Subject: Re: [PATCH rdma-next 04/12] RDMA/core: Support IB sub device with type "SMI"

From: Leon Romanovsky <[email-masked]>
Date: Mon, 1 Jul 2024 14:55:32 +0300

On Sat, Jun 29, 2024 at 08:14:56AM +0800, Zhu Yanjun wrote:
> 在 2024/6/17 0:08, Leon Romanovsky 写道:
> > From: Mark Zhang <[email-masked]>
> > 
> > This patch adds 2 APIs, as well as driver operations to support adding
> > and deleting an IB sub device, which provides part of functionalities
> > of it's parent.
> > 
> > A sub device has a type; for a sub device with type "SMI", it provides
> > the smi capability through umad for its parent, meaning uverb is not
> > supported.
> > 
> > A sub device cannot live without a parent. So when a parent is
> > released, all it's sub devices are released as well.
> > 
> > Signed-off-by: Mark Zhang <[email-masked]>
> > Signed-off-by: Leon Romanovsky <[email-masked]>
> > ---
> >   drivers/infiniband/core/device.c      | 68 +++++++++++++++++++++++++++
> >   drivers/infiniband/core/uverbs_main.c |  3 +-
> >   include/rdma/ib_verbs.h               | 43 +++++++++++++++++
> >   include/uapi/rdma/rdma_netlink.h      |  5 ++
> >   4 files changed, 118 insertions(+), 1 deletion(-)

<...>

> > +int ib_del_sub_device_and_put(struct ib_device *sub)
> > +{
> > +	struct ib_device *parent = sub->parent;
> > +
> > +	if (!parent)
> > +		return -EOPNOTSUPP;
> > +
> > +	mutex_lock(&parent->subdev_lock);
> 
> mutex_destroy of subdev_lock is missing. When mutex_lock is called, it had
> better call mutex_destroy when the mutex lock is not used any more.
> Other mutex locks in this file, for example subdev_lock and subdev_lock,
> call mutex_destroy in the function ib_device_release.
> 
> Perhaps subdev_lock can also call mutex_destroy in ib_device_release?

Thanks, I will add this fixup to the series.

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 7aaf2b4c1844..7b418c717f29 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -503,6 +503,7 @@ static void ib_device_release(struct device *device)
                          rcu_head);
        }

+       mutex_destroy(&dev->subdev_lock);
        mutex_destroy(&dev->unregistration_lock);
        mutex_destroy(&dev->compat_devs_mutex);

Thanks

> 
> Zhu Yanjun
> 
> > +	list_del(&sub->subdev_list);
> > +	mutex_unlock(&parent->subdev_lock);
> > +
> > +	ib_device_put(sub);
> > +	parent->ops.del_sub_dev(sub);
> > +	ib_device_put(parent);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(ib_del_sub_device_and_put);
> > +
> >   #ifdef CONFIG_INFINIBAND_VIRT_DMA
> >   int ib_dma_virt_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents)
> >   {
> > diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
> > index 495d5a5d0373..bc099287de9a 100644
> > --- a/drivers/infiniband/core/uverbs_main.c
> > +++ b/drivers/infiniband/core/uverbs_main.c
> > @@ -1114,7 +1114,8 @@ static int ib_uverbs_add_one(struct ib_device *device)
> >   	struct ib_uverbs_device *uverbs_dev;
> >   	int ret;
> > -	if (!device->ops.alloc_ucontext)
> > +	if (!device->ops.alloc_ucontext ||
> > +	    device->type == RDMA_DEVICE_TYPE_SMI)
> >   		return -EOPNOTSUPP;
> >   	uverbs_dev = kzalloc(sizeof(*uverbs_dev), GFP_KERNEL);
> > diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> > index 477bf9dd5e71..bebc2d22f466 100644
> > --- a/include/rdma/ib_verbs.h
> > +++ b/include/rdma/ib_verbs.h
> > @@ -2661,6 +2661,18 @@ struct ib_device_ops {
> >   	 */
> >   	int (*get_numa_node)(struct ib_device *dev);
> > +	/**
> > +	 * add_sub_dev - Add a sub IB device
> > +	 */
> > +	struct ib_device *(*add_sub_dev)(struct ib_device *parent,
> > +					 enum rdma_nl_dev_type type,
> > +					 const char *name);
> > +
> > +	/**
> > +	 * del_sub_dev - Delete a sub IB device
> > +	 */
> > +	void (*del_sub_dev)(struct ib_device *sub_dev);
> > +
> >   	DECLARE_RDMA_OBJ_SIZE(ib_ah);
> >   	DECLARE_RDMA_OBJ_SIZE(ib_counters);
> >   	DECLARE_RDMA_OBJ_SIZE(ib_cq);
> > @@ -2771,6 +2783,15 @@ struct ib_device {
> >   	char iw_ifname[IFNAMSIZ];
> >   	u32 iw_driver_flags;
> >   	u32 lag_flags;
> > +
> > +	/* A parent device has a list of sub-devices */
> > +	struct mutex subdev_lock;
> > +	struct list_head subdev_list_head;
> > +
> > +	/* A sub device has a type and a parent */
> > +	enum rdma_nl_dev_type type;
> > +	struct ib_device *parent;
> > +	struct list_head subdev_list;
> >   };
> >   static inline void *rdma_zalloc_obj(struct ib_device *dev, size_t size,
> > @@ -4820,4 +4841,26 @@ static inline u16 rdma_get_udp_sport(u32 fl, u32 lqpn, u32 rqpn)
> >   const struct ib_port_immutable*
> >   ib_port_immutable_read(struct ib_device *dev, unsigned int port);
> > +
> > +/** ib_add_sub_device - Add a sub IB device on an existing one
> > + *
> > + * @parent: The IB device that needs to add a sub device
> > + * @type: The type of the new sub device
> > + * @name: The name of the new sub device
> > + *
> > + *
> > + * Return 0 on success, an error code otherwise
> > + */
> > +int ib_add_sub_device(struct ib_device *parent,
> > +		      enum rdma_nl_dev_type type,
> > +		      const char *name);
> > +
> > +
> > +/** ib_del_sub_device_and_put - Delect an IB sub device while holding a 'get'
> > + *
> > + * @sub: The sub device that is going to be deleted
> > + *
> > + * Return 0 on success, an error code otherwise
> > + */
> > +int ib_del_sub_device_and_put(struct ib_device *sub);
> >   #endif /* IB_VERBS_H */
> > diff --git a/include/uapi/rdma/rdma_netlink.h b/include/uapi/rdma/rdma_netlink.h
> > index a214fc259f28..d15ee16be722 100644
> > --- a/include/uapi/rdma/rdma_netlink.h
> > +++ b/include/uapi/rdma/rdma_netlink.h
> > @@ -602,4 +602,9 @@ enum rdma_nl_counter_mask {
> >   	RDMA_COUNTER_MASK_QP_TYPE = 1,
> >   	RDMA_COUNTER_MASK_PID = 1 << 1,
> >   };
> > +
> > +/* Supported rdma device types. */
> > +enum rdma_nl_dev_type {
> > +	RDMA_DEVICE_TYPE_SMI = 1,
> > +};
> >   #endif /* _UAPI_RDMA_NETLINK_H */
>