POINTER(new->shared[j++], fence);
		}
		new->shared_count = j;
		new->shared_max = max;
		new->shared_max =
		(ksize(new) - offsetof(typeof(*new), shared)) /
		sizeof(*new->shared);

		preempt_disable();
		write_seqcount_begin(&obj->seq);
		@@ -169,7 +171,7 @@ int reservation_object_reserve_shared(struct reservation_object *obj,
		return 0;

		/* Drop the references to the signaled fences */
		for (i = k; i < new->shared_max; ++i) {
		for (i = k; i < max; ++i) {
		struct dma_fence *fence;

		fence = rcu_dereference_protected(new->shared[i],

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