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

3 files changed, 75 insertions, 55 deletions

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 4664c2a96c67..d9da766719c8 100644
--- a/drivers/iommu/Kconfig
+++ b/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
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 2d7349a3ee14..041bc1810a86 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/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)
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b7c3d923f3e1..fa0adef32bd6 100644
--- a/drivers/iommu/iova.c
+++ b/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 @@ finish:
         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 @@ error:
                 free_iova_mem(prev);
         return NULL;
 }
+
+MODULE_AUTHOR("Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>");
+MODULE_LICENSE("GPL");