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Thu, 12 Mar 2026 03:04:20 -0700 (PDT) Received: from localhost ([85.163.81.98]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-439fe19abbasm6336477f8f.6.2026.03.12.03.04.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2026 03:04:20 -0700 (PDT) From: Jiri Pirko To: netdev@vger.kernel.org Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, donald.hunter@gmail.com, corbet@lwn.net, skhan@linuxfoundation.org, saeedm@nvidia.com, leon@kernel.org, tariqt@nvidia.com, mbloch@nvidia.com, przemyslaw.kitszel@intel.com, mschmidt@redhat.com, andrew+netdev@lunn.ch, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, chuck.lever@oracle.com, matttbe@kernel.org, cjubran@nvidia.com, daniel.zahka@gmail.com, linux-doc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH net-next v4 10/13] devlink: allow devlink instance allocation without a backing device Date: Thu, 12 Mar 2026 11:04:04 +0100 Message-ID: <20260312100407.551173-11-jiri@resnulli.us> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20260312100407.551173-1-jiri@resnulli.us> References: <20260312100407.551173-1-jiri@resnulli.us> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jiri Pirko Allow devlink_alloc_ns() to be called with dev=NULL to support device-less devlink instances. When dev is NULL, the instance is identified over netlink using "devlink_index" as bus_name and the decimal index value as dev_name. Signed-off-by: Jiri Pirko --- v2->v3: - rebased on top of __devlink_alloc() introduction - removed dev check before dev_warn (devl_warn is used now) - rebased on top of devlink->bus_name and devlink->dev_name removal - rebased on top of devlink->dev_driver addition v1->v2: - moved DEVLINK_INDEX_BUS_NAME definition to patch #5 - added comment to dev arg that it can be NULL - fixed the index sprintf for dev-less --- net/devlink/core.c | 23 ++++++++++++++++++----- net/devlink/dev.c | 8 ++++---- net/devlink/devl_internal.h | 5 +++-- 3 files changed, 25 insertions(+), 11 deletions(-) diff --git a/net/devlink/core.c b/net/devlink/core.c index 34eb06d88544..eeb6a71f5f56 100644 --- a/net/devlink/core.c +++ b/net/devlink/core.c @@ -250,13 +250,13 @@ EXPORT_SYMBOL_GPL(devlink_to_dev); const char *devlink_bus_name(const struct devlink *devlink) { - return devlink->dev->bus->name; + return devlink->dev ? devlink->dev->bus->name : DEVLINK_INDEX_BUS_NAME; } EXPORT_SYMBOL_GPL(devlink_bus_name); const char *devlink_dev_name(const struct devlink *devlink) { - return dev_name(devlink->dev); + return devlink->dev ? dev_name(devlink->dev) : devlink->dev_name_index; } EXPORT_SYMBOL_GPL(devlink_dev_name); @@ -329,7 +329,10 @@ static void devlink_release(struct work_struct *work) mutex_destroy(&devlink->lock); lockdep_unregister_key(&devlink->lock_key); - put_device(devlink->dev); + if (devlink->dev) + put_device(devlink->dev); + else + kfree(devlink->dev_name_index); kvfree(devlink); } @@ -432,7 +435,7 @@ struct devlink *__devlink_alloc(const struct devlink_ops *ops, size_t priv_size, static u32 last_id; int ret; - WARN_ON(!ops || !dev || !dev_driver); + WARN_ON(!ops || !dev_driver); if (!devlink_reload_actions_valid(ops)) return NULL; @@ -445,7 +448,14 @@ struct devlink *__devlink_alloc(const struct devlink_ops *ops, size_t priv_size, if (ret < 0) goto err_xa_alloc; - devlink->dev = get_device(dev); + if (dev) { + devlink->dev = get_device(dev); + } else { + devlink->dev_name_index = kasprintf(GFP_KERNEL, "%u", devlink->index); + if (!devlink->dev_name_index) + goto err_kasprintf; + } + devlink->ops = ops; devlink->dev_driver = dev_driver; xa_init_flags(&devlink->ports, XA_FLAGS_ALLOC); @@ -471,6 +481,8 @@ struct devlink *__devlink_alloc(const struct devlink_ops *ops, size_t priv_size, return devlink; +err_kasprintf: + xa_erase(&devlinks, devlink->index); err_xa_alloc: kvfree(devlink); return NULL; @@ -492,6 +504,7 @@ struct devlink *devlink_alloc_ns(const struct devlink_ops *ops, size_t priv_size, struct net *net, struct device *dev) { + WARN_ON(!dev); return __devlink_alloc(ops, priv_size, net, dev, dev->driver); } EXPORT_SYMBOL_GPL(devlink_alloc_ns); diff --git a/net/devlink/dev.c b/net/devlink/dev.c index e3a36de4f4ae..57b2b8f03543 100644 --- a/net/devlink/dev.c +++ b/net/devlink/dev.c @@ -453,7 +453,8 @@ int devlink_reload(struct devlink *devlink, struct net *dest_net, * (e.g., PCI reset) and to close possible races between these * operations and probe/remove. */ - device_lock_assert(devlink->dev); + if (devlink->dev) + device_lock_assert(devlink->dev); memcpy(remote_reload_stats, devlink->stats.remote_reload_stats, sizeof(remote_reload_stats)); @@ -854,7 +855,7 @@ int devlink_info_version_running_put_ext(struct devlink_info_req *req, } EXPORT_SYMBOL_GPL(devlink_info_version_running_put_ext); -static int devlink_nl_driver_info_get(struct device_driver *drv, +static int devlink_nl_driver_info_get(const struct device_driver *drv, struct devlink_info_req *req) { if (!drv) @@ -872,7 +873,6 @@ devlink_nl_info_fill(struct sk_buff *msg, struct devlink *devlink, enum devlink_command cmd, u32 portid, u32 seq, int flags, struct netlink_ext_ack *extack) { - struct device *dev = devlink_to_dev(devlink); struct devlink_info_req req = {}; void *hdr; int err; @@ -892,7 +892,7 @@ devlink_nl_info_fill(struct sk_buff *msg, struct devlink *devlink, goto err_cancel_msg; } - err = devlink_nl_driver_info_get(dev->driver, &req); + err = devlink_nl_driver_info_get(devlink->dev_driver, &req); if (err) goto err_cancel_msg; diff --git a/net/devlink/devl_internal.h b/net/devlink/devl_internal.h index cb2ffef1ac2d..7dfb7cdd2d23 100644 --- a/net/devlink/devl_internal.h +++ b/net/devlink/devl_internal.h @@ -49,6 +49,7 @@ struct devlink { struct xarray snapshot_ids; struct devlink_dev_stats stats; struct device *dev; + const char *dev_name_index; const struct device_driver *dev_driver; possible_net_t _net; /* Serializes access to devlink instance specific objects such as @@ -119,7 +120,7 @@ static inline bool devl_is_registered(struct devlink *devlink) static inline void devl_dev_lock(struct devlink *devlink, bool dev_lock) { - if (dev_lock) + if (dev_lock && devlink->dev) device_lock(devlink->dev); devl_lock(devlink); } @@ -127,7 +128,7 @@ static inline void devl_dev_lock(struct devlink *devlink, bool dev_lock) static inline void devl_dev_unlock(struct devlink *devlink, bool dev_lock) { devl_unlock(devlink); - if (dev_lock) + if (dev_lock && devlink->dev) device_unlock(devlink->dev); } -- 2.51.1