[PATCH v2 0/2] staging: rtl8192u: cleanup of ternary and if else statements

[PATCH v2 0/2] staging: rtl8192u: cleanup of ternary and if else statements

[Rebecca Mckeever]

These patches replace ternary and if else statements with
more readable statements. Found with minmax coccinelle script.

---
v1 -> v2:
* Patch 1: "staging: rtl8192u: replace ternary statement with if and
* assignment"
  * replaced max macro with an if statement followed by an assignment

* Patch 2: "staging: rtl8192u: use min_t/max_t macros instead of if
* else"
  * changed the type argument in min_t and max_t from u8 to u32
---

Rebecca Mckeever (2):
  staging: rtl8192u: replace ternary statement with if and assignment
  staging: rtl8192u: use min_t/max_t macros instead of if else

 drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c   |  4 +++-
 drivers/staging/rtl8192u/ieee80211/rtl819x_HTProc.c | 13 +++++--------
 2 files changed, 8 insertions(+), 9 deletions(-)

-- 
2.32.0

[PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Rebecca Mckeever]

Replace ternary statement with an if statement followed by an assignment
to increase readability and make error handling more obvious.
Found with minmax coccinelle script.

Signed-off-by: Rebecca Mckeever <remckee0@gmail.com>
---
 drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
index 78cc8f357bbc..9885917b9199 100644
--- a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
+++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
@@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
 		return 0;
 	}
 	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
-	erq->length = (len >= 0 ? len : 0);
+	if (len < 0)
+		len = 0;
+	erq->length = len;
 
 	erq->flags |= IW_ENCODE_ENABLED;
 
-- 
2.32.0

Re: [PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Julia Lawall]

On Thu, 7 Apr 2022, Rebecca Mckeever wrote:

> Replace ternary statement with an if statement followed by an assignment
> to increase readability and make error handling more obvious.
> Found with minmax coccinelle script.
>
> Signed-off-by: Rebecca Mckeever <remckee0@gmail.com>
> ---
>  drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> index 78cc8f357bbc..9885917b9199 100644
> --- a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> +++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> @@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
>  		return 0;
>  	}
>  	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
> -	erq->length = (len >= 0 ? len : 0);
> +	if (len < 0)
> +		len = 0;
> +	erq->length = len;

Maybe you could use max here?

julia

>
>  	erq->flags |= IW_ENCODE_ENABLED;
>
> --
> 2.32.0
>
>
>

Re: [PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Greg Kroah-Hartman]

On Fri, Apr 08, 2022 at 06:15:14AM +0200, Julia Lawall wrote:
> 
> 
> On Thu, 7 Apr 2022, Rebecca Mckeever wrote:
> 
> > Replace ternary statement with an if statement followed by an assignment
> > to increase readability and make error handling more obvious.
> > Found with minmax coccinelle script.
> >
> > Signed-off-by: Rebecca Mckeever <remckee0@gmail.com>
> > ---
> >  drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > index 78cc8f357bbc..9885917b9199 100644
> > --- a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > +++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > @@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
> >  		return 0;
> >  	}
> >  	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
> > -	erq->length = (len >= 0 ? len : 0);
> > +	if (len < 0)
> > +		len = 0;
> > +	erq->length = len;
> 
> Maybe you could use max here?

Dan said to not do this on based on the first submission :)

Re: [PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Dan Carpenter]

On Fri, Apr 08, 2022 at 06:15:14AM +0200, Julia Lawall wrote:
> On Thu, 7 Apr 2022, Rebecca Mckeever wrote:
> 
> > Replace ternary statement with an if statement followed by an assignment
> > to increase readability and make error handling more obvious.
> > Found with minmax coccinelle script.
> >
> > Signed-off-by: Rebecca Mckeever <remckee0@gmail.com>
> > ---
> >  drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > index 78cc8f357bbc..9885917b9199 100644
> > --- a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > +++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > @@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
> >  		return 0;
> >  	}
> >  	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
> > -	erq->length = (len >= 0 ? len : 0);
> > +	if (len < 0)
> > +		len = 0;
> > +	erq->length = len;
> 
> Maybe you could use max here?

Initially Rebecca did use max() but I NAKed it.  It's really not less
readable.  Better to handle the error explicitly.  Keep the error path
indented two tabs.  Separate from the success path.

regards,
dan carpenter

Re: [PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Joe Perches]

On Fri, 2022-04-08 at 08:57 +0300, Dan Carpenter wrote:
> On Fri, Apr 08, 2022 at 06:15:14AM +0200, Julia Lawall wrote:
> > On Thu, 7 Apr 2022, Rebecca Mckeever wrote:
> > 
> > > Replace ternary statement with an if statement followed by an assignment
> > > to increase readability and make error handling more obvious.
> > > Found with minmax coccinelle script.
[]
> > > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
[]
> > > @@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
> > >  		return 0;
> > >  	}
> > >  	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
> > > -	erq->length = (len >= 0 ? len : 0);
> > > +	if (len < 0)
> > > +		len = 0;
> > > +	erq->length = len;
> > 
> > Maybe you could use max here?
> 
> Initially Rebecca did use max() but I NAKed it.  It's really not less
> readable.  Better to handle the error explicitly.  Keep the error path
> indented two tabs.  Separate from the success path.

