IB/core: Restore I/O MMU, s390 and powerpc support

Avoid that the following error message is reported on the console
while loading an RDMA driver with I/O MMU support enabled:

DMAR: Allocating domain for mlx5_0 failed

Ensure that DMA mapping operations that use to_pci_dev() to
access to struct pci_dev see the correct PCI device. E.g. the s390
and powerpc DMA mapping operations use to_pci_dev() even with I/O
MMU support disabled.

This patch preserves the following changes of the DMA mapping updates
patch series:
- Introduction of dma_virt_ops.
- Removal of ib_device.dma_ops.
- Removal of struct ib_dma_mapping_ops.
- Removal of an if-statement from each ib_dma_*() operation.
- IB HW drivers no longer set dma_device directly.

Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reported-by: Parav Pandit <parav@mellanox.com>
Fixes: commit 99db9494035f ("IB/core: Remove ib_device.dma_device")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: parav@mellanox.com
Tested-by: parav@mellanox.com
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

2 files changed, 37 insertions, 19 deletions

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 593d2ce6ec7c..addf869045cc 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -336,12 +336,26 @@ int ib_register_device(struct ib_device *device,
 	struct device *parent = device->dev.parent;
 
 	WARN_ON_ONCE(!parent);
-	if (!device->dev.dma_ops)
-		device->dev.dma_ops = parent->dma_ops;
-	if (!device->dev.dma_mask)
-		device->dev.dma_mask = parent->dma_mask;
-	if (!device->dev.coherent_dma_mask)
-		device->dev.coherent_dma_mask = parent->coherent_dma_mask;
+	WARN_ON_ONCE(device->dma_device);
+	if (device->dev.dma_ops) {
+		/*
+		 * The caller provided custom DMA operations. Copy the
+		 * DMA-related fields that are used by e.g. dma_alloc_coherent()
+		 * into device->dev.
+		 */
+		device->dma_device = &device->dev;
+		if (!device->dev.dma_mask)
+			device->dev.dma_mask = parent->dma_mask;
+		if (!device->dev.coherent_dma_mask)
+			device->dev.coherent_dma_mask =
+				parent->coherent_dma_mask;
+	} else {
+		/*
+		 * The caller did not provide custom DMA operations. Use the
+		 * DMA mapping operations of the parent device.
+		 */
+		device->dma_device = parent;
+	}
 
 	mutex_lock(&device_mutex);
 
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 0f1813c13687..99e4423eb2b8 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1863,6 +1863,9 @@ struct ib_port_immutable {
 };
 
 struct ib_device {
+	/* Do not access @dma_device directly from ULP nor from HW drivers. */
+	struct device                *dma_device;
+
 	char                          name[IB_DEVICE_NAME_MAX];
 
 	struct list_head              event_handler_list;
@@ -3007,7 +3010,7 @@ static inline int ib_req_ncomp_notif(struct ib_cq *cq, int wc_cnt)
  */
 static inline int ib_dma_mapping_error(struct ib_device *dev, u64 dma_addr)
 {
-	return dma_mapping_error(&dev->dev, dma_addr);
+	return dma_mapping_error(dev->dma_device, dma_addr);
 }
 
 /**
@@ -3021,7 +3024,7 @@ static inline u64 ib_dma_map_single(struct ib_device *dev,
 				    void *cpu_addr, size_t size,
 				    enum dma_data_direction direction)
 {
-	return dma_map_single(&dev->dev, cpu_addr, size, direction);
+	return dma_map_single(dev->dma_device, cpu_addr, size, direction);
 }
 
 /**
@@ -3035,7 +3038,7 @@ static inline void ib_dma_unmap_single(struct ib_device *dev,
 				       u64 addr, size_t size,
 				       enum dma_data_direction direction)
 {
-	dma_unmap_single(&dev->dev, addr, size, direction);
+	dma_unmap_single(dev->dma_device, addr, size, direction);
 }
 
