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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=zMAKXCwpjk/M1ee/TFS2x2huVLNZMq4N2Rp0iTVZNjg=; b=lFCKrYUsBfNaUQkFG8OrT6AlwDY7VDvCVbEi5Rtgry1vo7OeYusLDHk4DXUrhQBZfx 3NXu/KvVsJK98f9mhv6WqE74h5Mjjquh1kQTTnLpjSN1YyGBKzTP38TYNIyCYGkaR7xX DBL4KzD4dvBf1yDYR5K0ssc2RQdNN77bKDT+WrMSeouN6Y98AWW/XnYxX2iG1iKSCvUw McbeC68Z+2rmmWpAljcu15XuYYJ5hvzSscZNgYZn5FtPmPcGUyZj6vFuMvm8GolUgP/Z O3lfiIIOr8bU3RcygS/vafCCzC9mXQGh9h/DiAGD3eFyqicxjqHGhG5tGgexZA2Sh3Q0 RHyQ== X-Gm-Message-State: AOAM533qanTxm/CiM6nFeppM4FtiwdG68/dP8XfAcMZKbLqo4KncS24w Ug5C5BndxtyuQfqDJ0gDvHkmL+2vLzNXcZnGIfN9MlZp X-Google-Smtp-Source: ABdhPJzwqUXgMfEogucuJJhDaPrfMMO3vaCECekOSQ+MevzxKBugSycI1HERJxqq6hKh4bMM7kxZVgtEm91kRu4KIEc= X-Received: by 2002:a37:9b91:: with SMTP id d139mr14214072qke.377.1596443190069; Mon, 03 Aug 2020 01:26:30 -0700 (PDT) MIME-Version: 1.0 References: <20200803065105.8997-1-yzc666@netease.com> <20200803081604.GC493272@kroah.com> In-Reply-To: <20200803081604.GC493272@kroah.com> From: Daniele Palmas Date: Mon, 3 Aug 2020 10:26:18 +0200 Message-ID: Subject: Re: [PATCH] qmi_wwan: support modify usbnet's rx_urb_size To: Greg KH Cc: yzc666@netease.com, =?UTF-8?Q?Bj=C3=B8rn_Mork?= , David Miller , kuba@kernel.org, netdev@vger.kernel.org, linux-usb , carl Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Greg, Il giorno lun 3 ago 2020 alle ore 10:18 Greg KH ha scritto: > > On Mon, Aug 03, 2020 at 02:51:05PM +0800, yzc666@netease.com wrote: > > From: carl > > > > When QMUX enabled, the 'dl-datagram-max-size' can be 4KB/16KB/31KB depend on QUALCOMM's chipsets. > > User can set 'dl-datagram-max-size' by 'QMI_WDA_SET_DATA_FORMAT'. > > The usbnet's rx_urb_size must lager than or equal to the 'dl-datagram-max-size'. > > This patch allow user to modify usbnet's rx_urb_size by next command. > > > > echo 4096 > /sys/class/net/wwan0/qmi/rx_urb_size > > > > Next commnds show how to set and query 'dl-datagram-max-size' by qmicli > > # qmicli -d /dev/cdc-wdm1 --wda-set-data-format="link-layer-protocol=raw-ip, ul-protocol=qmap, > > dl-protocol=qmap, dl-max-datagrams=32, dl-datagram-max-size=31744, ep-type=hsusb, ep-iface-number=4" > > [/dev/cdc-wdm1] Successfully set data format > > QoS flow header: no > > Link layer protocol: 'raw-ip' > > Uplink data aggregation protocol: 'qmap' > > Downlink data aggregation protocol: 'qmap' > > NDP signature: '0' > > Downlink data aggregation max datagrams: '10' > > Downlink data aggregation max size: '4096' > > > > # qmicli -d /dev/cdc-wdm1 --wda-get-data-format > > [/dev/cdc-wdm1] Successfully got data format > > QoS flow header: no > > Link layer protocol: 'raw-ip' > > Uplink data aggregation protocol: 'qmap' > > Downlink data aggregation protocol: 'qmap' > > NDP signature: '0' > > Downlink data aggregation max datagrams: '10' > > Downlink data aggregation max size: '4096' > > > > Signed-off-by: carl > > --- > > drivers/net/usb/qmi_wwan.c | 39 ++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 39 insertions(+) > > > > diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c > > index 07c42c0719f5b..8ea57fd99ae43 100644 > > --- a/drivers/net/usb/qmi_wwan.c > > +++ b/drivers/net/usb/qmi_wwan.c > > @@ -400,6 +400,44 @@ static ssize_t raw_ip_store(struct device *d, struct device_attribute *attr, co > > return ret; > > } > > > > +static ssize_t rx_urb_size_show(struct device *d, struct device_attribute *attr, char *buf) > > +{ > > + struct usbnet *dev = netdev_priv(to_net_dev(d)); > > + > > + return sprintf(buf, "%zd\n", dev->rx_urb_size); > > Why do you care about this? > > > +} > > + > > +static ssize_t rx_urb_size_store(struct device *d, struct device_attribute *attr, > > + const char *buf, size_t len) > > +{ > > + struct usbnet *dev = netdev_priv(to_net_dev(d)); > > + u32 rx_urb_size; > > + int ret; > > + > > + if (kstrtou32(buf, 0, &rx_urb_size)) > > + return -EINVAL; > > + > > + /* no change? */ > > + if (rx_urb_size == dev->rx_urb_size) > > + return len; > > + > > + if (!rtnl_trylock()) > > + return restart_syscall(); > > + > > + /* we don't want to modify a running netdev */ > > + if (netif_running(dev->net)) { > > + netdev_err(dev->net, "Cannot change a running device\n"); > > + ret = -EBUSY; > > + goto err; > > + } > > + > > + dev->rx_urb_size = rx_urb_size; > > + ret = len; > > +err: > > + rtnl_unlock(); > > + return ret; > > +} > > + > > static ssize_t add_mux_show(struct device *d, struct device_attribute *attr, char *buf) > > { > > struct net_device *dev = to_net_dev(d); > > @@ -505,6 +543,7 @@ static DEVICE_ATTR_RW(add_mux); > > static DEVICE_ATTR_RW(del_mux); > > > > static struct attribute *qmi_wwan_sysfs_attrs[] = { > > + &dev_attr_rx_urb_size.attr, > > You added a driver-specific sysfs file and did not document in in > Documentation/ABI? That's not ok, sorry, please fix up. > > Actually, no, this all should be done "automatically", do not change the > urb size on the fly. Change it at probe time based on the device you > are using, do not force userspace to "know" what to do here, as it will > not know that at all. > the problem with doing at probe time is that rx_urb_size is not fixed, but depends on the configuration done at the userspace level with QMI_WDA_SET_DATA_FORMAT, so the userspace knows that. Currently there's a workaround for setting rx_urb_size i.e. changing the network interface MTU: this is fine for most uses with qmap, but there's the limitation that certain values (multiple of the endpoint size) are not allowed. Thanks, Daniele > thanks, > > greg k-h