From: Jiri Pirko Multiple PFs may reside on the same physical chip, running a single firmware. Some of the resources and configurations may be shared among these PFs. Currently, there is no good object to pin the configuration knobs on. Introduce a shared devlink instance, instantiated upon probe of the first PF and removed during remove of the last PF. The shared devlink instance is backed by a faux device, as there is no PCI device related to it. The implementation uses reference counting to manage the lifecycle: each PF that probes calls devlink_shd_get() to get or create the shared instance, and calls devlink_shd_put() when it removes. The shared instance is automatically destroyed when the last PF removes. Example: $ devlink dev pci/0000:08:00.0: nested_devlink: auxiliary/mlx5_core.eth.0 faux/mlx5_core_83013c12b77faa1a30000c82a1045c91: nested_devlink: pci/0000:08:00.0 pci/0000:08:00.1 auxiliary/mlx5_core.eth.0 pci/0000:08:00.1: nested_devlink: auxiliary/mlx5_core.eth.1 auxiliary/mlx5_core.eth.1 Signed-off-by: Jiri Pirko Reviewed-by: Cosmin Ratiu Signed-off-by: Tariq Toukan --- include/net/devlink.h | 6 ++ net/devlink/Makefile | 2 +- net/devlink/sh_dev.c | 163 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 170 insertions(+), 1 deletion(-) create mode 100644 net/devlink/sh_dev.c diff --git a/include/net/devlink.h b/include/net/devlink.h index cb839e0435a1..c453faec8ebf 100644 --- a/include/net/devlink.h +++ b/include/net/devlink.h @@ -1644,6 +1644,12 @@ void devlink_register(struct devlink *devlink); void devlink_unregister(struct devlink *devlink); void devlink_free(struct devlink *devlink); +struct devlink *devlink_shd_get(const char *id, + const struct devlink_ops *ops, + size_t priv_size); +void devlink_shd_put(struct devlink *devlink); +void *devlink_shd_get_priv(struct devlink *devlink); + /** * struct devlink_port_ops - Port operations * @port_split: Callback used to split the port into multiple ones. diff --git a/net/devlink/Makefile b/net/devlink/Makefile index 000da622116a..8f2adb5e5836 100644 --- a/net/devlink/Makefile +++ b/net/devlink/Makefile @@ -1,4 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 obj-y := core.o netlink.o netlink_gen.o dev.o port.o sb.o dpipe.o \ - resource.o param.o region.o health.o trap.o rate.o linecard.o + resource.o param.o region.o health.o trap.o rate.o linecard.o sh_dev.o diff --git a/net/devlink/sh_dev.c b/net/devlink/sh_dev.c new file mode 100644 index 000000000000..acc8d549aaae --- /dev/null +++ b/net/devlink/sh_dev.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */ + +#include +#include + +#include "devl_internal.h" + +static LIST_HEAD(shd_list); +static DEFINE_MUTEX(shd_mutex); /* Protects shd_list and shd->list */ + +/* This structure represents a shared devlink instance, + * there is one created per identifier (e.g., serial number). + */ +struct devlink_shd { + struct list_head list; /* Node in shd list */ + const char *id; /* Identifier string (e.g., serial number) */ + struct faux_device *faux_dev; /* Related faux device */ + refcount_t refcount; /* Reference count */ + char priv[] __aligned(NETDEV_ALIGN); /* Driver private data */ +}; + +static struct devlink_shd *devlink_shd_lookup(const char *id) +{ + struct devlink_shd *shd; + + list_for_each_entry(shd, &shd_list, list) { + if (!strcmp(shd->id, id)) + return shd; + } + + return NULL; +} + +static struct devlink_shd *devlink_shd_create(const char *id, + const struct devlink_ops *ops, + size_t priv_size) +{ + struct faux_device *faux_dev; + struct devlink_shd *shd; + struct devlink *devlink; + + /* Create faux device - probe will be called synchronously */ + faux_dev = faux_device_create(id, NULL, NULL); + if (!faux_dev) + return NULL; + + devlink = devlink_alloc(ops, sizeof(struct devlink_shd) + priv_size, + &faux_dev->dev); + if (!devlink) + goto err_devlink_alloc; + shd = devlink_priv(devlink); + + shd->id = kstrdup(id, GFP_KERNEL); + if (!shd->id) + goto err_kstrdup_id; + shd->faux_dev = faux_dev; + refcount_set(&shd->refcount, 1); + + devl_lock(devlink); + devl_register(devlink); + devl_unlock(devlink); + + list_add_tail(&shd->list, &shd_list); + + return shd; + +err_kstrdup_id: + devlink_free(devlink); + +err_devlink_alloc: + faux_device_destroy(faux_dev); + return NULL; +} + +static void devlink_shd_destroy(struct devlink_shd *shd) +{ + struct devlink *devlink = priv_to_devlink(shd); + struct faux_device *faux_dev = shd->faux_dev; + + list_del(&shd->list); + devl_lock(devlink); + devl_unregister(devlink); + devl_unlock(devlink); + kfree(shd->id); + devlink_free(devlink); + faux_device_destroy(faux_dev); +} + +/** + * devlink_shd_get - Get or create a shared devlink instance + * @id: Identifier string (e.g., serial number) for the shared instance + * @ops: Devlink operations structure + * @priv_size: Size of private data structure + * + * Get an existing shared devlink instance identified by @id, or create + * a new one if it doesn't exist. The device is automatically added to + * the shared instance's device list. Return the devlink instance + * with a reference held. The caller must call devlink_shd_put() when done. + * + * Return: Pointer to the shared devlink instance on success, + * NULL on failure + */ +struct devlink *devlink_shd_get(const char *id, + const struct devlink_ops *ops, + size_t priv_size) +{ + struct devlink_shd *shd; + + if (WARN_ON(!id || !ops)) + return NULL; + + mutex_lock(&shd_mutex); + + shd = devlink_shd_lookup(id); + if (!shd) + shd = devlink_shd_create(id, ops, priv_size); + else + refcount_inc(&shd->refcount); + + mutex_unlock(&shd_mutex); + return shd ? priv_to_devlink(shd) : NULL; +} +EXPORT_SYMBOL_GPL(devlink_shd_get); + +/** + * devlink_shd_put - Release a reference on a shared devlink instance + * @devlink: Shared devlink instance + * + * Release a reference on a shared devlink instance obtained via + * devlink_shd_get(). + */ +void devlink_shd_put(struct devlink *devlink) +{ + struct devlink_shd *shd; + + if (WARN_ON(!devlink)) + return; + + mutex_lock(&shd_mutex); + shd = devlink_priv(devlink); + if (refcount_dec_and_test(&shd->refcount)) + devlink_shd_destroy(shd); + mutex_unlock(&shd_mutex); +} +EXPORT_SYMBOL_GPL(devlink_shd_put); + +/** + * devlink_shd_get_priv - Get private data from shared devlink instance + * @devlink: Devlink instance + * + * Returns a pointer to the driver's private data structure within + * the shared devlink instance. + * + * Return: Pointer to private data + */ +void *devlink_shd_get_priv(struct devlink *devlink) +{ + struct devlink_shd *shd = devlink_priv(devlink); + + return shd->priv; +} +EXPORT_SYMBOL_GPL(devlink_shd_get_priv); -- 2.44.0