A comment would be useful as it's not obvious it's an 'error' path.
One has to read all 3 get_key functions to determine that.

Re: [PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Dan Carpenter]

On Thu, Apr 07, 2022 at 11:14:51PM -0700, Joe Perches wrote:
> On Fri, 2022-04-08 at 08:57 +0300, Dan Carpenter wrote:
> > On Fri, Apr 08, 2022 at 06:15:14AM +0200, Julia Lawall wrote:
> > > On Thu, 7 Apr 2022, Rebecca Mckeever wrote:
> > > 
> > > > Replace ternary statement with an if statement followed by an assignment
> > > > to increase readability and make error handling more obvious.
> > > > Found with minmax coccinelle script.
> []
> > > > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> []
> > > > @@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
> > > >  		return 0;
> > > >  	}
> > > >  	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
> > > > -	erq->length = (len >= 0 ? len : 0);
> > > > +	if (len < 0)
> > > > +		len = 0;
> > > > +	erq->length = len;
> > > 
> > > Maybe you could use max here?
> > 
> > Initially Rebecca did use max() but I NAKed it.  It's really not less
> > readable.  Better to handle the error explicitly.  Keep the error path
> > indented two tabs.  Separate from the success path.
> 
> A comment would be useful as it's not obvious it's an 'error' path.
> One has to read all 3 get_key functions to determine that.
> 

I'm so confused.  Negative error codes are the common case in the
kernel.  We don't need to comment it.

Obviously in an ideal world the get_key() functions would return -EINVAL
instead of -1...

regards,
dan carpenter

Re: [PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Joe Perches]

On Fri, 2022-04-08 at 09:31 +0300, Dan Carpenter wrote:
> On Thu, Apr 07, 2022 at 11:14:51PM -0700, Joe Perches wrote:
> > On Fri, 2022-04-08 at 08:57 +0300, Dan Carpenter wrote:
> > > On Fri, Apr 08, 2022 at 06:15:14AM +0200, Julia Lawall wrote:
> > > > On Thu, 7 Apr 2022, Rebecca Mckeever wrote:
> > > > 
> > > > > Replace ternary statement with an if statement followed by an assignment
> > > > > to increase readability and make error handling more obvious.
> > > > > Found with minmax coccinelle script.
> > []
> > > > > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > []
> > > > > @@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
> > > > >  		return 0;
> > > > >  	}
> > > > >  	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
> > > > > -	erq->length = (len >= 0 ? len : 0);
> > > > > +	if (len < 0)
> > > > > +		len = 0;
> > > > > +	erq->length = len;
> > > > 
> > > > Maybe you could use max here?
> > > 
> > > Initially Rebecca did use max() but I NAKed it.  It's really not less
> > > readable.  Better to handle the error explicitly.  Keep the error path
> > > indented two tabs.  Separate from the success path.
> > 
> > A comment would be useful as it's not obvious it's an 'error' path.
> > One has to read all 3 get_key functions to determine that.
> > 
> 
> I'm so confused.  Negative error codes are the common case in the
> kernel.  We don't need to comment it.

If it was an error, it would handle it as an error not set
len to 0 and continue. That's why IMO a comment is useful.

Re: [PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Dan Carpenter]

On Fri, Apr 08, 2022 at 12:19:01AM -0700, Joe Perches wrote:
> On Fri, 2022-04-08 at 09:31 +0300, Dan Carpenter wrote:
> > On Thu, Apr 07, 2022 at 11:14:51PM -0700, Joe Perches wrote:
> > > On Fri, 2022-04-08 at 08:57 +0300, Dan Carpenter wrote:
> > > > On Fri, Apr 08, 2022 at 06:15:14AM +0200, Julia Lawall wrote:
> > > > > On Thu, 7 Apr 2022, Rebecca Mckeever wrote:
> > > > > 
> > > > > > Replace ternary statement with an if statement followed by an assignment
> > > > > > to increase readability and make error handling more obvious.
> > > > > > Found with minmax coccinelle script.
> > > []
> > > > > > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > > []
> > > > > > @@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
> > > > > >  		return 0;
> > > > > >  	}
> > > > > >  	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
> > > > > > -	erq->length = (len >= 0 ? len : 0);
> > > > > > +	if (len < 0)
> > > > > > +		len = 0;
> > > > > > +	erq->length = len;
> > > > > 
> > > > > Maybe you could use max here?
> > > > 
> > > > Initially Rebecca did use max() but I NAKed it.  It's really not less
> > > > readable.  Better to handle the error explicitly.  Keep the error path
> > > > indented two tabs.  Separate from the success path.
> > > 
> > > A comment would be useful as it's not obvious it's an 'error' path.
> > > One has to read all 3 get_key functions to determine that.
> > > 
> > 
> > I'm so confused.  Negative error codes are the common case in the
> > kernel.  We don't need to comment it.
> 
> If it was an error, it would handle it as an error not set
> len to 0 and continue. That's why IMO a comment is useful.

