Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 3/3] tty: n_gsm: Fix waking up upper tty layer when room
 available
To:     Gregory CLEMENT <gregory.clement@bootlin.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     Thomas Petazzoni <thomas.petazzoni@bootlin.com>
References: <20200430113433.2162886-1-gregory.clement@bootlin.com>
 <20200430113433.2162886-5-gregory.clement@bootlin.com>
From:   Jiri Slaby <jslaby@suse.cz>
Autocrypt: addr=jslaby@suse.cz; prefer-encrypt=mutual; keydata=
 mQINBE6S54YBEACzzjLwDUbU5elY4GTg/NdotjA0jyyJtYI86wdKraekbNE0bC4zV+ryvH4j
 rrcDwGs6tFVrAHvdHeIdI07s1iIx5R/ndcHwt4fvI8CL5PzPmn5J+h0WERR5rFprRh6axhOk
 rSD5CwQl19fm4AJCS6A9GJtOoiLpWn2/IbogPc71jQVrupZYYx51rAaHZ0D2KYK/uhfc6neJ
 i0WqPlbtIlIrpvWxckucNu6ZwXjFY0f3qIRg3Vqh5QxPkojGsq9tXVFVLEkSVz6FoqCHrUTx
 wr+aw6qqQVgvT/McQtsI0S66uIkQjzPUrgAEtWUv76rM4ekqL9stHyvTGw0Fjsualwb0Gwdx
 ReTZzMgheAyoy/umIOKrSEpWouVoBt5FFSZUyjuDdlPPYyPav+hpI6ggmCTld3u2hyiHji2H
 cDpcLM2LMhlHBipu80s9anNeZhCANDhbC5E+NZmuwgzHBcan8WC7xsPXPaiZSIm7TKaVoOcL
 9tE5aN3jQmIlrT7ZUX52Ff/hSdx/JKDP3YMNtt4B0cH6ejIjtqTd+Ge8sSttsnNM0CQUkXps
 w98jwz+Lxw/bKMr3NSnnFpUZaxwji3BC9vYyxKMAwNelBCHEgS/OAa3EJoTfuYOK6wT6nadm
 YqYjwYbZE5V/SwzMbpWu7Jwlvuwyfo5mh7w5iMfnZE+vHFwp/wARAQABtBtKaXJpIFNsYWJ5
 IDxqc2xhYnlAc3VzZS5jej6JAjgEEwECACIFAk6S6NgCGwMGCwkIBwMCBhUIAgkKCwQWAgMB
 Ah4BAheAAAoJEL0lsQQGtHBJgDsP/j9wh0vzWXsOPO3rDpHjeC3BT5DKwjVN/KtP7uZttlkB
 duReCYMTZGzSrmK27QhCflZ7Tw0Naq4FtmQSH8dkqVFugirhlCOGSnDYiZAAubjTrNLTqf7e
 5poQxE8mmniH/Asg4KufD9bpxSIi7gYIzaY3hqvYbVF1vYwaMTujojlixvesf0AFlE4x8WKs
 wpk43fmo0ZLcwObTnC3Hl1JBsPujCVY8t4E7zmLm7kOB+8EHaHiRZ4fFDWweuTzRDIJtVmrH
 LWvRDAYg+IH3SoxtdJe28xD9KoJw4jOX1URuzIU6dklQAnsKVqxz/rpp1+UVV6Ky6OBEFuoR
 613qxHCFuPbkRdpKmHyE0UzmniJgMif3v0zm/+1A/VIxpyN74cgwxjhxhj/XZWN/LnFuER1W
 zTHcwaQNjq/I62AiPec5KgxtDeV+VllpKmFOtJ194nm9QM9oDSRBMzrG/2AY/6GgOdZ0+qe+
 4BpXyt8TmqkWHIsVpE7I5zVDgKE/YTyhDuqYUaWMoI19bUlBBUQfdgdgSKRMJX4vE72dl8BZ
 +/ONKWECTQ0hYntShkmdczcUEsWjtIwZvFOqgGDbev46skyakWyod6vSbOJtEHmEq04NegUD
 al3W7Y/FKSO8NqcfrsRNFWHZ3bZ2Q5X0tR6fc6gnZkNEtOm5fcWLY+NVz4HLaKrJuQINBE6S
 54YBEADPnA1iy/lr3PXC4QNjl2f4DJruzW2Co37YdVMjrgXeXpiDvneEXxTNNlxUyLeDMcIQ
 K8obCkEHAOIkDZXZG8nr4mKzyloy040V0+XA9paVs6/ice5l+yJ1eSTs9UKvj/pyVmCAY1Co
 SNN7sfPaefAmIpduGacp9heXF+1Pop2PJSSAcCzwZ3PWdAJ/w1Z1Dg/tMCHGFZ2QCg4iFzg5
 Bqk4N34WcG24vigIbRzxTNnxsNlU1H+tiB81fngUp2pszzgXNV7CWCkaNxRzXi7kvH+MFHu2
 1m/TuujzxSv0ZHqjV+mpJBQX/VX62da0xCgMidrqn9RCNaJWJxDZOPtNCAWvgWrxkPFFvXRl
 t52z637jleVFL257EkMI+u6UnawUKopa+Tf+R/c+1Qg0NHYbiTbbw0pU39olBQaoJN7JpZ99
 T1GIlT6zD9FeI2tIvarTv0wdNa0308l00bas+d6juXRrGIpYiTuWlJofLMFaaLYCuP+e4d8x
 rGlzvTxoJ5wHanilSE2hUy2NSEoPj7W+CqJYojo6wTJkFEiVbZFFzKwjAnrjwxh6O9/V3O+Z
 XB5RrjN8hAf/4bSo8qa2y3i39cuMT8k3nhec4P9M7UWTSmYnIBJsclDQRx5wSh0Mc9Y/psx9
 B42WbV4xrtiiydfBtO6tH6c9mT5Ng+d1sN/VTSPyfQARAQABiQIfBBgBAgAJBQJOkueGAhsM
 AAoJEL0lsQQGtHBJN7UQAIDvgxaW8iGuEZZ36XFtewH56WYvVUefs6+Pep9ox/9ZXcETv0vk
 DUgPKnQAajG/ViOATWqADYHINAEuNvTKtLWmlipAI5JBgE+5g9UOT4i69OmP/is3a/dHlFZ3
 qjNk1EEGyvioeycJhla0RjakKw5PoETbypxsBTXk5EyrSdD/I2Hez9YGW/RcI/WC8Y4Z/7FS
 ITZhASwaCOzy/vX2yC6iTx4AMFt+a6Z6uH/xGE8pG5NbGtd02r+m7SfuEDoG3Hs1iMGecPyV
 XxCVvSV6dwRQFc0UOZ1a6ywwCWfGOYqFnJvfSbUiCMV8bfRSWhnNQYLIuSv/nckyi8CzCYIg
 c21cfBvnwiSfWLZTTj1oWyj5a0PPgGOdgGoIvVjYXul3yXYeYOqbYjiC5t99JpEeIFupxIGV
 ciMk6t3pDrq7n7Vi/faqT+c4vnjazJi0UMfYnnAzYBa9+NkfW0w5W9Uy7kW/v7SffH/2yFiK
 9HKkJqkN9xYEYaxtfl5pelF8idoxMZpTvCZY7jhnl2IemZCBMs6s338wS12Qro5WEAxV6cjD
 VSdmcD5l9plhKGLmgVNCTe8DPv81oDn9s0cIRLg9wNnDtj8aIiH8lBHwfUkpn32iv0uMV6Ae
 sLxhDWfOR4N+wu1gzXWgLel4drkCJcuYK5IL1qaZDcuGR8RPo3jbFO7Y
Message-ID: <dee67599-a3bf-3904-e26b-4a02f36cf67f@suse.cz>
Date:   Mon, 4 May 2020 08:30:56 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.6.0
MIME-Version: 1.0
In-Reply-To: <20200430113433.2162886-5-gregory.clement@bootlin.com>
Content-Type: text/plain; charset=iso-8859-2
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 30. 04. 20, 13:34, Gregory CLEMENT wrote:
> Warn the upper layer when n_gms is ready to receive data
> again. Without this the associated virtual tty remain blocked

