Merge git://git.infradead.org/intel-iommu

Pull IOVA fixes from David Woodhouse:
 "The main fix here is the first one, fixing the over-allocation of
   size-aligned requests.  The other patches simply make the existing
  IOVA code available to users other than the Intel VT-d driver, with no
  functional change.

  I concede the latter really *should* have been submitted during the
  merge window, but since it's basically risk-free and people are
  waiting to build on top of it and it's my fault I didn't get it in, I
  (and they) would be grateful if you'd take it"

* git://git.infradead.org/intel-iommu:
  iommu: Make the iova library a module
  iommu: iova: Export symbols
  iommu: iova: Move iova cache management to the iova library
  iommu/iova: Avoid over-allocating when size-aligned

drivers/iommu/Kconfig

@@ -43,7 +43,7 @@ config IOMMU_IO_PGTABLE_LPAE_SELFTEST
 endmenu
 
 config IOMMU_IOVA
-	bool
+	tristate
 
 config OF_IOMMU
        def_bool y

drivers/iommu/intel-iommu.c

@@ -3215,6 +3215,8 @@ static struct iova *intel_alloc_iova(struct device *dev,
 
 	/* Restrict dma_mask to the width that the iommu can handle */
 	dma_mask = min_t(uint64_t, DOMAIN_MAX_ADDR(domain->gaw), dma_mask);
+	/* Ensure we reserve the whole size-aligned region */
+	nrpages = __roundup_pow_of_two(nrpages);
 
 	if (!dmar_forcedac && dma_mask > DMA_BIT_MASK(32)) {
 		/*
@@ -3711,7 +3713,7 @@ static inline int iommu_devinfo_cache_init(void)
 static int __init iommu_init_mempool(void)
 {
 	int ret;
-	ret = iommu_iova_cache_init();
+	ret = iova_cache_get();
 	if (ret)
 		return ret;
 
@@ -3725,7 +3727,7 @@ static int __init iommu_init_mempool(void)
 
 	kmem_cache_destroy(iommu_domain_cache);
 domain_error:
-	iommu_iova_cache_destroy();
+	iova_cache_put();
 
 	return -ENOMEM;
 }
@@ -3734,7 +3736,7 @@ static void __init iommu_exit_mempool(void)
 {
 	kmem_cache_destroy(iommu_devinfo_cache);
 	kmem_cache_destroy(iommu_domain_cache);
-	iommu_iova_cache_destroy();
+	iova_cache_put();
 }
 
 static void quirk_ioat_snb_local_iommu(struct pci_dev *pdev)

drivers/iommu/iova.c

@@ -18,42 +18,9 @@
  */
 
 #include <linux/iova.h>
+#include <linux/module.h>
 #include <linux/slab.h>
 
-static struct kmem_cache *iommu_iova_cache;
-
-int iommu_iova_cache_init(void)
-{
-	int ret = 0;
-
-	iommu_iova_cache = kmem_cache_create("iommu_iova",
-					 sizeof(struct iova),
-					 0,
-					 SLAB_HWCACHE_ALIGN,
-					 NULL);
-	if (!iommu_iova_cache) {
-		pr_err("Couldn't create iova cache\n");
-		ret = -ENOMEM;
-	}
-
-	return ret;
-}
-
-void iommu_iova_cache_destroy(void)
-{
-	kmem_cache_destroy(iommu_iova_cache);
-}
-
-struct iova *alloc_iova_mem(void)
-{
-	return kmem_cache_alloc(iommu_iova_cache, GFP_ATOMIC);
-}
-
-void free_iova_mem(struct iova *iova)
-{
-	kmem_cache_free(iommu_iova_cache, iova);
-}
-
 void
 init_iova_domain(struct iova_domain *iovad, unsigned long granule,
 	unsigned long start_pfn, unsigned long pfn_32bit)
@@ -72,6 +39,7 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
 	iovad->start_pfn = start_pfn;
 	iovad->dma_32bit_pfn = pfn_32bit;
 }
+EXPORT_SYMBOL_GPL(init_iova_domain);
 
 static struct rb_node *
 __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
@@ -120,19 +88,14 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
 	}
 }
 
-/* Computes the padding size required, to make the
- * the start address naturally aligned on its size
+/*
+ * Computes the padding size required, to make the start address
+ * naturally aligned on the power-of-two order of its size
  */
-static int
-iova_get_pad_size(int size, unsigned int limit_pfn)
+static unsigned int
+iova_get_pad_size(unsigned int size, unsigned int limit_pfn)
 {
-	unsigned int pad_size = 0;
-	unsigned int order = ilog2(size);
-
-	if (order)
-		pad_size = (limit_pfn + 1) % (1 << order);
-
-	return pad_size;
+	return (limit_pfn + 1 - size) & (__roundup_pow_of_two(size) - 1);
 }
 
 static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
@@ -242,6 +205,57 @@ iova_insert_rbtree(struct rb_root *root, struct iova *iova)
 	rb_insert_color(&iova->node, root);
 }
 
