iommu/amd: Free already flushed ring-buffer entries before full-check

To benefit from IOTLB flushes on other CPUs we have to free
the already flushed IOVAs from the ring-buffer before we do
the queue_ring_full() check.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 95ee360..c618c26 100644 (file)
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1911,14 +1911,20 @@ static void queue_add(struct dma_ops_domain *dom,
        spin_lock_irqsave(&queue->lock, flags);
 
        /*
+        * First remove the enries from the ring-buffer that are already
+        * flushed to make the below queue_ring_full() check less likely
+        */
+       queue_ring_free_flushed(dom, queue);
+
+       /*
         * When ring-queue is full, flush the entries from the IOTLB so
         * that we can free all entries with queue_ring_free_flushed()
         * below.
         */
-       if (queue_ring_full(queue))
+       if (queue_ring_full(queue)) {
                dma_ops_domain_flush_tlb(dom);
-
-       queue_ring_free_flushed(dom, queue);
+               queue_ring_free_flushed(dom, queue);
+       }
 
        idx = queue_ring_add(queue);