 /**
@@ -3052,7 +3055,7 @@ static inline u64 ib_dma_map_page(struct ib_device *dev,
 				  size_t size,
 					 enum dma_data_direction direction)
 {
-	return dma_map_page(&dev->dev, page, offset, size, direction);
+	return dma_map_page(dev->dma_device, page, offset, size, direction);
 }
 
 /**
@@ -3066,7 +3069,7 @@ static inline void ib_dma_unmap_page(struct ib_device *dev,
 				     u64 addr, size_t size,
 				     enum dma_data_direction direction)
 {
-	dma_unmap_page(&dev->dev, addr, size, direction);
+	dma_unmap_page(dev->dma_device, addr, size, direction);
 }
 
 /**
@@ -3080,7 +3083,7 @@ static inline int ib_dma_map_sg(struct ib_device *dev,
 				struct scatterlist *sg, int nents,
 				enum dma_data_direction direction)
 {
-	return dma_map_sg(&dev->dev, sg, nents, direction);
+	return dma_map_sg(dev->dma_device, sg, nents, direction);
 }
 
 /**
@@ -3094,7 +3097,7 @@ static inline void ib_dma_unmap_sg(struct ib_device *dev,
 				   struct scatterlist *sg, int nents,
 				   enum dma_data_direction direction)
 {
-	dma_unmap_sg(&dev->dev, sg, nents, direction);
+	dma_unmap_sg(dev->dma_device, sg, nents, direction);
 }
 
 static inline int ib_dma_map_sg_attrs(struct ib_device *dev,
@@ -3102,7 +3105,8 @@ static inline int ib_dma_map_sg_attrs(struct ib_device *dev,
 				      enum dma_data_direction direction,
 				      unsigned long dma_attrs)
 {
-	return dma_map_sg_attrs(&dev->dev, sg, nents, direction, dma_attrs);
+	return dma_map_sg_attrs(dev->dma_device, sg, nents, direction,
+				dma_attrs);
 }
 
 static inline void ib_dma_unmap_sg_attrs(struct ib_device *dev,
@@ -3110,7 +3114,7 @@ static inline void ib_dma_unmap_sg_attrs(struct ib_device *dev,
 					 enum dma_data_direction direction,
 					 unsigned long dma_attrs)
 {
-	dma_unmap_sg_attrs(&dev->dev, sg, nents, direction, dma_attrs);
+	dma_unmap_sg_attrs(dev->dma_device, sg, nents, direction, dma_attrs);
 }
 /**
  * ib_sg_dma_address - Return the DMA address from a scatter/gather entry
@@ -3152,7 +3156,7 @@ static inline void ib_dma_sync_single_for_cpu(struct ib_device *dev,
 					      size_t size,
 					      enum dma_data_direction dir)
 {
-	dma_sync_single_for_cpu(&dev->dev, addr, size, dir);
+	dma_sync_single_for_cpu(dev->dma_device, addr, size, dir);
 }
 
 /**
@@ -3167,7 +3171,7 @@ static inline void ib_dma_sync_single_for_device(struct ib_device *dev,
 						 size_t size,
 						 enum dma_data_direction dir)
 {
-	dma_sync_single_for_device(&dev->dev, addr, size, dir);
+	dma_sync_single_for_device(dev->dma_device, addr, size, dir);
 }
 
 /**
@@ -3182,7 +3186,7 @@ static inline void *ib_dma_alloc_coherent(struct ib_device *dev,
 					   dma_addr_t *dma_handle,
 					   gfp_t flag)
 {
-	return dma_alloc_coherent(&dev->dev, size, dma_handle, flag);
+	return dma_alloc_coherent(dev->dma_device, size, dma_handle, flag);
 }
 
 /**
@@ -3196,7 +3200,7 @@ static inline void ib_dma_free_coherent(struct ib_device *dev,
 					size_t size, void *cpu_addr,
 					dma_addr_t dma_handle)
 {
-	dma_free_coherent(&dev->dev, size, cpu_addr, dma_handle);
+	dma_free_coherent(dev->dma_device, size, cpu_addr, dma_handle);
 }
 
 /**