X-Git-Url: http://git.samba.org/sfrench/?a=blobdiff_plain;f=drivers%2Fiommu%2Fiova.c;h=9e8bc802ac053daf6b2310a00c5074e9548c9082;hb=78e709522d2c012cb0daad2e668506637bffb7c2;hp=b6cf5f16123bdb678548ed2f1fb077efd467a300;hpb=15517c724c6e89ed854191028958a43274e3c366;p=sfrench%2Fcifs-2.6.git

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b6cf5f16123b..9e8bc802ac05 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -121,8 +121,6 @@ int init_iova_flush_queue(struct iova_domain *iovad,
 		spin_lock_init(&fq->lock);
 	}
 
-	smp_wmb();
-
 	iovad->fq = queue;
 
 	timer_setup(&iovad->fq_timer, fq_flush_timeout, 0);
@@ -521,6 +519,7 @@ retry:
 
 	return new_iova->pfn_lo;
 }
+EXPORT_SYMBOL_GPL(alloc_iova_fast);
 
 /**
  * free_iova_fast - free iova pfn range into rcache
@@ -538,6 +537,7 @@ free_iova_fast(struct iova_domain *iovad, unsigned long pfn, unsigned long size)
 
 	free_iova(iovad, pfn);
 }
+EXPORT_SYMBOL_GPL(free_iova_fast);
 
 #define fq_ring_for_each(i, fq) \
 	for ((i) = (fq)->head; (i) != (fq)->tail; (i) = ((i) + 1) % IOVA_FQ_SIZE)
@@ -633,10 +633,20 @@ void queue_iova(struct iova_domain *iovad,
 		unsigned long pfn, unsigned long pages,
 		unsigned long data)
 {
-	struct iova_fq *fq = raw_cpu_ptr(iovad->fq);
+	struct iova_fq *fq;
 	unsigned long flags;
 	unsigned idx;
 
+	/*
+	 * Order against the IOMMU driver's pagetable update from unmapping
+	 * @pte, to guarantee that iova_domain_flush() observes that if called
+	 * from a different CPU before we release the lock below. Full barrier
+	 * so it also pairs with iommu_dma_init_fq() to avoid seeing partially
+	 * written fq state here.
+	 */
+	smp_mb();
+
+	fq = raw_cpu_ptr(iovad->fq);
 	spin_lock_irqsave(&fq->lock, flags);
 
 	/*