* [PATCH] tty: serdev: fix serdev_device_write return value
@ 2017-05-02 0:17 Rob Herring
2017-05-02 9:25 ` Johan Hovold
0 siblings, 1 reply; 5+ messages in thread
From: Rob Herring @ 2017-05-02 0:17 UTC (permalink / raw)
To: Greg Kroah-Hartman; +Cc: linux-serial, linux-kernel, Andrey Smirnov
Commit 6fe729c4bdae ("serdev: Add serdev_device_write subroutine")
provides a compatibility wrapper for the existing
serdev_device_write_buf, but it fails to return the number of bytes
written causing users to timeout.
Fixes: 6fe729c4bdae ("serdev: Add serdev_device_write subroutine")
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rob Herring <robh@kernel.org>
---
drivers/tty/serdev/core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index 433de5ea9b02..ccfe56355c4f 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -127,7 +127,7 @@ int serdev_device_write(struct serdev_device *serdev,
unsigned long timeout)
{
struct serdev_controller *ctrl = serdev->ctrl;
- int ret;
+ int ret, wr_cnt = 0;
if (!ctrl || !ctrl->ops->write_buf ||
(timeout && !serdev->ops->write_wakeup))
@@ -143,12 +143,13 @@ int serdev_device_write(struct serdev_device *serdev,
buf += ret;
count -= ret;
+ wr_cnt += ret;
} while (count &&
(timeout = wait_for_completion_timeout(&serdev->write_comp,
timeout)));
mutex_unlock(&serdev->write_lock);
- return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
+ return ret < 0 ? ret : (count ? -ETIMEDOUT : wr_cnt);
}
EXPORT_SYMBOL_GPL(serdev_device_write);
--
2.11.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] tty: serdev: fix serdev_device_write return value
2017-05-02 0:17 [PATCH] tty: serdev: fix serdev_device_write return value Rob Herring
@ 2017-05-02 9:25 ` Johan Hovold
2017-05-02 12:30 ` Rob Herring
2017-05-03 17:44 ` Andy Shevchenko
0 siblings, 2 replies; 5+ messages in thread
From: Johan Hovold @ 2017-05-02 9:25 UTC (permalink / raw)
To: Rob Herring
Cc: Greg Kroah-Hartman, linux-serial, linux-kernel, Andrey Smirnov
On Mon, May 01, 2017 at 07:17:14PM -0500, Rob Herring wrote:
> Commit 6fe729c4bdae ("serdev: Add serdev_device_write subroutine")
> provides a compatibility wrapper for the existing
> serdev_device_write_buf, but it fails to return the number of bytes
> written causing users to timeout.
So this would also be fixed for serdev_device_write_buf() by Stefan
Wahren's patch restoring that function implementation, but returning the
amount written is perhaps desirable also for blocking writes for
consistency reasons.
> Fixes: 6fe729c4bdae ("serdev: Add serdev_device_write subroutine")
> Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
> drivers/tty/serdev/core.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
> index 433de5ea9b02..ccfe56355c4f 100644
> --- a/drivers/tty/serdev/core.c
> +++ b/drivers/tty/serdev/core.c
> @@ -127,7 +127,7 @@ int serdev_device_write(struct serdev_device *serdev,
> unsigned long timeout)
> {
> struct serdev_controller *ctrl = serdev->ctrl;
> - int ret;
> + int ret, wr_cnt = 0;
>
> if (!ctrl || !ctrl->ops->write_buf ||
> (timeout && !serdev->ops->write_wakeup))
> @@ -143,12 +143,13 @@ int serdev_device_write(struct serdev_device *serdev,
>
> buf += ret;
> count -= ret;
> + wr_cnt += ret;
>
> } while (count &&
> (timeout = wait_for_completion_timeout(&serdev->write_comp,
> timeout)));
>
> mutex_unlock(&serdev->write_lock);
> - return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
> + return ret < 0 ? ret : (count ? -ETIMEDOUT : wr_cnt);
That's some nasty use of the ternary operator. Ditching it completely
would be more readable.
if (ret < 0)
return ret;
if (count)
return -ETIMEDOUT;
return wr_count;
and here wr_count is the value of count passed to the function (and
could just be stored on entry instead).
> }
> EXPORT_SYMBOL_GPL(serdev_device_write);
Thanks,
Johan
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tty: serdev: fix serdev_device_write return value
2017-05-02 9:25 ` Johan Hovold
@ 2017-05-02 12:30 ` Rob Herring
2017-05-03 17:44 ` Andy Shevchenko
1 sibling, 0 replies; 5+ messages in thread
From: Rob Herring @ 2017-05-02 12:30 UTC (permalink / raw)
To: Johan Hovold
Cc: Greg Kroah-Hartman, linux-serial, linux-kernel, Andrey Smirnov
On Tue, May 2, 2017 at 4:25 AM, Johan Hovold <johan@kernel.org> wrote:
> On Mon, May 01, 2017 at 07:17:14PM -0500, Rob Herring wrote:
>> Commit 6fe729c4bdae ("serdev: Add serdev_device_write subroutine")
>> provides a compatibility wrapper for the existing
>> serdev_device_write_buf, but it fails to return the number of bytes
>> written causing users to timeout.
