From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= Subject: [PATCH 1/2] brcmfmac: delete interface directly in code that sent fw request Date: Wed, 29 Jun 2016 21:54:26 +0200 Message-ID: <1467230067-3302-2-git-send-email-zajec5@gmail.com> References: <1466353420-30998-1-git-send-email-zajec5@gmail.com> <1467230067-3302-1-git-send-email-zajec5@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= , Arend van Spriel , Franky Lin , Hante Meuleman , Pieter-Paul Giesberts , "Franky (Zhenhui) Lin" , linux-wireless@vger.kernel.org (open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER), brcm80211-dev-list.pdl@broadcom.com (open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER), netdev@vger.kernel.org (open list:NETWORKING DRIVERS), linux-kernel@vger.kernel.org (open list) To: Kalle Valo Return-path: Received: from mail-lf0-f65.google.com ([209.85.215.65]:35818 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751839AbcF2TzP (ORCPT ); Wed, 29 Jun 2016 15:55:15 -0400 In-Reply-To: <1467230067-3302-1-git-send-email-zajec5@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: So far when receiving event about in-firmware-interface removal our event worker was notifying listener and afterwards it was removing Linu= x interface. =46irst of all it was resulting in slightly unexpected order. The liste= ner (del_virtual_intf callback) was (usually) returning with success before we even called unregister_netdev(ice). Please note this couldn't be simply fixed by changing order of calls in brcmf_fweh_handle_if_event as unregistering interface earlier could fre= e struct brcmf_if. Another problem of current implementation are possible lockups. Focus o= n the time slot between calling event handler and removing Linux interface. During that time original caller may leave (unlocking rtnl semaphore) *and* another call to the same code may be done (locking it again). If that happens our event handler will stuck at removing Linux interface, it won't handle another event and will block process holding rtnl lock. This can be simply solved by unregistering interface in a proper callback, right after receiving confirmation event from firmware. This only required modifying worker to don't unregister on its own if there is someone waiting for the event. Signed-off-by: Rafa=C5=82 Mi=C5=82ecki --- drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c | 10 ++++++++-= - drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +-- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c b/= drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c index 9da7a4c..79c081f 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" =20 +#include "cfg80211.h" #include "core.h" #include "debug.h" #include "tracepoint.h" @@ -182,8 +183,13 @@ static void brcmf_fweh_handle_if_event(struct brcm= f_pub *drvr, =20 err =3D brcmf_fweh_call_event_handler(ifp, emsg->event_code, emsg, da= ta); =20 - if (ifp && ifevent->action =3D=3D BRCMF_E_IF_DEL) - brcmf_remove_interface(ifp, false); + if (ifp && ifevent->action =3D=3D BRCMF_E_IF_DEL) { + bool armed =3D brcmf_cfg80211_vif_event_armed(drvr->config); + + /* Default handling in case no-one waits for this event */ + if (!armed) + brcmf_remove_interface(ifp, false); + } } =20 /** diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c b/d= rivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c index f6241fd..66f942f 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c @@ -2288,8 +2288,7 @@ int brcmf_p2p_del_vif(struct wiphy *wiphy, struct= wireless_dev *wdev) else err =3D 0; } - if (err) - brcmf_remove_interface(vif->ifp, true); + brcmf_remove_interface(vif->ifp, true); =20 brcmf_cfg80211_arm_vif_event(cfg, NULL); if (vif->wdev.iftype !=3D NL80211_IFTYPE_P2P_DEVICE) --=20 1.8.4.5