Re: [PATCH net-next RFC v1 3/4] devlink: Add hierarchy between traps in device level and port level

[Aya Levin]

On 9/6/2020 6:58 PM, Ido Schimmel wrote:
On Wed, Sep 02, 2020 at 06:32:13PM +0300, Aya Levin wrote:
Managing large scale port's traps may be complicated. This patch
introduces a shortcut: when setting a trap on a device and this trap is
not registered on this device, the action will take place on all related
ports that did register this trap.

I'm not really a fan of this and I'm not sure there is precedent for
something similar. Also, it's an optimization, so I wouldn't put it as
part of the first submission before you gather some operational
experience with the initial interface.

I thought it was a nice idea but I agree that this is an optimization 
and can be dropped from preliminary submission

In addition, I find it very unintuitive for users. When I do 'devlink
trap show' I will not see anything. I will only see the traps when I
issue 'devlink port trap show', yet 'devlink trap set ...' is expected
to work.

Lets assume that this is a valid change, it would be better implemented
with my suggestion from the previous patch: When devlink sees that a
trap is registered on all the ports it can auto-register a new
per-device trap and user space gets the appropriate notification.


Signed-off-by: Aya Levin <a...@mellanox.com>
---
  net/core/devlink.c | 43 +++++++++++++++++++++++++++++++++----------
  1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index b13e1b40bf1c..dea5482b2517 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -6501,23 +6501,46 @@ static int devlink_nl_cmd_trap_set_doit(struct sk_buff 
*skb,
        struct devlink *devlink = info->user_ptr[0];
        struct devlink_trap_mngr *trap_mngr;
        struct devlink_trap_item *trap_item;
+       struct devlink_port *devlink_port;
        int err;
  
-	trap_mngr = devlink_trap_get_trap_mngr_from_info(devlink, info);
-       if (list_empty(&trap_mngr->trap_list))
-               return -EOPNOTSUPP;
+       devlink_port = devlink_port_get_from_attrs(devlink, info->attrs);
+       if (IS_ERR(devlink_port)) {
+               trap_mngr =  &devlink->trap_mngr;
+               if (list_empty(&trap_mngr->trap_list))
+                       goto loop_over_ports;
  
-	trap_item = devlink_trap_item_get_from_info(trap_mngr, info);
-       if (!trap_item) {
-               NL_SET_ERR_MSG_MOD(extack, "Device did not register this trap");
-               return -ENOENT;
+               trap_item = devlink_trap_item_get_from_info(trap_mngr, info);
+               if (!trap_item)
+                       goto loop_over_ports;
+       } else {
+               trap_mngr = &devlink_port->trap_mngr;
+               if (list_empty(&trap_mngr->trap_list))
+                       return -EOPNOTSUPP;
+
+               trap_item = devlink_trap_item_get_from_info(trap_mngr, info);
+               if (!trap_item) {
+                       NL_SET_ERR_MSG_MOD(extack, "Port did not register this 
trap");
+                       return -ENOENT;
+               }
        }
        return devlink_trap_action_set(devlink, trap_mngr, trap_item, info);
  
-	err = devlink_trap_action_set(devlink, trap_mngr, trap_item, info);
-       if (err)
-               return err;
+loop_over_ports:
+       if (list_empty(&devlink->port_list))
+               return -EOPNOTSUPP;
+       list_for_each_entry(devlink_port, &devlink->port_list, list) {
+               trap_mngr = &devlink_port->trap_mngr;
+               if (list_empty(&trap_mngr->trap_list))
+                       continue;
  
+		trap_item = devlink_trap_item_get_from_info(trap_mngr, info);
+               if (!trap_item)
+                       continue;
+               err = devlink_trap_action_set(devlink, trap_mngr, trap_item, 
info);
+               if (err)
+                       return err;
+       }
        return 0;
  }
  
--
2.14.1