From: Loic Poulain <loic.poulain@linaro.org>
To: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
kuba@kernel.org, davem@davemloft.net, johannes@sipsolutions.net,
ryazanov.s.a@gmail.com, m.chetan.kumar@intel.com,
chandrashekar.devegowda@intel.com, linuxwwan@intel.com,
chiranjeevi.rapolu@linux.intel.com, haijun.liu@mediatek.com,
amir.hanania@intel.com, andriy.shevchenko@linux.intel.com,
dinesh.sharma@intel.com, eliot.lee@intel.com,
mika.westerberg@linux.intel.com, moises.veleta@intel.com,
pierre-louis.bossart@intel.com,
muralidharan.sethuraman@intel.com,
Soumya.Prakash.Mishra@intel.com, sreehari.kancharla@intel.com,
suresh.nagaraj@intel.com
Subject: Re: [PATCH net-next v3 05/12] net: wwan: t7xx: Add AT and MBIM WWAN ports
Date: Tue, 7 Dec 2021 10:48:06 +0100 [thread overview]
Message-ID: <CAMZdPi9w6KyK2snaMEDL1go7+McExgs+Vm+eSp=K5yugDcFQJA@mail.gmail.com> (raw)
In-Reply-To: <20211207024711.2765-6-ricardo.martinez@linux.intel.com>
Hi Ricardo,
Overall, it looks good, but:
On Tue, 7 Dec 2021 at 03:48, Ricardo Martinez
<ricardo.martinez@linux.intel.com> wrote:
>
> From: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
>
> Adds AT and MBIM ports to the port proxy infrastructure.
> The initialization method is responsible for creating the corresponding
> ports using the WWAN framework infrastructure. The implemented WWAN port
> operations are start, stop, and TX.
>
> Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
> Co-developed-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
> Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
> ---
> drivers/net/wwan/t7xx/Makefile | 1 +
> drivers/net/wwan/t7xx/t7xx_port_proxy.c | 24 +++
> drivers/net/wwan/t7xx/t7xx_port_proxy.h | 1 +
> drivers/net/wwan/t7xx/t7xx_port_wwan.c | 258 ++++++++++++++++++++++++
> 4 files changed, 284 insertions(+)
> create mode 100644 drivers/net/wwan/t7xx/t7xx_port_wwan.c
>
[...]
> +static int t7xx_port_ctrl_tx(struct wwan_port *port, struct sk_buff *skb)
> +{
> + struct t7xx_port *port_private = wwan_port_get_drvdata(port);
> + size_t actual_count = 0, alloc_size = 0, txq_mtu = 0;
> + struct t7xx_port_static *port_static;
> + int i, multi_packet = 1, ret = 0;
> + struct sk_buff *skb_ccci = NULL;
> + struct t7xx_fsm_ctl *ctl;
> + enum md_state md_state;
> + unsigned int count;
> + bool port_multi;
> +
> + count = skb->len;
> + if (!count)
> + return -EINVAL;
> +
> + port_static = port_private->port_static;
> + ctl = port_private->t7xx_dev->md->fsm_ctl;
> + md_state = t7xx_fsm_get_md_state(ctl);
> + if (md_state == MD_STATE_WAITING_FOR_HS1 || md_state == MD_STATE_WAITING_FOR_HS2) {
> + dev_warn(port_private->dev, "Cannot write to %s port when md_state=%d\n",
> + port_static->name, md_state);
> + return -ENODEV;
> + }
> +
> + txq_mtu = CLDMA_TXQ_MTU;
> +
> + if (port_private->flags & PORT_F_USER_HEADER) {
> + if (port_private->flags & PORT_F_USER_HEADER && count > txq_mtu) {
> + dev_err(port_private->dev, "Packet %u larger than MTU on %s port\n",
> + count, port_static->name);
> + return -ENOMEM;
> + }
> +
> + alloc_size = min_t(size_t, txq_mtu, count);
> + actual_count = alloc_size;
> + } else {
> + alloc_size = min_t(size_t, txq_mtu, count + CCCI_H_ELEN);
> + actual_count = alloc_size - CCCI_H_ELEN;
> + port_multi = t7xx_port_wwan_multipkt_capable(port_static);
> + if ((count + CCCI_H_ELEN > txq_mtu) && port_multi)
> + multi_packet = DIV_ROUND_UP(count, txq_mtu - CCCI_H_ELEN);
> + }
> +
> + for (i = 0; i < multi_packet; i++) {
> + struct ccci_header *ccci_h = NULL;
> +
> + if (multi_packet > 1 && multi_packet == i + 1) {
> + actual_count = count % (txq_mtu - CCCI_H_ELEN);
> + alloc_size = actual_count + CCCI_H_ELEN;
> + }
> +
> + skb_ccci = __dev_alloc_skb(alloc_size, GFP_KERNEL);
