iommu: iova: Move iova cache management to the iova library

This is necessary to separate intel-iommu from the iova library.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

2 files changed, 52 insertions, 37 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 92101597cede..2d5cf39e1053 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3743,7 +3743,7 @@ 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;
 
@@ -3757,7 +3757,7 @@ static int __init iommu_init_mempool(void)
 
         kmem_cache_destroy(iommu_domain_cache);
 domain_error:
-        iommu_iova_cache_destroy();
+        iova_cache_put();
 
         return -ENOMEM;
 }
@@ -3766,7 +3766,7 @@ 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 29f2efcf668e..ed95f7a0fad3 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -20,40 +20,6 @@
 #include <linux/iova.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)
@@ -237,6 +203,55 @@ 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;
+}
+
+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);
+}
+
 /**
  * alloc_iova - allocates an iova
  * @iovad: - iova domain in question