Messages in this thread | | | Subject | Re: [PATCH RFC 1/2] brcmfmac: remove interface before notifying listener | From | Arend van Spriel <> | Date | Sat, 18 Jun 2016 21:26:36 +0200 |
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On 18-06-16 20:18, Rafał Miłecki wrote: > So far when receiving event about in-firmware-interface removal we were > notifying our listener and afterwards we were removing Linux interface. >
[snip]
> > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c > index 9da7a4c..5fd1886 100644 > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c > @@ -18,6 +18,7 @@ > #include "brcmu_wifi.h" > #include "brcmu_utils.h" > > +#include "cfg80211.h" > #include "core.h" > #include "debug.h" > #include "tracepoint.h" > @@ -180,10 +181,16 @@ static void brcmf_fweh_handle_if_event(struct brcmf_pub *drvr, > if (ifp && ifevent->action == BRCMF_E_IF_CHANGE) > brcmf_fws_reset_interface(ifp); > > - err = brcmf_fweh_call_event_handler(ifp, emsg->event_code, emsg, data);
The reason for doing this first is because we are passing the ifp, which is netdev_priv(ifp->ndev). In brcmf_remove_interface() we only unregister the netdev, which will end up (after scheduling) in brcmf_free_netdev() thus freeing the ifp. By moving the event handler function ifp may be stale already.
> + if (ifp && ifevent->action == BRCMF_E_IF_DEL) { > + bool rtnl_locked = brcmf_cfg80211_vif_event_armed(drvr->config); > + > + brcmf_remove_interface(ifp, rtnl_locked);
I guess rtnl_locked here means "rtnl_is_locked() by brcmfmac". It actually does not matter who is holding the rtnl_lock. At least when it is brcmfmac it is still a different task, ie. hostapd, iw, etc. Also when brcmf_cfg80211_vif_event_armed() return false there may still be some task holding the rtnl_lock.
Regards, Arend
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