RDMA: Explicitly pass in the dma_device to ib_register_device

The code in setup_dma_device has become rather convoluted, move all of
this to the drivers. Drives now pass in a DMA capable struct device which
will be used to setup DMA, or drivers must fully configure the ibdev for
DMA and pass in NULL.

Other than setting the masks in rvt all drivers were doing this already
anyhow.

mthca, mlx4 and mlx5 were already setting up maximum DMA segment size for
DMA based on their hardweare limits in:
__mthca_init_one()
  dma_set_max_seg_size (1G)

__mlx4_init_one()
  dma_set_max_seg_size (1G)

mlx5_pci_init()
  set_dma_caps()
    dma_set_max_seg_size (2G)

Other non software drivers (except usnic) were extended to UINT_MAX [1, 2]
instead of 2G as was before.

[1] https://lore.kernel.org/linux-rdma/20200924114940.GE9475@nvidia.com/
[2] https://lore.kernel.org/linux-rdma/20200924114940.GE9475@nvidia.com/

Link: https://lore.kernel.org/r/20201008082752.275846-1-leon@kernel.org
Link: https://lore.kernel.org/r/6b2ed339933d066622d5715903870676d8cc523a.1602590106.git.mchehab+huawei@kernel.org
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

1 files changed, 22 insertions, 53 deletions

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index dab1f9d65880..a3b1fc84cdca 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -1177,58 +1177,23 @@ out:
 	return ret;
 }
 
-static void setup_dma_device(struct ib_device *device)
+static void setup_dma_device(struct ib_device *device,
+			     struct device *dma_device)
 {
-	struct device *parent = device->dev.parent;
-
-	WARN_ON_ONCE(device->dma_device);
-
-#ifdef CONFIG_DMA_OPS
-	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) {
-			if (parent)
-				device->dev.dma_mask = parent->dma_mask;
-			else
-				WARN_ON_ONCE(true);
-		}
-		if (!device->dev.coherent_dma_mask) {
-			if (parent)
-				device->dev.coherent_dma_mask =
-					parent->coherent_dma_mask;
-			else
-				WARN_ON_ONCE(true);
-		}
-	} else
-#endif /* CONFIG_DMA_OPS */
-	{
-		/*
-		 * The caller did not provide custom DMA operations. Use the
-		 * DMA mapping operations of the parent device.
-		 */
-		WARN_ON_ONCE(!parent);
-		device->dma_device = parent;
-	}
-
-	if (!device->dev.dma_parms) {
-		if (parent) {
-			/*
-			 * The caller did not provide DMA parameters, so
-			 * 'parent' probably represents a PCI device. The PCI
-			 * core sets the maximum segment size to 64
-			 * KB. Increase this parameter to 2 GB.
-			 */
-			device->dev.dma_parms = parent->dma_parms;
-			dma_set_max_seg_size(device->dma_device, SZ_2G);
-		} else {
-			WARN_ON_ONCE(true);
-		}
+	/*
+	 * If the caller does not provide a DMA capable device then the IB
+	 * device will be used. In this case the caller should fully setup the
+	 * ibdev for DMA. This usually means using dma_virt_ops.
+	 */
+#ifdef CONFIG_DMA_VIRT_OPS
+	if (!dma_device) {
+		device->dev.dma_ops = &dma_virt_ops;
+		dma_device = &device->dev;
 	}
+#endif
+	WARN_ON(!dma_device);
+	device->dma_device = dma_device;
+	WARN_ON(!device->dma_device->dma_parms);
 }
 
 /*
@@ -1241,7 +1206,6 @@ static int setup_device(struct ib_device *device)
 	struct ib_udata uhw = {.outlen = 0, .inlen = 0};
 	int ret;
 
-	setup_dma_device(device);
 	ib_device_check_mandatory(device);
 
 	ret = setup_port_data(device);
@@ -1354,7 +1318,10 @@ static void prevent_dealloc_device(struct ib_device *ib_dev)
  * ib_register_device - Register an IB device with IB core
  * @device: Device to register
  * @name: unique string device name. This may include a '%' which will
- * cause a unique index to be added to the passed device name.
+ * 	  cause a unique index to be added to the passed device name.
+ * @dma_device: pointer to a DMA-capable device. If %NULL, then the IB
+ *	        device will be used. In this case the caller should fully
+ *		setup the ibdev for DMA. This usually means using dma_virt_ops.
  *
  * Low-level drivers use ib_register_device() to register their
  * devices with the IB core.  All registered clients will receive a
@@ -1365,7 +1332,8 @@ static void prevent_dealloc_device(struct ib_device *ib_dev)
  * asynchronously then the device pointer may become freed as soon as this
  * function returns.
  */
-int ib_register_device(struct ib_device *device, const char *name)
+int ib_register_device(struct ib_device *device, const char *name,
+		       struct device *dma_device)
 {
 	int ret;
 
@@ -1373,6 +1341,7 @@ int ib_register_device(struct ib_device *device, const char *name)
 	if (ret)
 		return ret;
 
+	setup_dma_device(device, dma_device);
 	ret = setup_device(device);
 	if (ret)
 		return ret;