linux-kernel - [PATCH v7 07/10] iommu/dma-reserved-iommu: delete bindings in iommu_free_reserved_iova

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Date:	Tue, 19 Apr 2016 16:56:31 +0000
From:	Eric Auger <eric.auger@...aro.org>
To:	eric.auger@...com, eric.auger@...aro.org, robin.murphy@....com,
	alex.williamson@...hat.com, will.deacon@....com, joro@...tes.org,
	tglx@...utronix.de, jason@...edaemon.net, marc.zyngier@....com,
	christoffer.dall@...aro.org, linux-arm-kernel@...ts.infradead.org
Cc:	patches@...aro.org, linux-kernel@...r.kernel.org,
	Bharat.Bhushan@...escale.com, pranav.sawargaonkar@...il.com,
	p.fedin@...sung.com, iommu@...ts.linux-foundation.org,
	Jean-Philippe.Brucker@....com, julien.grall@....com
Subject: [PATCH v7 07/10] iommu/dma-reserved-iommu: delete bindings in iommu_free_reserved_iova_domain

Now reserved bindings can exist, destroy them when destroying
the reserved iova domain. iommu_map is not supposed to be atomic,
hence the extra complexity in the locking.

Signed-off-by: Eric Auger <eric.auger@...aro.org>

---
v6 -> v7:
- remove [PATCH v6 7/7] dma-reserved-iommu: iommu_unmap_reserved and
  destroy the bindings in iommu_free_reserved_iova_domain

v5 -> v6:
- use spin_lock instead of mutex

v3 -> v4:
- previously "iommu/arm-smmu: relinquish reserved resources on
  domain deletion"
---
 drivers/iommu/dma-reserved-iommu.c | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/dma-reserved-iommu.c b/drivers/iommu/dma-reserved-iommu.c
index 426d339..2522235 100644
--- a/drivers/iommu/dma-reserved-iommu.c
+++ b/drivers/iommu/dma-reserved-iommu.c
@@ -157,14 +157,36 @@ void iommu_free_reserved_iova_domain(struct iommu_domain *domain)
 	unsigned long flags;
 	int ret = 0;
 
-	spin_lock_irqsave(&domain->reserved_lock, flags);
-
-	rid = (struct reserved_iova_domain *)domain->reserved_iova_cookie;
-	if (!rid) {
-		ret = -EINVAL;
-		goto unlock;
+	while (1) {
+		struct iommu_reserved_binding *b;
+		struct rb_node *node;
+		dma_addr_t iova;
+		size_t size;
+
+		spin_lock_irqsave(&domain->reserved_lock, flags);
+
+		rid = (struct reserved_iova_domain *)
+				domain->reserved_iova_cookie;
+		if (!rid) {
+			ret = -EINVAL;
+			goto unlock;
+		}
+
+		node = rb_first(&domain->reserved_binding_list);
+		if (!node)
+			break;
+		b = rb_entry(node, struct iommu_reserved_binding, node);
+
+		iova = b->iova;
+		size = b->size;
+
+		while (!kref_put(&b->kref, reserved_binding_release))
+			;
+		spin_unlock_irqrestore(&domain->reserved_lock, flags);
+		iommu_unmap(domain, iova, size);
 	}
 
+	domain->reserved_binding_list = RB_ROOT;
 	domain->reserved_iova_cookie = NULL;
 unlock:
 	spin_unlock_irqrestore(&domain->reserved_lock, flags);
-- 
1.9.1