> + if (!skb_ccci)
> + return -ENOMEM;
> +
> + ccci_h = skb_put(skb_ccci, CCCI_H_LEN);
> + ccci_h->packet_header = 0;
> + ccci_h->packet_len = cpu_to_le32(actual_count + CCCI_H_LEN);
> + ccci_h->status &= cpu_to_le32(~HDR_FLD_CHN);
> + ccci_h->status |= cpu_to_le32(FIELD_PREP(HDR_FLD_CHN, port_static->tx_ch));
> + ccci_h->ex_msg = 0;
> +
> + memcpy(skb_put(skb_ccci, actual_count), skb->data + i * (txq_mtu - CCCI_H_ELEN),
> + actual_count);
> +
> + t7xx_port_proxy_set_seq_num(port_private, ccci_h);
> +
> + ret = t7xx_port_send_skb_to_md(port_private, skb_ccci, true);
> + if (ret)
> + goto err_free_skb;
> +
> + port_private->seq_nums[MTK_TX]++;
> +
> + if (multi_packet == 1)
> + return actual_count;
> + else if (multi_packet == i + 1)
> + return count;
wwan port tx ops is supposed to return 0 on success, and release the
processed skb. In your case it works because wwan core does:
ret = wwan_port_op_tx(port, skb, !!(filp->f_flags & O_NONBLOCK));
if (ret) {
kfree_skb(skb);
return ret;
}
So returning a positive value here (count) makes the core enter the
error case, release the skb for you and return your count value to
write fops. Eventually, you land on your feet, but it's not what was
expected from tx ops. You should simply return 0 on success and
release the skb. Alternatively, if you think partial TX is something
we need, it should be somewhat documented in the wwan_port_fops_write
function or tx_ops definition.
Regards,
Loic
next prev parent reply other threads:[~2021-12-07 9:36 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-07 2:46 [PATCH net-next v3 00/12] net: wwan: t7xx: PCIe driver for MediaTek M.2 modem Ricardo Martinez
2021-12-07 2:47 ` [PATCH net-next v3 01/12] net: wwan: t7xx: Add control DMA interface Ricardo Martinez
2021-12-07 17:11 ` Jakub Kicinski
2021-12-16 11:08 ` Ilpo Järvinen
2022-01-12 4:55 ` Martinez, Ricardo
2022-01-12 11:40 ` Andy Shevchenko
2022-01-12 14:24 ` Ilpo Järvinen
2022-01-12 16:20 ` Andy Shevchenko
2022-01-12 18:16 ` Ilpo Järvinen
2022-01-12 19:03 ` Martinez, Ricardo
2022-01-12 19:24 ` Ilpo Järvinen
2022-01-12 20:08 ` Martinez, Ricardo
2022-01-13 18:31 ` Ilpo Järvinen
2021-12-07 2:47 ` [PATCH net-next v3 02/12] net: wwan: t7xx: Add core components Ricardo Martinez
2021-12-16 11:55 ` Ilpo Järvinen
2022-01-12 21:58 ` Martinez, Ricardo
2021-12-07 2:47 ` [PATCH net-next v3 03/12] net: wwan: t7xx: Add port proxy infrastructure Ricardo Martinez
2021-12-16 12:17 ` Ilpo Järvinen
2021-12-07 2:47 ` [PATCH net-next v3 04/12] net: wwan: t7xx: Add control port Ricardo Martinez
2021-12-16 13:44 ` Ilpo Järvinen
2021-12-07 2:47 ` [PATCH net-next v3 05/12] net: wwan: t7xx: Add AT and MBIM WWAN ports Ricardo Martinez
2021-12-07 9:48 ` Loic Poulain [this message]
2021-12-16 12:25 ` Ilpo Järvinen
2021-12-16 12:59 ` Andy Shevchenko
2021-12-07 2:47 ` [PATCH net-next v3 06/12] net: wwan: t7xx: Data path HW layer Ricardo Martinez
2021-12-07 11:59 ` Andy Shevchenko
2021-12-07 12:04 ` Andy Shevchenko
2021-12-07 2:47 ` [PATCH net-next v3 07/12] net: wwan: t7xx: Add data path interface Ricardo Martinez
2021-12-16 13:30 ` Ilpo Järvinen
2022-01-12 23:27 ` Martinez, Ricardo
2021-12-07 2:47 ` [PATCH net-next v3 08/12] net: wwan: t7xx: Add WWAN network interface Ricardo Martinez
2021-12-07 2:47 ` [PATCH net-next v3 09/12] net: wwan: t7xx: Introduce power management support Ricardo Martinez
2021-12-07 2:47 ` [PATCH net-next v3 10/12] net: wwan: t7xx: Runtime PM Ricardo Martinez
2021-12-07 2:47 ` [PATCH net-next v3 11/12] net: wwan: t7xx: Device deep sleep lock/unlock Ricardo Martinez
2021-12-07 2:47 ` [PATCH net-next v3 12/12] net: wwan: t7xx: Add maintainers and documentation Ricardo Martinez
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