>
> So this would also be fixed for serdev_device_write_buf() by Stefan
> Wahren's patch restoring that function implementation, but returning the
> amount written is perhaps desirable also for blocking writes for
> consistency reasons.
Yes, I saw it after I wrote this. We should apply both IMO.
>> Fixes: 6fe729c4bdae ("serdev: Add serdev_device_write subroutine")
>> Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Signed-off-by: Rob Herring <robh@kernel.org>
>> ---
>> drivers/tty/serdev/core.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
>> index 433de5ea9b02..ccfe56355c4f 100644
>> --- a/drivers/tty/serdev/core.c
>> +++ b/drivers/tty/serdev/core.c
>> @@ -127,7 +127,7 @@ int serdev_device_write(struct serdev_device *serdev,
>> unsigned long timeout)
>> {
>> struct serdev_controller *ctrl = serdev->ctrl;
>> - int ret;
>> + int ret, wr_cnt = 0;
>>
>> if (!ctrl || !ctrl->ops->write_buf ||
>> (timeout && !serdev->ops->write_wakeup))
>> @@ -143,12 +143,13 @@ int serdev_device_write(struct serdev_device *serdev,
>>
>> buf += ret;
>> count -= ret;
>> + wr_cnt += ret;
>>
>> } while (count &&
>> (timeout = wait_for_completion_timeout(&serdev->write_comp,
>> timeout)));
>>
>> mutex_unlock(&serdev->write_lock);
>> - return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
>> + return ret < 0 ? ret : (count ? -ETIMEDOUT : wr_cnt);
>
> That's some nasty use of the ternary operator. Ditching it completely
> would be more readable.
>
> if (ret < 0)
> return ret;
>
> if (count)
> return -ETIMEDOUT;
>
> return wr_count;
>
> and here wr_count is the value of count passed to the function (and
> could just be stored on entry instead).
Okay.
I'll wait for Greg to apply Stefan's patch and respin on top of it.
Rob
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tty: serdev: fix serdev_device_write return value
2017-05-02 9:25 ` Johan Hovold
2017-05-02 12:30 ` Rob Herring
@ 2017-05-03 17:44 ` Andy Shevchenko
2017-05-03 18:06 ` Greg Kroah-Hartman
1 sibling, 1 reply; 5+ messages in thread
From: Andy Shevchenko @ 2017-05-03 17:44 UTC (permalink / raw)
To: Johan Hovold
Cc: Rob Herring, Greg Kroah-Hartman, linux-serial, linux-kernel,
Andrey Smirnov
On Tue, May 2, 2017 at 12:25 PM, Johan Hovold <johan@kernel.org> wrote:
> On Mon, May 01, 2017 at 07:17:14PM -0500, Rob Herring wrote:
>> - return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
>> + return ret < 0 ? ret : (count ? -ETIMEDOUT : wr_cnt);
>
> That's some nasty use of the ternary operator. Ditching it completely
> would be more readable.
>
> if (ret < 0)
> return ret;
>
> if (count)
> return -ETIMEDOUT;
>
> return wr_count;
While I agree on the first part, I would go still with one ternary at the end:
return count ? -ETIMEDOUT : wr_count;
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tty: serdev: fix serdev_device_write return value
2017-05-03 17:44 ` Andy Shevchenko
@ 2017-05-03 18:06 ` Greg Kroah-Hartman
0 siblings, 0 replies; 5+ messages in thread
From: Greg Kroah-Hartman @ 2017-05-03 18:06 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Johan Hovold, Rob Herring, linux-serial, linux-kernel, Andrey Smirnov
On Wed, May 03, 2017 at 08:44:07PM +0300, Andy Shevchenko wrote:
> On Tue, May 2, 2017 at 12:25 PM, Johan Hovold <johan@kernel.org> wrote:
> > On Mon, May 01, 2017 at 07:17:14PM -0500, Rob Herring wrote:
>
> >> - return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
> >> + return ret < 0 ? ret : (count ? -ETIMEDOUT : wr_cnt);
> >
> > That's some nasty use of the ternary operator. Ditching it completely
> > would be more readable.
> >
> > if (ret < 0)
> > return ret;
> >
> > if (count)
> > return -ETIMEDOUT;
> >
> > return wr_count;
>
>
> While I agree on the first part, I would go still with one ternary at the end:
>
> return count ? -ETIMEDOUT : wr_count;
Ick, no, make it easy to read, we write code for developers first, the
compiler second. Ditching it completly is a good idea.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-05-03 18:06 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-05-02 0:17 [PATCH] tty: serdev: fix serdev_device_write return value Rob Herring
2017-05-02 9:25 ` Johan Hovold
2017-05-02 12:30 ` Rob Herring
2017-05-03 17:44 ` Andy Shevchenko
2017-05-03 18:06 ` Greg Kroah-Hartman
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.