From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail29.static.mailgun.info ([104.130.122.29]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jyr6H-0004Cl-O7 for ath10k@lists.infradead.org; Fri, 24 Jul 2020 06:22:38 +0000 From: "Rakesh Pillai" References: <1595351666-28193-1-git-send-email-pillair@codeaurora.org> <1595351666-28193-2-git-send-email-pillair@codeaurora.org> <0dbdef912f9d61521011f638200fd451a3530568.camel@sipsolutions.net> <003201d6611e$c54a1c90$4fde55b0$@codeaurora.org> In-Reply-To: Subject: RE: [RFC 1/7] mac80211: Add check for napi handle before WARN_ON Date: Fri, 24 Jul 2020 11:51:12 +0530 Message-ID: <000401d66182$a3d97ab0$eb8c7010$@codeaurora.org> MIME-Version: 1.0 Content-Language: en-us List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "ath10k" Errors-To: ath10k-bounces+kvalo=adurom.com@lists.infradead.org To: 'Johannes Berg' , ath10k@lists.infradead.org Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, evgreen@chromium.org, dianders@chromium.org, kuba@kernel.org, davem@davemloft.net, kvalo@codeaurora.org > -----Original Message----- > From: Johannes Berg > Sent: Friday, July 24, 2020 1:37 AM > To: Rakesh Pillai ; ath10k@lists.infradead.org > Cc: linux-wireless@vger.kernel.org; linux-kernel@vger.kernel.org; > kvalo@codeaurora.org; davem@davemloft.net; kuba@kernel.org; > netdev@vger.kernel.org; dianders@chromium.org; evgreen@chromium.org > Subject: Re: [RFC 1/7] mac80211: Add check for napi handle before > WARN_ON > > On Thu, 2020-07-23 at 23:56 +0530, Rakesh Pillai wrote: > > > > > - WARN_ON_ONCE(softirq_count() == 0); > > > > + WARN_ON_ONCE(napi && softirq_count() == 0); > > > > > > FWIW, I'm pretty sure this is incorrect - we make assumptions on > > > softirqs being disabled in mac80211 for serialization and in place of > > > some locking, I believe. > > > > > > > I checked this, but let me double confirm. > > But after this change, no packet is submitted from driver in a softirq > context. > > So ideally this should take care of serialization. > > I'd guess that we have some reliance on BHs already being disabled, for > things like u64 sync updates, or whatnot. I mean, we did "rx_ni()" for a > reason ... Maybe lockdep can help catch some of the issues. > > But couldn't you be in a thread and have BHs disabled too? This would ideally beat the purpose and possibly hurt the other subsystems running on the same core. > > johannes _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k