s/remain/&s/

> indefinitely.
> 
> Fixes: 96fd7ce58ffb ("TTY: create drivers/tty and move the tty core files there")

This looks invalid. Did you use git blame? Or git log, with --follow -M?

> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
> ---
>  drivers/tty/n_gsm.c | 33 +++++++++++++++++++++++++++++----
>  1 file changed, 29 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
> index 58950b33e5ac..4ff2b981aa7e 100644
> --- a/drivers/tty/n_gsm.c
> +++ b/drivers/tty/n_gsm.c
> @@ -665,10 +665,12 @@ static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
>   *	FIXME: lock against link layer control transmissions
>   */
>  
> -static void gsm_data_kick(struct gsm_mux *gsm)
> +static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
>  {
>  	struct gsm_msg *msg, *nmsg;
>  	int len;
> +	struct tty_struct *tty_dlci = NULL;
> +
>  
>  	list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
>  		if (gsm->constipated && msg->addr)
> @@ -697,6 +699,29 @@ static void gsm_data_kick(struct gsm_mux *gsm)
>  
>  		list_del(&msg->list);
>  		kfree(msg);
> +
> +		if (dlci) {
> +			tty_dlci = tty_port_tty_get(&dlci->port);
> +			if (tty_dlci)
> +				tty_wakeup(tty_dlci);

No tty_port_put looks wrong to me?

Why not to use tty_port_tty_wakeup?

> +		} else {
> +			int i = 0;
> +
> +			while (i < NUM_DLCI) {

Hmm, feels like 'for' loop fits better here.

> +				struct gsm_dlci *dlci;
> +
> +				dlci = gsm->dlci[i];
> +				if (dlci == NULL) {
> +					i++;
> +					continue;
> +				}
> +
> +				tty_dlci = tty_port_tty_get(&dlci->port);
> +				if (tty_dlci)
> +					tty_wakeup(tty_dlci);

Dtto

> +				i++;
> +			}
> +		}
>  	}
>  }
>  
> @@ -748,7 +773,7 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
>  	/* Add to the actual output queue */
>  	list_add_tail(&msg->list, &gsm->tx_list);
>  	gsm->tx_bytes += msg->len;
> -	gsm_data_kick(gsm);
> +	gsm_data_kick(gsm, dlci);

thanks,
-- 
js
suse labs