New NAPI API: Need for netif_napi_remove() ?!

New NAPI API: Need for netif_napi_remove() ?!

[Kok, Auke]

David,

 From an old thread:

 > 5) Since, in the NETPOLL case, netif_napi_init() adds the NAPI struct
 >   to the per-device list I renamed it to netif_napi_add().  Currently
 >   no teardown is really necessary, anything that would need to be done
 >   would be driver internal, so I didn't create the corollary
 >   netif_napi_remove() for the time being.  Let's not add it unless it
 >   really becomes necessary.

while coding the NAPI API changes into the ixgbe driver, I notice that I'm in 
need for an implementation for netif_napi_remove(). The ixgbe driver itself 
already modifies it's polling routing on open() and close() based on whether it 
was able to acquire MSI-X vectors or not, and can thus logically change as the 
system suspends/resumes and new hardware is inserted that change the balance in 
the MSI-X vectors in the system. Or, even more bluntly, all MSI support is 
disabled and we want the driver to come up in legacy mode and use a completely 
different poll routine alltogether. We can't do this at probe time.

In any case I think we have a legitimate case for netif_napi_remove() to be 
implemented.

Auke

Re: New NAPI API: Need for netif_napi_remove() ?!

[Kok, Auke]

Kok, Auke wrote:
> David,
> 
>  From an old thread:
> 
>  > 5) Since, in the NETPOLL case, netif_napi_init() adds the NAPI struct
>  >   to the per-device list I renamed it to netif_napi_add().  Currently
>  >   no teardown is really necessary, anything that would need to be done
>  >   would be driver internal, so I didn't create the corollary
>  >   netif_napi_remove() for the time being.  Let's not add it unless it
>  >   really becomes necessary.
> 
> while coding the NAPI API changes into the ixgbe driver, I notice that I'm in 
> need for an implementation for netif_napi_remove(). The ixgbe driver itself 
> already modifies it's polling routing on open() and close() based on whether it 
> was able to acquire MSI-X vectors or not, and can thus logically change as the 
> system suspends/resumes and new hardware is inserted that change the balance in 
> the MSI-X vectors in the system. Or, even more bluntly, all MSI support is 
> disabled and we want the driver to come up in legacy mode and use a completely 
> different poll routine alltogether. We can't do this at probe time.
> 
> In any case I think we have a legitimate case for netif_napi_remove() to be 
> implemented.


hm, I spoke too soon, I think I can get by for now by just modifying 
adapter->napi.poll when needed, and this would be clean enough for now. This 
might change as I enable multiqueue in this driver later though.

Auke

Re: New NAPI API: Need for netif_napi_remove() ?!

[David Miller]

From: "Kok, Auke" <sofar@foo-projects.org>
Date: Mon, 10 Sep 2007 17:27:33 -0700

> hm, I spoke too soon, I think I can get by for now by just modifying 
> adapter->napi.poll when needed, and this would be clean enough for now. This 
> might change as I enable multiqueue in this driver later though.

Ok, let me know if things change.

The only reason it doesn't exist was the lack of any need.