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From: Jiri Pirko <jiri@resnulli.us>
To: linux-rdma@vger.kernel.org
Cc: cgroups@vger.kernel.org, netdev@vger.kernel.org,
	linux-s390@vger.kernel.org, linux-kselftest@vger.kernel.org,
	jgg@ziepe.ca, leon@kernel.org, parav@nvidia.com,
	mbloch@nvidia.com, cmeiohas@nvidia.com, roman.gushchin@linux.dev,
	bvanassche@acm.org, zyjzyj2000@gmail.com, shuah@kernel.org,
	tj@kernel.org, mkoutny@suse.com, hannes@cmpxchg.org,
	alibuda@linux.alibaba.com, dust.li@linux.alibaba.com,
	sidraya@linux.ibm.com, wenjia@linux.ibm.com
Subject: [PATCH rdma-next 09/13] RDMA/cma: Document that CM configfs cannot be net namespace scoped
Date: Thu,  9 Jul 2026 11:55:28 +0200	[thread overview]
Message-ID: <20260709095532.855647-10-jiri@resnulli.us> (raw)
In-Reply-To: <20260709095532.855647-1-jiri@resnulli.us>

From: Jiri Pirko <jiri@nvidia.com>

Document the rdma_cm configfs limitation: configfs is global, so same-named
RDMA devices in different net namespaces cannot both be represented there.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
 Documentation/ABI/testing/configfs-rdma_cm | 4 ++++
 drivers/infiniband/core/cma_configfs.c     | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/Documentation/ABI/testing/configfs-rdma_cm b/Documentation/ABI/testing/configfs-rdma_cm
index 74f9506f42e7..739f7b6a1259 100644
--- a/Documentation/ABI/testing/configfs-rdma_cm
+++ b/Documentation/ABI/testing/configfs-rdma_cm
@@ -12,6 +12,10 @@ Description: 	Interface is used to configure RDMA-cable HCAs in respect to
 		for this HCA has to be created:
 		mkdir -p /config/rdma_cm/<hca>
 
+		Note: configfs has no network namespace support, so this
+		interface cannot represent two devices that share a name in
+		different network namespaces (possible in exclusive netns mode).
+
 
 What: 		/config/rdma_cm/<hca>/ports/<port-num>/default_roce_mode
 Date: 		November 29, 2015
diff --git a/drivers/infiniband/core/cma_configfs.c b/drivers/infiniband/core/cma_configfs.c
index 891e52afb8f4..c389d4e37b6b 100644
--- a/drivers/infiniband/core/cma_configfs.c
+++ b/drivers/infiniband/core/cma_configfs.c
@@ -65,6 +65,10 @@ static struct cma_dev_port_group *to_dev_port_group(struct config_item *item)
 	return container_of(group, struct cma_dev_port_group, group);
 }
 
+/*
+ * configfs is not net namespace aware, so a name shared by devices in
+ * different namespaces resolves to the first match here.
+ */
 static bool filter_by_name(struct ib_device *ib_dev, void *cookie)
 {
 	return !strcmp(dev_name(&ib_dev->dev), cookie);
-- 
2.54.0


  parent reply	other threads:[~2026-07-09  9:56 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-09  9:55 [PATCH rdma-next 00/13] RDMA: Make device names unique per net namespace Jiri Pirko
2026-07-09  9:55 ` [PATCH rdma-next 01/13] RDMA/core: Pass the net namespace to the device name lookups Jiri Pirko
2026-07-09  9:55 ` [PATCH rdma-next 02/13] RDMA/core: Handle device name conflicts when changing net namespace Jiri Pirko
2026-07-10  9:56   ` sashiko-bot
2026-07-09  9:55 ` [PATCH rdma-next 03/13] RDMA/core: Support renaming a device when changing its " Jiri Pirko
2026-07-10  9:56   ` sashiko-bot
2026-07-09  9:55 ` [PATCH rdma-next 04/13] RDMA/nldev: Report net namespace move errors through extack Jiri Pirko
2026-07-09  9:55 ` [PATCH rdma-next 05/13] RDMA/nldev: Allow setting the device name while changing net namespace Jiri Pirko
2026-07-09  9:55 ` [PATCH rdma-next 06/13] net/smc: Look up the pnetid ib device within the " Jiri Pirko
2026-07-10  9:56   ` sashiko-bot
2026-07-09  9:55 ` [PATCH rdma-next 07/13] RDMA/srp: Make the SRP sysfs class net namespace aware Jiri Pirko
2026-07-09  9:55 ` [PATCH rdma-next 08/13] RDMA/cgroup: Scope rdma cgroup device visibility to the net namespace Jiri Pirko
2026-07-09 13:04   ` Michal Koutný
2026-07-10  9:56   ` sashiko-bot
2026-07-09  9:55 ` Jiri Pirko [this message]
2026-07-09  9:55 ` [PATCH rdma-next 10/13] RDMA/core: Document the SELinux ibendport net namespace limitation Jiri Pirko
2026-07-09  9:55 ` [PATCH rdma-next 11/13] RDMA/core: Make device names unique per net namespace Jiri Pirko
2026-07-09  9:55 ` [PATCH rdma-next 12/13] RDMA/rxe: Implement disassociate_ucontext callback Jiri Pirko
2026-07-10  4:21   ` Zhu Yanjun
2026-07-10  9:56   ` sashiko-bot
2026-07-09  9:55 ` [PATCH rdma-next 13/13] RDMA/selftests: Add rxe_netns_names test Jiri Pirko
2026-07-10  4:24   ` Zhu Yanjun
2026-07-10  9:56   ` sashiko-bot

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