As the set of shared fences is not being changed during reallocation of the reservation list, we can skip updating the write_seqlock. Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Christian König <christian.koenig@xxxxxxx> --- drivers/dma-buf/reservation.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index 80ecc1283d15..c71b85c8c159 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -157,15 +157,15 @@ int reservation_object_reserve_shared(struct reservation_object *obj, (ksize(new) - offsetof(typeof(*new), shared)) / sizeof(*new->shared); - preempt_disable(); - write_seqcount_begin(&obj->seq); /* - * RCU_INIT_POINTER can be used here, - * seqcount provides the necessary barriers + * We are not changing the effective set of fences here so can + * merely update the pointer to the new array; both existing + * readers and new readers will see exactly the same set of + * active (unsignaled) shared fences. Individual fences and the + * old array are protected by RCU and so will not vanish under + * the gaze of the rcu_read_lock() readers. */ - RCU_INIT_POINTER(obj->fence, new); - write_seqcount_end(&obj->seq); - preempt_enable(); + rcu_assign_pointer(obj->fence, new); if (!old) return 0; -- 2.22.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
