Re: [patch net-next RFC] net: dsa: move port_setup/teardown to be called outside devlink port registered area

Vladimir Oltean
2022-07-26T15:21:08Z

On Tue, Jul 26, 2022 at 04:45:44PM +0200, Jiri Pirko wrote:
> Oh yes, could you please try together with following patch? (nevermind
> chicken-egg problem you may spot now)

Duly ignoring ;)

> Subject: [patch net-next RFC] net: devlink: convert region creation/destroy()
> to be forbidden on registered devlink/port
>
> No need to create or destroy region when devlink or devlink ports are
> registered. Limit the possibility to call the region create/destroy()
> only for non-registered devlink or devlink port. Benefit from that and
> avoid need to take devl_lock.
>
> Signed-off-by: Jiri Pirko <jiri@nvidia.com>
> ---
> drivers/net/netdevsim/dev.c | 8 ++--
> include/net/devlink.h | 5 ---
> net/core/devlink.c | 78 ++++++++-----------------------------
> 3 files changed, 20 insertions(+), 71 deletions(-)
>
> diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
> index 925dc8a5254d..3f0c19e30650 100644
> --- a/drivers/net/netdevsim/dev.c
> +++ b/drivers/net/netdevsim/dev.c
> @@ -557,15 +557,15 @@ static int nsim_dev_dummy_region_init(struct nsim_dev *nsim_dev,
> struct devlink *devlink)
> {
> nsim_dev->dummy_region =
> - devl_region_create(devlink, &dummy_region_ops,
> - NSIM_DEV_DUMMY_REGION_SNAPSHOT_MAX,
> - NSIM_DEV_DUMMY_REGION_SIZE);
> + devlink_region_create(devlink, &dummy_region_ops,
> + NSIM_DEV_DUMMY_REGION_SNAPSHOT_MAX,
> + NSIM_DEV_DUMMY_REGION_SIZE);
> return PTR_ERR_OR_ZERO(nsim_dev->dummy_region);
> }
>
> static void nsim_dev_dummy_region_exit(struct nsim_dev *nsim_dev)
> {
> - devl_region_destroy(nsim_dev->dummy_region);
> + devlink_region_destroy(nsim_dev->dummy_region);
> }
>
> static int
> diff --git a/include/net/devlink.h b/include/net/devlink.h
> index 9edb4a28cf30..2416750e050d 100644
> --- a/include/net/devlink.h
> +++ b/include/net/devlink.h
> @@ -1666,10 +1666,6 @@ int devlink_param_driverinit_value_get(struct devlink *devlink, u32 param_id,
> int devlink_param_driverinit_value_set(struct devlink *devlink, u32 param_id,
> union devlink_param_value init_val);
> void devlink_param_value_changed(struct devlink *devlink, u32 param_id);
> -struct devlink_region *devl_region_create(struct devlink *devlink,
> - const struct devlink_region_ops *ops,
> - u32 region_max_snapshots,
> - u64 region_size);
> struct devlink_region *
> devlink_region_create(struct devlink *devlink,
> const struct devlink_region_ops *ops,
> @@ -1678,7 +1674,6 @@ struct devlink_region *
> devlink_port_region_create(struct devlink_port *port,
> const struct devlink_port_region_ops *ops,
> u32 region_max_snapshots, u64 region_size);
> -void devl_region_destroy(struct devlink_region *region);
> void devlink_region_destroy(struct devlink_region *region);
> void devlink_port_region_destroy(struct devlink_region *region);
>
> diff --git a/net/core/devlink.c b/net/core/devlink.c
> index 4e0c4f9265e8..15d28aba69fc 100644
> --- a/net/core/devlink.c
> +++ b/net/core/devlink.c
> @@ -5701,8 +5701,7 @@ static void devlink_nl_region_notify(struct devlink_region *region,
> struct sk_buff *msg;
>
> WARN_ON(cmd != DEVLINK_CMD_REGION_NEW && cmd != DEVLINK_CMD_REGION_DEL);
> - if (!xa_get_mark(&devlinks, devlink->index, DEVLINK_REGISTERED))
> - return;
> + ASSERT_DEVLINK_REGISTERED(devlink);
>
> msg = devlink_nl_region_notify_build(region, snapshot, cmd, 0, 0);
> if (IS_ERR(msg))
> @@ -11131,21 +11130,22 @@ void devlink_param_value_changed(struct devlink *devlink, u32 param_id)
> EXPORT_SYMBOL_GPL(devlink_param_value_changed);
>
> /**
> - * devl_region_create - create a new address region
> + * devlink_region_create - create a new address region
> *
> * @devlink: devlink
> * @ops: region operations and name
> * @region_max_snapshots: Maximum supported number of snapshots for region
> * @region_size: size of region
> */
> -struct devlink_region *devl_region_create(struct devlink *devlink,
> - const struct devlink_region_ops *ops,
> - u32 region_max_snapshots,
> - u64 region_size)
> +struct devlink_region *
> +devlink_region_create(struct devlink *devlink,
> + const struct devlink_region_ops *ops,
> + u32 region_max_snapshots,
> + u64 region_size)
> {
> struct devlink_region *region;
>
> - devl_assert_locked(devlink);
> + ASSERT_DEVLINK_NOT_REGISTERED(devlink);
>
> if (WARN_ON(!ops) || WARN_ON(!ops->destructor))
> return ERR_PTR(-EINVAL);
> @@ -11164,35 +11164,9 @@ struct devlink_region *devl_region_create(struct devlink *devlink,
> INIT_LIST_HEAD(&region->snapshot_list);
> mutex_init(&region->snapshot_lock);
> list_add_tail(&region->list, &devlink->region_list);
> - devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_NEW);
>
> return region;
> }
> -EXPORT_SYMBOL_GPL(devl_region_create);
> -
> -/**
> - * devlink_region_create - create a new address region
> - *
> - * @devlink: devlink
> - * @ops: region operations and name
> - * @region_max_snapshots: Maximum supported number of snapshots for region
> - * @region_size: size of region
> - *
> - * Context: Takes and release devlink->lock <mutex>.
> - */
> -struct devlink_region *
> -devlink_region_create(struct devlink *devlink,
> - const struct devlink_region_ops *ops,
> - u32 region_max_snapshots, u64 region_size)
> -{
> - struct devlink_region *region;
> -
> - devl_lock(devlink);
> - region = devl_region_create(devlink, ops, region_max_snapshots,
> - region_size);
> - devl_unlock(devlink);
> - return region;
> -}
> EXPORT_SYMBOL_GPL(devlink_region_create);
>
> /**

Were you on net-next when you generated this patch? Here's what I have
at 11164:

devlink_port_region_create:
if (devlink_port_region_get_by_name(port, ops->name)) {
err = -EEXIST;
goto unlock;
}

region = kzalloc(sizeof(*region), GFP_KERNEL);
if (!region) {

My end of devl_region_create() and start of devlink_region_create() are
at 11106, but notice how I lack the mutex_init(&region->snapshot_lock)
that you have in your context:

INIT_LIST_HEAD(&region->snapshot_list);
list_add_tail(&region->list, &devlink->region_list);
devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_NEW);

return region;
}
EXPORT_SYMBOL_GPL(devl_region_create);

Would you mind regenerating this patch rather than letting me bodge it?