[PATCH rdma-next 11/13] RDMA/core: Make device names unique per net namespace

[Jiri Pirko <jiri@resnulli.us>]

From: Jiri Pirko <jiri@nvidia.com>

Use rdma_dev_access_netns() to scope RDMA device name lookup and "%d" name
allocation to the relevant net namespace. Keep shared mode and
CONFIG_NET_NS=n behaviour system-wide.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
 drivers/infiniband/core/device.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 3ccf4731154a..cffb0de1c001 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -129,7 +129,7 @@ static DECLARE_RWSEM(rdma_nets_rwsem);
 bool ib_devices_shared_netns = true;
 module_param_named(netns_mode, ib_devices_shared_netns, bool, 0444);
 MODULE_PARM_DESC(netns_mode,
-		 "Share device among net namespaces; default=1 (shared)");
+		 "Share device among net namespaces; default=1 (shared). In exclusive mode device names are unique per net namespace");
 /**
  * rdma_dev_access_netns() - Return whether an rdma device can be accessed
  *			     from a specified net namespace or not.
@@ -359,7 +359,8 @@ static struct ib_device *__ib_device_get_by_name(const char *name,
 	unsigned long index;
 
 	xa_for_each (&devices, index, device)
-		if (!strcmp(name, dev_name(&device->dev)))
+		if (rdma_dev_access_netns(device, net) &&
+		    !strcmp(name, dev_name(&device->dev)))
 			return device;
 
 	return NULL;
@@ -437,7 +438,11 @@ int ib_device_set_dim(struct ib_device *ibdev, u8 use_dim)
 	return 0;
 }
 
-/* Pick a free index for the '%d' style @name pattern. */
+/*
+ * Pick a free index for the '%d' style @name pattern within net namespace
+ * @net. Returns the index on success or a negative errno. The caller builds
+ * the final unique device name from the returned index.
+ */
 static int __alloc_name_id(struct net *net, const char *name,
 			   const struct ib_device *skip)
 {
@@ -452,7 +457,7 @@ static int __alloc_name_id(struct net *net, const char *name,
 	xa_for_each (&devices, index, device) {
 		char buf[IB_DEVICE_NAME_MAX];
 
-		if (device == skip)
+		if (device == skip || !rdma_dev_access_netns(device, net))
 			continue;
 		if (sscanf(dev_name(&device->dev), name, &i) != 1)
 			continue;
@@ -1240,7 +1245,8 @@ static __net_init int rdma_dev_init_net(struct net *net)
 }
 
 /*
- * Assign the unique string device name and the unique device index. This is
+ * Assign the unique string device name and the unique device index. The device
+ * name is unique within the net namespace the device is assigned to. This is
  * undone by ib_dealloc_device.
  */
 static int assign_name(struct ib_device *device, const char *name)
@@ -1424,8 +1430,9 @@ static void ib_device_notify_register(struct ib_device *device)
 /**
  * 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.
+ * @name: device name, unique within the device's net namespace. This may
+ *	  include a '%' which will 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.
@@ -1716,6 +1723,7 @@ static bool rdma_dev_name_in_netns(struct ib_device *skip, struct net *net,
 
 	xa_for_each(&devices, index, device)
 		if (device != skip &&
+		    rdma_dev_access_netns(device, net) &&
 		    !strcmp(name, dev_name(&device->dev)))
 			return true;
 
-- 
2.54.0