Subject: Re: [patch net-next v3 06/14] rocker: introduce worlds infrastructure

From: John Fastabend <[email-masked]>
Date: Tue, 06 Oct 2015 09:19:14 -0700

On 15-10-06 09:06 AM, Scott Feldman wrote:
> On Tue, Oct 6, 2015 at 12:51 AM, Jiri Pirko <[email-masked]> wrote:
>> From: Jiri Pirko <[email-masked]>
>>
>> This is another step on the way to per-world clean cut. Introduce world
>> ops hooks which each world can implement in world-specific way.
>> Also introduce world infrastructure including function for port worlds
>> change.
>>
>> Signed-off-by: Jiri Pirko <[email-masked]>
>> ---
>> v1->v2:
>>  - removed functions to change worlds based on name, as rtnl mode
>>    set patch is removed from patchset.
>> v2->v3:
>>  - fix checks in rocker_world_port_open and rocker_world_port_stop
>> ---
>>  drivers/net/ethernet/rocker/rocker.h      |  56 ++++
>>  drivers/net/ethernet/rocker/rocker_main.c | 464 +++++++++++++++++++++++++++++-
>>  2 files changed, 519 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/rocker/rocker.h b/drivers/net/ethernet/rocker/rocker.h
>> index 650caa0..d49bc5d 100644
>> --- a/drivers/net/ethernet/rocker/rocker.h
>> +++ b/drivers/net/ethernet/rocker/rocker.h
>> @@ -12,7 +12,11 @@
>>  #ifndef _ROCKER_H
>>  #define _ROCKER_H
>>
>> +#include <linux/kernel.h>
>>  #include <linux/types.h>
>> +#include <linux/netdevice.h>
>> +#include <net/neighbour.h>
>> +#include <net/switchdev.h>
>>
>>  #include "rocker_hw.h"
>>
>> @@ -24,4 +28,56 @@ struct rocker_desc_info {
>>         dma_addr_t mapaddr;
>>  };
>>
>> +struct rocker;
>> +struct rocker_port;
>> +
>> +struct rocker_world_ops {
>> +       const char *kind;
>> +       size_t priv_size;
>> +       size_t port_priv_size;
>> +       u8 mode;
>> +       int (*init)(struct rocker *rocker, void *priv);
>> +       void (*fini)(void *priv);
>> +       int (*port_init)(struct rocker_port *rocker_port, void *priv,
>> +                        void *port_priv);
>> +       void (*port_fini)(void *port_priv);
>> +       int (*port_open)(void *port_priv);
>> +       void (*port_stop)(void *port_priv);
>> +       int (*port_attr_stp_state_set)(void *port_priv, u8 state,
>> +                                      struct switchdev_trans *trans);
>> +       int (*port_attr_bridge_flags_set)(void *port_priv,
>> +                                         unsigned long brport_flags,
>> +                                         struct switchdev_trans *trans);
>> +       int (*port_attr_bridge_flags_get)(void *port_priv,
>> +                                         unsigned long *p_brport_flags);
>> +       int (*port_obj_vlan_add)(void *port_priv,
>> +                                const struct switchdev_obj_port_vlan *vlan,
>> +                                struct switchdev_trans *trans);
>> +       int (*port_obj_vlan_del)(void *port_priv,
>> +                                const struct switchdev_obj_port_vlan *vlan);
>> +       int (*port_obj_vlan_dump)(void *port_priv,
>> +                                 struct switchdev_obj_port_vlan *vlan,
>> +                                 switchdev_obj_dump_cb_t *cb);
>> +       int (*port_obj_fib4_add)(void *port_priv,
>> +                                const struct switchdev_obj_ipv4_fib *fib4,
>> +                                struct switchdev_trans *trans);
>> +       int (*port_obj_fib4_del)(void *port_priv,
>> +                                const struct switchdev_obj_ipv4_fib *fib4);
>> +       int (*port_obj_fdb_add)(void *port_priv,
>> +                               const struct switchdev_obj_port_fdb *fdb,
>> +                               struct switchdev_trans *trans);
>> +       int (*port_obj_fdb_del)(void *port_priv,
>> +                               const struct switchdev_obj_port_fdb *fdb);
>> +       int (*port_obj_fdb_dump)(void *port_priv,
>> +                                struct switchdev_obj_port_fdb *fdb,
>> +                                switchdev_obj_dump_cb_t *cb);
>> +       int (*port_master_linked)(void *port_priv, struct net_device *master);
>> +       int (*port_master_unlinked)(void *port_priv, struct net_device *master);
>> +       int (*port_neigh_update)(void *port_priv, struct neighbour *n);
>> +       int (*port_neigh_destroy)(void *port_priv, struct neighbour *n);
>> +       int (*port_ev_mac_vlan_seen)(void *port_priv,
>> +                                    const unsigned char *addr,
>> +                                    __be16 vlan_id);
>> +};
> 
> Using void * in these ops is unacceptable, I can't agree to this patch.
> 
> There is a much cleaner way to architect this.  If you look at the ops
> defined, they're mostly duplicates of the already defined
> switchdev_ops.  It would be much cleaner to:
> 
> 0) set port mode on qemu/rocker (the device)
> 1) get the port mode on port probe
> 2) based on port mode, set the switchdev_ops to point to the port mode
> world switchdev_ops
> 3) sub-class rocker_port, like I mentioned in before, to store
> world-specific stuff in rocker_port
> 
> I don't buy the argument that we need to change port mode dynamically
> from the driver.  Set it at the device and be done.
> 

Maybe as a reference this strikes me as similar to how we do multiple
device support in a single driver like ixgbe or fm10k (the two I'm most
familiar with). At probe time we read the device id and then stub in
the specific callbacks for that device.

Sorry I'm still hung up on the multiple worlds thing, is it really
trying to model different devices under a single driver? In which case
maybe rather than port mode expose it as its own device id. Just a
thought.

Also I wonder if some of these routines can be broken out more? I'm
missing how opening a port is so different across these worlds. Probably
need to poke at the qemu model a bit more.

.John