1 files changed, 26 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 1b2a174e7c59..86ae364900d6 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -924,6 +924,13 @@ static void restore_default_window(struct pci_dev *dev,
         __restore_default_window(pci_dev_to_eeh_dev(dev), ddw_restore_token);
 }
 
+struct failed_ddw_pdn {
+        struct device_node *pdn;
+        struct list_head list;
+};
+
+static LIST_HEAD(failed_ddw_pdn_list);
+
 /*
  * If the PE supports dynamic dma windows, and there is space for a table
  * that can map all pages in a linear offset, then setup such a table,
@@ -951,6 +958,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
         struct dynamic_dma_window_prop *ddwprop;
         const void *dma_window = NULL;
         unsigned long liobn, offset, size;
+        struct failed_ddw_pdn *fpdn;
 
         mutex_lock(&direct_window_init_mutex);
 
@@ -959,6 +967,18 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
                 goto out_unlock;
 
         /*
+         * If we already went through this for a previous function of
+         * the same device and failed, we don't want to muck with the
+         * DMA window again, as it will race with in-flight operations
+         * and can lead to EEHs. The above mutex protects access to the
+         * list.
+         */
+        list_for_each_entry(fpdn, &failed_ddw_pdn_list, list) {
+                if (!strcmp(fpdn->pdn->full_name, pdn->full_name))
+                        goto out_unlock;
+        }
+
+        /*
          * the ibm,ddw-applicable property holds the tokens for:
          * ibm,query-pe-dma-window
          * ibm,create-pe-dma-window
@@ -1114,6 +1134,12 @@ out_restore_window:
         if (ddw_restore_token)
                 restore_default_window(dev, ddw_restore_token);
 
+        fpdn = kzalloc(sizeof(*fpdn), GFP_KERNEL);
+        if (!fpdn)
+                goto out_unlock;
+        fpdn->pdn = pdn;
+        list_add(&fpdn->list, &failed_ddw_pdn_list);
+
 out_unlock:
         mutex_unlock(&direct_window_init_mutex);
         return dma_addr;