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From: Samuel Ortiz <sameo@linux.intel.com>
To: Robert Dolca <robert.dolca@gmail.com>
Cc: Robert Dolca <robert.dolca@intel.com>,
	linux-nfc@ml01.01.org, netdev@vger.kernel.org,
	linux-wireless@vger.kernel.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: [linux-nfc] [PATCH 1/8] NFC: NCI: Allow connection close with dev down
Date: Sun, 24 May 2015 19:07:47 +0200	[thread overview]
Message-ID: <20150524170747.GB15886@ribalta.ccr.corp.intel.com> (raw)
In-Reply-To: <CAFPB+Yc-+1s4Y1iWnnCHWjnk=U5Rq-6Wq-idtakCxju8pvYi4Q@mail.gmail.com>

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 <sameo@linux.intel.com> 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 <robert.dolca@intel.com>
> >> ---
> >>  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.

Cheers,
Samuel.

  reply	other threads:[~2015-05-24 17:07 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-24 10:01 [PATCH 0/8] Adds Intel FieldsPeak NFC solution driver Robert Dolca
2015-02-24 10:01 ` [PATCH 1/8] NFC: NCI: Allow connection close with dev down Robert Dolca
2015-03-26  0:29   ` Samuel Ortiz
2015-03-31 14:03     ` [linux-nfc] " Robert Dolca
2015-05-24 17:07       ` Samuel Ortiz [this message]
2015-08-28 14:05         ` Robert Dolca
2015-02-24 10:01 ` [PATCH 2/8] NFC: NCI: Exporting NFC command and data send API Robert Dolca
2015-02-24 10:01 ` [PATCH 3/8] NFC: NCI: Adds NCI init and reset API for drivers Robert Dolca
2015-03-26  0:29   ` Samuel Ortiz
2015-03-31 14:05     ` [linux-nfc] " Robert Dolca
2015-05-24 17:07       ` Samuel Ortiz
2015-02-24 10:01 ` [PATCH 4/8] NFC: NCI: Add a special nci_request for driver Robert Dolca
2015-03-26  0:29   ` Samuel Ortiz
2015-03-31 14:07     ` [linux-nfc] " Robert Dolca
2015-02-24 10:01 ` [PATCH 5/8] NFC: NCI: Don't call setup if previous NCI request failed Robert Dolca
2015-03-26  0:29   ` Samuel Ortiz
2015-02-24 10:01 ` [PATCH 6/8] NFC: NCI: Add function to get max packet size for conn Robert Dolca
2015-02-24 10:01 ` [PATCH 7/8] NFC: NCI: Adds a way to get the new connection ID Robert Dolca
2015-02-24 10:01 ` [PATCH 8/8] NFC: Add Intel FieldsPeak NFC solution driver Robert Dolca
2015-02-24 10:33   ` Johannes Berg
2015-02-24 10:46     ` Robert Dolca
2015-03-26  0:30   ` Samuel Ortiz
2015-04-01 15:35     ` [linux-nfc] " Robert Dolca
2015-05-24 17:08       ` Samuel Ortiz
2015-03-26 11:20   ` Samuel Ortiz
2015-03-26 13:45   ` Mika Westerberg
2015-02-24 16:14 ` [PATCH 0/8] Adds " Greg Rose
2015-02-24 16:25   ` Daniel Baluta
2015-02-24 16:27     ` Greg Rose

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