Return-path: Received: from mail-lb0-f171.google.com ([209.85.217.171]:33289 "EHLO mail-lb0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752509AbbH1OGB (ORCPT ); Fri, 28 Aug 2015 10:06:01 -0400 MIME-Version: 1.0 In-Reply-To: <20150524170747.GB15886@ribalta.ccr.corp.intel.com> References: <1424772112-27399-1-git-send-email-robert.dolca@intel.com> <1424772112-27399-2-git-send-email-robert.dolca@intel.com> <20150326002925.GA10954@ribalta.home> <20150524170747.GB15886@ribalta.ccr.corp.intel.com> From: Robert Dolca Date: Fri, 28 Aug 2015 17:05:39 +0300 Message-ID: (sfid-20150828_160628_000102_5750EB32) Subject: Re: [linux-nfc] [PATCH 1/8] NFC: NCI: Allow connection close with dev down To: Samuel Ortiz Cc: Robert Dolca , linux-nfc@lists.01.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, "linux-kernel@vger.kernel.org" , "David S. Miller" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Sun, May 24, 2015 at 8:07 PM, Samuel Ortiz wrote: > Hi Robert, > > On Tue, Mar 31, 2015 at 05:03:42PM +0300, Robert Dolca wrote: >> On Thu, Mar 26, 2015 at 2:29 AM, Samuel Ortiz wrote: >> > Hi Robert, >> > >> > On Tue, Feb 24, 2015 at 12:01:45PM +0200, Robert Dolca wrote: >> >> By calling __nci_request instead of nci_request allows the driver to use >> >> the function while initializing the device (setup stage) >> >> >> >> Signed-off-by: Robert Dolca >> >> --- >> >> net/nfc/nci/core.c | 2 +- >> >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> >> >> diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c >> >> index 9575a18..c4dd5d8 100644 >> >> --- a/net/nfc/nci/core.c >> >> +++ b/net/nfc/nci/core.c >> >> @@ -558,7 +558,7 @@ static void nci_core_conn_close_req(struct nci_dev *ndev, unsigned long opt) >> >> >> >> int nci_core_conn_close(struct nci_dev *ndev, u8 conn_id) >> >> { >> >> - return nci_request(ndev, nci_core_conn_close_req, conn_id, >> >> + return __nci_request(ndev, nci_core_conn_close_req, conn_id, >> >> msecs_to_jiffies(NCI_CMD_TIMEOUT)); >> > You're fixing your problem by removing the NCI request serialization and >> > removing the check for your device being UP. >> > I assume you need to open and close a proprietary connection from your >> > setup hook ? Then please extend nci_request() to check for both NCI_UP >> > and NCI_INIT. >> >> You are right, I am opening and closing a connection from the setup >> function. The setup is called by nci_open_device. At the beginning of >> nci_open_device, req_lock is being acquired and it is release at the >> end of the function. That means that when setup is being called >> req_lock is acuired. As you said I can modify nci_request to check for >> NCI_INIT but it tries to acquire req_lock and it can not succeed. > I see, I thought the issue was only about checking the NCI_* flags. > > As a short term solution, I propose you do the following: > > a) Export nci_core_conn_create_req, nci_core_conn_close_req and > __nci_request. > b) Call __nci_request() directly from your fdp_nci_close_conn() and > fdp_nci_create_conn() routines. > > The long term, scalable fix would be to implement and export an > __nci_send_cmd_sync() routine, that would transparently build an NCI > request and tail it to the ndev req skb queue, and put the caller on a > wait queue. The created request's response callback would then wake the > caller up. If nci_open_device would use another mutex instead of req_lock this wouldn't be necessary. I don't see any reason why nci_open_device should block the send queue. Of course, in nci_open_device all calls to __nci_request would have to be replaced with nci_request. Samuel, would that be an acceptable solution? Regards, Robert