On Tue, Mar 28, 2017 at 7:01 PM, Andrey Smirnov
<andrew.smirnov@xxxxxxxxx> wrote:
> Convert serdev_device_write_buf's code to be able to transfer amount of
> data potentially exceeding "write room" at the moment of invocation.
>
> To support that, also add serdev_device_write_wakeup.
>
> Drivers wanting to use full extent of serdev_device_write
> functionality are expected to provide serdev_device_write_wakeup as a
> sole handler of .write_wakeup event or call it as a part of driver's
> custom .write_wakeup code.
>
> Drivers wanting to retain old serdev_device_write_buf behaviour can
> replace those call to calls to serdev_device_write with timeout of
> 0. Providing .write_wakeup handler in such case is optional.
Some indentation would be better if, for example, 0 will be kept on
previous line.
So, what I would see if no one objects is patch series of two:
1) introduction of new API
2) removing old one.
It will benefit for easier review and any potential code anthropologist.
> --- a/drivers/tty/serdev/core.c
> +++ b/drivers/tty/serdev/core.c
> @@ -116,17 +116,41 @@ void serdev_device_close(struct serdev_device *serdev)
> }
> EXPORT_SYMBOL_GPL(serdev_device_close);
>
> -int serdev_device_write_buf(struct serdev_device *serdev,
> - const unsigned char *buf, size_t count)
> +void serdev_device_write_wakeup(struct serdev_device *serdev)
> +{
> + complete(&serdev->write_comp);
> +}
> +EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
> +
> +int serdev_device_write(struct serdev_device *serdev,
> + const unsigned char *buf, size_t count,
> + unsigned long timeout)
> {
> struct serdev_controller *ctrl = serdev->ctrl;
> + int ret;
>
> - if (!ctrl || !ctrl->ops->write_buf)
> + if (!ctrl || !ctrl->ops->write_buf ||
> + (timeout && !serdev->ops->write_wakeup))
> return -EINVAL;
>
> - return ctrl->ops->write_buf(ctrl, buf, count);
> + mutex_lock(&serdev->write_lock);
> + do {
> + reinit_completion(&serdev->write_comp);
> +
> + ret = ctrl->ops->write_buf(ctrl, buf, count);
> + if (ret < 0)
> + break;
> +
> + buf += ret;
Extra white spaces.
> + count -= ret;
> +
> + } while (count &&
> + (timeout = wait_for_completion_timeout(&serdev->write_comp,
> + timeout)));
So, would it be better to support interrupts here and return a
corresponding error code to the user?
Besides that question, readability might be better if you use
temporary variable and pack above on one line:
unsigned long to = timeout;
} while (count && (to = ...(to)));
> + mutex_unlock(&serdev->write_lock);
> + return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
> }
> -EXPORT_SYMBOL_GPL(serdev_device_write_buf);
> +EXPORT_SYMBOL_GPL(serdev_device_write);
> + * @write_comp Completion used by serdev_device_write internally
Links to the functions are func()-like. Please check kernel doc howto:s.
> + * @write_lock Mutext used to esure exclusive access to the bus when
> + * writing data with serdev_device_write()
checkpatch.pl has integrated spellchecker AFAIU.
Moreover, can you try harder to make that description shorter?
> void serdev_device_write_flush(struct serdev_device *);
> int serdev_device_write_room(struct serdev_device *);
>
> +
> /*
> * serdev device driver functions
> */
This doesn't belong to the change.
--
With Best Regards,
Andy Shevchenko
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