iova: Add CPU hotplug handler to flush rcaches

Like the Intel IOMMU driver already does, flush the per-IOVA domain
CPU rcache when a CPU goes offline - there's no point in keeping it.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1616675401-151997-2-git-send-email-john.garry@huawei.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 471c48d..8542059 100644 (file)
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -25,6 +25,17 @@ static void init_iova_rcaches(struct iova_domain *iovad);
 static void free_iova_rcaches(struct iova_domain *iovad);
 static void fq_destroy_all_entries(struct iova_domain *iovad);
 static void fq_flush_timeout(struct timer_list *t);
+
+static int iova_cpuhp_dead(unsigned int cpu, struct hlist_node *node)
+{
+       struct iova_domain *iovad;
+
+       iovad = hlist_entry_safe(node, struct iova_domain, cpuhp_dead);
+
+       free_cpu_cached_iovas(cpu, iovad);
+       return 0;
+}
+
 static void free_global_cached_iovas(struct iova_domain *iovad);
 
 static struct iova *to_iova(struct rb_node *node)
@@ -56,6 +67,7 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
        iovad->anchor.pfn_lo = iovad->anchor.pfn_hi = IOVA_ANCHOR;
        rb_link_node(&iovad->anchor.node, NULL, &iovad->rbroot.rb_node);
        rb_insert_color(&iovad->anchor.node, &iovad->rbroot);
+       cpuhp_state_add_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD, &iovad->cpuhp_dead);
        init_iova_rcaches(iovad);
 }
 EXPORT_SYMBOL_GPL(init_iova_domain);
@@ -299,10 +311,21 @@ int iova_cache_get(void)
 {
        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) {
+                       cpuhp_remove_multi_state(CPUHP_IOMMU_IOVA_DEAD);
                        mutex_unlock(&iova_cache_mutex);
                        pr_err("Couldn't create iova cache\n");
                        return -ENOMEM;
@@ -324,8 +347,10 @@ void iova_cache_put(void)
                return;
        }
        iova_cache_users--;
-       if (!iova_cache_users)
+       if (!iova_cache_users) {
+               cpuhp_remove_multi_state(CPUHP_IOMMU_IOVA_DEAD);
                kmem_cache_destroy(iova_cache);
+       }
        mutex_unlock(&iova_cache_mutex);
 }
 EXPORT_SYMBOL_GPL(iova_cache_put);
@@ -648,6 +673,9 @@ void put_iova_domain(struct iova_domain *iovad)
 {
        struct iova *iova, *tmp;
 
+       cpuhp_state_remove_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD,
+                                           &iovad->cpuhp_dead);
+
        free_iova_flush_queue(iovad);
        free_iova_rcaches(iovad);
        rbtree_postorder_for_each_entry_safe(iova, tmp, &iovad->rbroot, node)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index f14adb8..cedac99 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -58,6 +58,7 @@ enum cpuhp_state {
        CPUHP_NET_DEV_DEAD,
        CPUHP_PCI_XGENE_DEAD,
        CPUHP_IOMMU_INTEL_DEAD,
+       CPUHP_IOMMU_IOVA_DEAD,
        CPUHP_LUSTRE_CFS_DEAD,
        CPUHP_AP_ARM_CACHE_B15_RAC_DEAD,
        CPUHP_PADATA_DEAD,

diff --git a/include/linux/iova.h b/include/linux/iova.h
index c834c01..4be6c0a 100644 (file)
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -95,6 +95,7 @@ struct iova_domain {
                                                   flush-queues */
        atomic_t fq_timer_on;                   /* 1 when timer is active, 0
                                                   when not */
+       struct hlist_node       cpuhp_dead;
 };
 
 static inline unsigned long iova_size(struct iova *iova)