1 files changed, 18 insertions, 22 deletions

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 8c02d2283d64..53f7cfe9b0a9 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -17,6 +17,7 @@
 #include <linux/iova.h>
 #include <linux/irq.h>
 #include <linux/mm.h>
+#include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/scatterlist.h>
 #include <linux/vmalloc.h>
@@ -41,7 +42,6 @@ struct iommu_dma_cookie {
 		dma_addr_t		msi_iova;
 	};
 	struct list_head		msi_page_list;
-	spinlock_t			msi_lock;
 
 	/* Domain for flush queue callback; NULL if flush queue not in use */
 	struct iommu_domain		*fq_domain;
@@ -60,7 +60,6 @@ static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type)
 
 	cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
 	if (cookie) {
-		spin_lock_init(&cookie->msi_lock);
 		INIT_LIST_HEAD(&cookie->msi_page_list);
 		cookie->type = type;
 	}
@@ -180,15 +179,15 @@ static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie,
 	start -= iova_offset(iovad, start);
 	num_pages = iova_align(iovad, end - start) >> iova_shift(iovad);
 
-	msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL);
-	if (!msi_page)
-		return -ENOMEM;
-
 	for (i = 0; i < num_pages; i++) {
-		msi_page[i].phys = start;
-		msi_page[i].iova = start;
-		INIT_LIST_HEAD(&msi_page[i].list);
-		list_add(&msi_page[i].list, &cookie->msi_page_list);
+		msi_page = kmalloc(sizeof(*msi_page), GFP_KERNEL);
+		if (!msi_page)
+			return -ENOMEM;
+
+		msi_page->phys = start;
+		msi_page->iova = start;
+		INIT_LIST_HEAD(&msi_page->list);
+		list_add(&msi_page->list, &cookie->msi_page_list);
 		start += iovad->granule;
 	}
 
@@ -229,8 +228,8 @@ resv_iova:
 		start = window->res->end - window->offset + 1;
 		/* If window is last entry */
 		if (window->node.next == &bridge->dma_ranges &&
-		    end != ~(dma_addr_t)0) {
-			end = ~(dma_addr_t)0;
+		    end != ~(phys_addr_t)0) {
+			end = ~(phys_addr_t)0;
 			goto resv_iova;
 		}
 	}
@@ -877,7 +876,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
 		if (msi_page->phys == msi_addr)
 			return msi_page;
 
-	msi_page = kzalloc(sizeof(*msi_page), GFP_ATOMIC);
+	msi_page = kzalloc(sizeof(*msi_page), GFP_KERNEL);
 	if (!msi_page)
 		return NULL;
 
@@ -900,25 +899,22 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
 {
 	struct device *dev = msi_desc_to_dev(desc);
 	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
-	struct iommu_dma_cookie *cookie;
 	struct iommu_dma_msi_page *msi_page;
-	unsigned long flags;
+	static DEFINE_MUTEX(msi_prepare_lock); /* see below */
 
 	if (!domain || !domain->iova_cookie) {
 		desc->iommu_cookie = NULL;
 		return 0;
 	}
 
-	cookie = domain->iova_cookie;
-
 	/*
-	 * We disable IRQs to rule out a possible inversion against
-	 * irq_desc_lock if, say, someone tries to retarget the affinity
-	 * of an MSI from within an IPI handler.
+	 * In fact the whole prepare operation should already be serialised by
+	 * irq_domain_mutex further up the callchain, but that's pretty subtle
+	 * on its own, so consider this locking as failsafe documentation...
 	 */
-	spin_lock_irqsave(&cookie->msi_lock, flags);
+	mutex_lock(&msi_prepare_lock);
 	msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain);
-	spin_unlock_irqrestore(&cookie->msi_lock, flags);
+	mutex_unlock(&msi_prepare_lock);
 
 	msi_desc_set_iommu_cookie(desc, msi_page);