iommu/iova: Tidy up iova_cache_get() failure

Failure handling in iova_cache_get() is a little messy, and we'd like
to add some more to it, so let's tidy up a bit first. By leaving the
hotplug handler until last we can take advantage of kmem_cache_destroy()
being NULL-safe to have a single cleanup label. We can also improve the
error reporting, noting that kmem_cache_create() already screams if it
fails, so that one is redundant.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/ae4a3bda2d6a9b738221553c838d30473bd624e7.1707144953.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index d30e453d0fb4b74a7eb47c77a86b3f11773c0742..cf95001d85c0b0e10b40ead45896cbe873284736 100644 (file)
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -254,26 +254,20 @@ static void free_iova_mem(struct iova *iova)
 
 int iova_cache_get(void)
 {
+       int err = -ENOMEM;
+
        mutex_lock(&iova_cache_mutex);
        if (!iova_cache_users) {
-               int ret;
-
-               ret = cpuhp_setup_state_multi(CPUHP_IOMMU_IOVA_DEAD, "iommu/iova:dead", NULL,
-                                       iova_cpuhp_dead);
-               if (ret) {
-                       mutex_unlock(&iova_cache_mutex);
-                       pr_err("Couldn't register cpuhp handler\n");
-                       return ret;
-               }
+               iova_cache = kmem_cache_create("iommu_iova", sizeof(struct iova), 0,
+                                              SLAB_HWCACHE_ALIGN, NULL);
+               if (!iova_cache)
+                       goto out_err;
 
-               iova_cache = kmem_cache_create(
-                       "iommu_iova", sizeof(struct iova), 0,
-                       SLAB_HWCACHE_ALIGN, NULL);
-               if (!iova_cache) {
-                       cpuhp_remove_multi_state(CPUHP_IOMMU_IOVA_DEAD);
-                       mutex_unlock(&iova_cache_mutex);
-                       pr_err("Couldn't create iova cache\n");
-                       return -ENOMEM;
+               err = cpuhp_setup_state_multi(CPUHP_IOMMU_IOVA_DEAD, "iommu/iova:dead",
+                                             NULL, iova_cpuhp_dead);
+               if (err) {
+                       pr_err("IOVA: Couldn't register cpuhp handler: %pe\n", ERR_PTR(err));
+                       goto out_err;
                }
        }
 
@@ -281,6 +275,11 @@ int iova_cache_get(void)
        mutex_unlock(&iova_cache_mutex);
 
        return 0;
+
+out_err:
+       kmem_cache_destroy(iova_cache);
+       mutex_unlock(&iova_cache_mutex);
+       return err;
 }
 EXPORT_SYMBOL_GPL(iova_cache_get);