Re: [RFC 1/5] iwlwifi: fix drv cleanup on opmode registration failure

On Sun, Feb 19, 2017 at 09:16:01AM +0000, Grumbach, Emmanuel wrote:

quoted

This should in theory fix a detangled drv from the drv list should either of the
opmode modules loaded and handled registration for the drv.

The path of having the opmode registration deal with the drv opmode start is
actually the more common path. The other path, from the async callback is
rathe rare (1/8 or so times for me) -- it happens when the the opmode
driver's init routine completed prior to the driver's async callback opmode
start call.

I'd claim it should never happen unless you have several devices on the system using the same
opmode, or unless you do:
modprobe iwlwifi  #which will load iwl{d,m}vm
rmmod iwl{d,m}vm #and do _not_ remove iwlwifi
modprobe iwlwifi

That is indeed one way one can easily reproduce this. There are however other
ways too. Try a loop of

modprobe -r iwlmvm (which removes iwlwifi) followed by modprobe iwlmvm;

while this check for which path is taken, or better yet check if the
list of drvs is empty on opmode registration. Every now and then I see
the list is empty.

I have a feeling this is then also a rare rarely observed by your QA team
as well, so this code then is also stitching together a set of sequence
calls for both paths.

quoted

Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---

Luca is OOO,  but this looks fine to me.

Reviewed-by ?

  Luis