Messages in this thread | | | Date | Wed, 18 Nov 2015 11:32:18 +0200 | Subject | Re: [PATCH] usb: gadget: Add the console support for usb-to-serial port | From | Andy Shevchenko <> |
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On Wed, Nov 18, 2015 at 4:15 AM, Baolin Wang <baolin.wang@linaro.org> wrote: > On 17 November 2015 at 21:34, Andy Shevchenko <andy.shevchenko@gmail.com> wrote: >> On Mon, Nov 16, 2015 at 9:05 AM, Baolin Wang <baolin.wang@linaro.org> wrote: >>> It dose not work when we want to use the usb-to-serial port based >>> on one usb gadget as a console. Thus this patch adds the console >>> initialization to support this request. >>
>>> +#define GS_BUFFER_SIZE (4096) >> Redundant parens > OK. I'll remove it. > >>> +#define GS_CONSOLE_BUF_SIZE (2 * GS_BUFFER_SIZE) >>> + >>> +struct gscons_info { >>> + struct gs_port *port; >>> + struct tty_driver *tty_driver; >>> + struct work_struct work; >>> + int buf_tail; >>> + char buf[GS_CONSOLE_BUF_SIZE]; >> >> Can't be malloced once? > The 'gscons_info' structure is malloced once.
In state of high fragmentation is quite hard to find big memory chunks. I would split it to two allocations, though if maintainers are okay with your code, then I'm also okay.
>>> +static struct usb_request *gs_request_new(struct usb_ep *ep, int buffer_size) >>> +{ >>> + struct usb_request *req = usb_ep_alloc_request(ep, GFP_ATOMIC); >>> + >>> + if (!req) >> >> For sake of readability it's better to have assignment explicitly before 'if'. > > But I think it is very easy to understand the assignment here with > saving code lines.
It's not a function of couple of lines, so, for me makes sense to explicitly put the assignment here. Especially that one that does allocations (for pointer arithmetic I could agree to place the assignment in the definition block).
>>> +static void gs_complete_out(struct usb_ep *ep, struct usb_request *req) >>> +{ >>> + if (req->status != 0 && req->status != -ECONNRESET) >>> + return; >> >> Something missed here. Currently it's no-op. >> > > Yeah. I didn't realize what need to do in the callback here, so just > leave a callback without anything. But maybe something will be added > if there are some requirements in future.
if () ..
will be optimized away, why not to remove it?
>>> + port = ports[port_num].port; >>> + if (!port) { >>> + pr_err("%s: serial line [%d] not allocated.\n", >>> + __func__, port_num); >>> + return -ENODEV; >>> + } >>> + >>> + if (!port->port_usb) { >>> + pr_err("%s: no port usb.\n", __func__); >> >> Starting from here could it be dev_err and so on? > > There are no dev_err things and device things in this file, so pr_xxx > is more reasonable.
This is understandable, but if in case you have device in place why not to use its name?
>>> + pr_debug("%s: port[%d] console connect!\n", __func__, port_num); >> >> Dynamic debug will add function name if asked. > > Sorry, I didn't get your point, you mean print the function name is > redundant here?
Right.
Just pr_debug("port[%d] …", …);
-- With Best Regards, Andy Shevchenko
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