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[PATCH] usb: misc: usbtest: remove redundant check on retval < 0

Started byColin King <colin.king@canonical.com>
First post2017-02-12 19:40 +0100
Last post2017-02-13 17:50 +0100
Articles 5 — 5 participants

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  [PATCH] usb: misc: usbtest: remove redundant check on retval < 0 Colin King <colin.king@canonical.com> - 2017-02-12 19:40 +0100
    Re: [PATCH] usb: misc: usbtest: remove redundant check on retval < 0 Peter Chen <hzpeterchen@gmail.com> - 2017-02-13 11:00 +0100
    Re: [PATCH] usb: misc: usbtest: remove redundant check on retval < 0 Felipe Balbi <felipe.balbi@linux.intel.com> - 2017-02-13 11:50 +0100
      Re: [PATCH] usb: misc: usbtest: remove redundant check on retval <  0 Alan Stern <stern@rowland.harvard.edu> - 2017-02-13 17:50 +0100
      Re: [PATCH] usb: misc: usbtest: remove redundant check on retval < 0 Colin Ian King <colin.king@canonical.com> - 2017-02-13 17:50 +0100

#1579260 — [PATCH] usb: misc: usbtest: remove redundant check on retval < 0

FromColin King <colin.king@canonical.com>
Date2017-02-12 19:40 +0100
Subject[PATCH] usb: misc: usbtest: remove redundant check on retval < 0
Message-ID<ta7e1-1hK-5@gated-at.bofh.it>
From: Colin Ian King <colin.king@canonical.com>

The check for retval being less than zero is always true since
retval equal to -EPIPE at that point.  Replace the existing
conditional with just return retval.

Detected with CoverityScan, CID#114349 ("Logically dead code")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/usb/misc/usbtest.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
index 3525626..17c0810 100644
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -992,7 +992,7 @@ static int ch9_postconfig(struct usbtest_dev *dev)
 				dev_err(&iface->dev,
 						"hs dev qualifier --> %d\n",
 						retval);
-				return (retval < 0) ? retval : -EDOM;
+				return retval;
 			}
 			/* usb2.0 but not high-speed capable; fine */
 		} else if (retval != sizeof(struct usb_qualifier_descriptor)) {
-- 
2.10.2

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#1579559

FromPeter Chen <hzpeterchen@gmail.com>
Date2017-02-13 11:00 +0100
Message-ID<talAm-1ZB-15@gated-at.bofh.it>
In reply to#1579260
On Sun, Feb 12, 2017 at 06:35:18PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> The check for retval being less than zero is always true since
> retval equal to -EPIPE at that point.  Replace the existing
> conditional with just return retval.
> 
> Detected with CoverityScan, CID#114349 ("Logically dead code")
> 
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/usb/misc/usbtest.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
> index 3525626..17c0810 100644
> --- a/drivers/usb/misc/usbtest.c
> +++ b/drivers/usb/misc/usbtest.c
> @@ -992,7 +992,7 @@ static int ch9_postconfig(struct usbtest_dev *dev)
>  				dev_err(&iface->dev,
>  						"hs dev qualifier --> %d\n",
>  						retval);
> -				return (retval < 0) ? retval : -EDOM;
> +				return retval;
>  			}
>  			/* usb2.0 but not high-speed capable; fine */
>  		} else if (retval != sizeof(struct usb_qualifier_descriptor)) {

Reviewed-by: Peter Chen <peter.chen@nxp.com>

-- 

Best Regards,
Peter Chen

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#1579594

FromFelipe Balbi <felipe.balbi@linux.intel.com>
Date2017-02-13 11:50 +0100
Message-ID<tammJ-2yB-3@gated-at.bofh.it>
In reply to#1579260

[Multipart message — attachments visible in raw view] — view raw

Hi,

Colin King <colin.king@canonical.com> writes:
> From: Colin Ian King <colin.king@canonical.com>
>
> The check for retval being less than zero is always true since
> retval equal to -EPIPE at that point.  Replace the existing
> conditional with just return retval.
>
> Detected with CoverityScan, CID#114349 ("Logically dead code")
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/usb/misc/usbtest.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
> index 3525626..17c0810 100644
> --- a/drivers/usb/misc/usbtest.c
> +++ b/drivers/usb/misc/usbtest.c
> @@ -992,7 +992,7 @@ static int ch9_postconfig(struct usbtest_dev *dev)
>  				dev_err(&iface->dev,
>  						"hs dev qualifier --> %d\n",
>  						retval);
> -				return (retval < 0) ? retval : -EDOM;
> +				return retval;

you're changing return value here, are you sure there's nothing else
depending on this error?

-- 
balbi

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#1579936 — Re: [PATCH] usb: misc: usbtest: remove redundant check on retval < 0

FromAlan Stern <stern@rowland.harvard.edu>
Date2017-02-13 17:50 +0100
SubjectRe: [PATCH] usb: misc: usbtest: remove redundant check on retval < 0
Message-ID<tarZ7-6el-1@gated-at.bofh.it>
In reply to#1579594
On Mon, 13 Feb 2017, Felipe Balbi wrote:

> Hi,
> 
> Colin King <colin.king@canonical.com> writes:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > The check for retval being less than zero is always true since
> > retval equal to -EPIPE at that point.  Replace the existing
> > conditional with just return retval.
> >
> > Detected with CoverityScan, CID#114349 ("Logically dead code")
> >
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/usb/misc/usbtest.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
> > index 3525626..17c0810 100644
> > --- a/drivers/usb/misc/usbtest.c
> > +++ b/drivers/usb/misc/usbtest.c
> > @@ -992,7 +992,7 @@ static int ch9_postconfig(struct usbtest_dev *dev)
> >  				dev_err(&iface->dev,
> >  						"hs dev qualifier --> %d\n",
> >  						retval);
> > -				return (retval < 0) ? retval : -EDOM;
> > +				return retval;
> 
> you're changing return value here, are you sure there's nothing else
> depending on this error?

I bet you didn't look at the original code.  :-)  Just before the start
of the patch there is:

		if (retval == -EPIPE) {
			...

So no, the patch does not change the return value.

Alan Stern

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#1579939

FromColin Ian King <colin.king@canonical.com>
Date2017-02-13 17:50 +0100
Message-ID<tarZ7-6el-9@gated-at.bofh.it>
In reply to#1579594

[Multipart message — attachments visible in raw view] — view raw

On 13/02/17 10:45, Felipe Balbi wrote:
> 
> Hi,
> 
> Colin King <colin.king@canonical.com> writes:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> The check for retval being less than zero is always true since
>> retval equal to -EPIPE at that point.  Replace the existing
>> conditional with just return retval.
>>
>> Detected with CoverityScan, CID#114349 ("Logically dead code")
>>
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>>  drivers/usb/misc/usbtest.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
>> index 3525626..17c0810 100644
>> --- a/drivers/usb/misc/usbtest.c
>> +++ b/drivers/usb/misc/usbtest.c
>> @@ -992,7 +992,7 @@ static int ch9_postconfig(struct usbtest_dev *dev)
>>  				dev_err(&iface->dev,
>>  						"hs dev qualifier --> %d\n",
>>  						retval);
>> -				return (retval < 0) ? retval : -EDOM;
>> +				return retval;
> 
> you're changing return value here, are you sure there's nothing else
> depending on this error?
> 
The code in the current state will never return -EDOM and will always
return retval, so this change actually makes no functional change, it
just removes a redundant check.  So it's not going to make a jot of
difference to the current behaver.

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