+static struct kmem_cache *iova_cache;
+static unsigned int iova_cache_users;
+static DEFINE_MUTEX(iova_cache_mutex);
+
+struct iova *alloc_iova_mem(void)
+{
+	return kmem_cache_alloc(iova_cache, GFP_ATOMIC);
+}
+EXPORT_SYMBOL(alloc_iova_mem);
+
+void free_iova_mem(struct iova *iova)
+{
+	kmem_cache_free(iova_cache, iova);
+}
+EXPORT_SYMBOL(free_iova_mem);
+
+int iova_cache_get(void)
+{
+	mutex_lock(&iova_cache_mutex);
+	if (!iova_cache_users) {
+		iova_cache = kmem_cache_create(
+			"iommu_iova", sizeof(struct iova), 0,
+			SLAB_HWCACHE_ALIGN, NULL);
+		if (!iova_cache) {
+			mutex_unlock(&iova_cache_mutex);
+			printk(KERN_ERR "Couldn't create iova cache\n");
+			return -ENOMEM;
+		}
+	}
+
+	iova_cache_users++;
+	mutex_unlock(&iova_cache_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iova_cache_get);
+
+void iova_cache_put(void)
+{
+	mutex_lock(&iova_cache_mutex);
+	if (WARN_ON(!iova_cache_users)) {
+		mutex_unlock(&iova_cache_mutex);
+		return;
+	}
+	iova_cache_users--;
+	if (!iova_cache_users)
+		kmem_cache_destroy(iova_cache);
+	mutex_unlock(&iova_cache_mutex);
+}
+EXPORT_SYMBOL_GPL(iova_cache_put);
+
 /**
  * alloc_iova - allocates an iova
  * @iovad: - iova domain in question
@@ -265,12 +279,6 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,
 	if (!new_iova)
 		return NULL;
 
-	/* If size aligned is set then round the size to
-	 * to next power of two.
-	 */
-	if (size_aligned)
-		size = __roundup_pow_of_two(size);
-
 	ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn,
 			new_iova, size_aligned);
 
@@ -281,6 +289,7 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,
 
 	return new_iova;
 }
+EXPORT_SYMBOL_GPL(alloc_iova);
 
 /**
  * find_iova - find's an iova for a given pfn
@@ -321,6 +330,7 @@ struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(find_iova);
 
 /**
  * __free_iova - frees the given iova
@@ -339,6 +349,7 @@ __free_iova(struct iova_domain *iovad, struct iova *iova)
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 	free_iova_mem(iova);
 }
+EXPORT_SYMBOL_GPL(__free_iova);
 
 /**
  * free_iova - finds and frees the iova for a given pfn
@@ -356,6 +367,7 @@ free_iova(struct iova_domain *iovad, unsigned long pfn)
 		__free_iova(iovad, iova);
 
 }
+EXPORT_SYMBOL_GPL(free_iova);
 
 /**
  * put_iova_domain - destroys the iova doamin
@@ -378,6 +390,7 @@ void put_iova_domain(struct iova_domain *iovad)
 	}
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 }
+EXPORT_SYMBOL_GPL(put_iova_domain);
 
 static int
 __is_range_overlap(struct rb_node *node,
@@ -467,6 +480,7 @@ reserve_iova(struct iova_domain *iovad,
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 	return iova;
 }
+EXPORT_SYMBOL_GPL(reserve_iova);
 
 /**
  * copy_reserved_iova - copies the reserved between domains
@@ -493,6 +507,7 @@ copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
 	}
 	spin_unlock_irqrestore(&from->iova_rbtree_lock, flags);
 }
+EXPORT_SYMBOL_GPL(copy_reserved_iova);
 
 struct iova *
 split_and_remove_iova(struct iova_domain *iovad, struct iova *iova,
@@ -534,3 +549,6 @@ split_and_remove_iova(struct iova_domain *iovad, struct iova *iova,
 		free_iova_mem(prev);
 	return NULL;
 }
+
+MODULE_AUTHOR("Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>");
+MODULE_LICENSE("GPL");

include/linux/iova.h

@@ -68,8 +68,8 @@ static inline unsigned long iova_pfn(struct iova_domain *iovad, dma_addr_t iova)
 	return iova >> iova_shift(iovad);
 }
 
-int iommu_iova_cache_init(void);
-void iommu_iova_cache_destroy(void);
+int iova_cache_get(void);
+void iova_cache_put(void);
 
 struct iova *alloc_iova_mem(void);
 void free_iova_mem(struct iova *iova);