Re: [linux-nfc] [PATCH 1/8] NFC: NCI: Allow connection close with dev down

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 [off-list ref] wrote:

quoted

Hi Robert,

On Tue, Feb 24, 2015 at 12:01:45PM +0200, Robert Dolca wrote:

quoted

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 <redacted>
---
 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.