Return-path: Received: from mail-ob0-f179.google.com ([209.85.214.179]:34598 "EHLO mail-ob0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753228AbaCLNV7 convert rfc822-to-8bit (ORCPT ); Wed, 12 Mar 2014 09:21:59 -0400 Received: by mail-ob0-f179.google.com with SMTP id va2so9991822obc.38 for ; Wed, 12 Mar 2014 06:21:58 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1394629569-13798-4-git-send-email-luciano.coelho@intel.com> References: <1394629569-13798-1-git-send-email-luciano.coelho@intel.com> <1394629569-13798-4-git-send-email-luciano.coelho@intel.com> Date: Wed, 12 Mar 2014 14:21:58 +0100 Message-ID: (sfid-20140312_142209_229505_56D686ED) Subject: Re: [PATCH v7 3/4] mac80211: implement chanctx reservation From: Michal Kazior To: Luciano Coelho Cc: linux-wireless , Johannes Berg , sw@simonwunderlich.de, "Otcheretianski, Andrei" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12 March 2014 14:06, Luciano Coelho wrote: [...] > + if (old_ctx == ctx) { > + /* This is our own context, just change it */ > + ret = __ieee80211_vif_change_channel(sdata, old_ctx, > + &tmp_changed); > + if (ret) > + goto out; > + } else { > + if (sdata->vif.bss_conf.chandef.width != > + sdata->reserved_chandef.width) > + tmp_changed |= BSS_CHANGED_BANDWIDTH; > + > + sdata->vif.bss_conf.chandef = sdata->reserved_chandef; > + > + ret = ieee80211_assign_vif_chanctx(sdata, ctx); > + if (old_ctx->refcount == 0) > + ieee80211_free_chanctx(local, old_ctx); > + if (ret) { > + /* if assign fails refcount stays the same */ > + if (ctx->refcount == 0) > + ieee80211_free_chanctx(local, ctx); > + goto out; > + } > + > + *changed = tmp_changed; > + > + ieee80211_vif_copy_chanctx_to_vlans(sdata, false); Ah, you can't call it like that. This will deadlock because the function tries to grab chanctx_mtx but you're already holding it. You need to first split the vif_copy_chanctx() into 2 variants - with and without grabbing the chanctx_mtx. > + ieee80211_recalc_chanctx_chantype(local, ctx); > + ieee80211_recalc_smps_chanctx(local, ctx); > + ieee80211_recalc_radar_chanctx(local, ctx); > + ieee80211_recalc_chanctx_min_def(local, ctx); It seems you need to call these recalc* regardless what if() branch is taken so calling them in this branch is pointless, no? > + } > + > + *changed = tmp_changed; > + > + ieee80211_recalc_chanctx_chantype(local, ctx); > + ieee80211_recalc_smps_chanctx(local, ctx); > + ieee80211_recalc_radar_chanctx(local, ctx); > + ieee80211_recalc_chanctx_min_def(local, ctx); Michał