New NAPI API: Need for netif_napi_remove() ?!

["Kok, Auke" <auke-jan.h.kok@intel.com>]

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