Yeah.  You're probably right.  My understanding is that a zero length
key is a special case where it uses the default key?  Which I guess is
all zeroes here.

	if (len < 0) {
		/* No key data.  Use the default key. */
		len = 0;
	}
But when I look at this some more then there are three ->get_key()
callers in this file and only this one checks for -1 returns.  For the
one caller that does this:

	ext->key_len = crypt->ops->get_key(ext->key, SCM_KEY_LEN, NULL, crypt->priv);

then a negative return would result in a buffer overflow.

So another option would be to just return 0 instead of -1 from the
get_key() functions.

File | Pointer | Function | Static
drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_tkip.c | (struct ieee80211_crypto_ops)->get_key | ieee80211_tkip_get_key | 1
drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_wep.c | (struct ieee80211_crypto_ops)->get_key | prism2_wep_get_key | 1
drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_ccmp.c | (struct ieee80211_crypto_ops)->get_key | ieee80211_ccmp_get_key | 1

Changing it to return zero would leave ieee80211_wx_get_encode() behavior
as-is.  It would fix a buffer overflow in ieee80211_wx_get_encode_ext().
It is a behavior change in ieee80211_wx_set_encode() and I think that's
a bug fix as well.

regards,
dan carpenter

Re: [PATCH v2 1/2] staging: rtl8192u: replace ternary statement with if and assignment

[Julia Lawall]

On Fri, 8 Apr 2022, Dan Carpenter wrote:

> On Fri, Apr 08, 2022 at 06:15:14AM +0200, Julia Lawall wrote:
> > On Thu, 7 Apr 2022, Rebecca Mckeever wrote:
> >
> > > Replace ternary statement with an if statement followed by an assignment
> > > to increase readability and make error handling more obvious.
> > > Found with minmax coccinelle script.
> > >
> > > Signed-off-by: Rebecca Mckeever <remckee0@gmail.com>
> > > ---
> > >  drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > > index 78cc8f357bbc..9885917b9199 100644
> > > --- a/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > > +++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c
> > > @@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
> > >  		return 0;
> > >  	}
> > >  	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
> > > -	erq->length = (len >= 0 ? len : 0);
> > > +	if (len < 0)
> > > +		len = 0;
> > > +	erq->length = len;
> >
> > Maybe you could use max here?
>
> Initially Rebecca did use max() but I NAKed it.  It's really not less
> readable.  Better to handle the error explicitly.  Keep the error path
> indented two tabs.  Separate from the success path.

OK.  I have a hard time seeing that as an error path, though, with no
return or goto.  I guess it's error and recover.  OK either way.

julia

[PATCH v2 2/2] staging: rtl8192u: use min_t/max_t macros instead of if else

[Rebecca Mckeever]

Replace if else statement with min_t or max_t macros to increase
readability and conform to Linux kernel coding style. The _t versions
of the macros must be used to avoid applying typeof to the bit fields
pPeerHTCap->MaxRxAMPDUFactor, and pPeerHTCap->MPDUDensity.

Using u32 assures the reader that the value with not be truncated
without having to look up the types of the variables involved.
Found with minmax coccinelle script.

Signed-off-by: Rebecca Mckeever <remckee0@gmail.com>
---
 drivers/staging/rtl8192u/ieee80211/rtl819x_HTProc.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/rtl8192u/ieee80211/rtl819x_HTProc.c b/drivers/staging/rtl8192u/ieee80211/rtl819x_HTProc.c
index dba3f2db9f48..358c35d9589c 100644
--- a/drivers/staging/rtl8192u/ieee80211/rtl819x_HTProc.c
+++ b/drivers/staging/rtl8192u/ieee80211/rtl819x_HTProc.c
@@ -940,10 +940,8 @@ void HTOnAssocRsp(struct ieee80211_device *ieee)
 			else
 				pHTInfo->CurrentAMPDUFactor = HT_AGG_SIZE_64K;
 		} else {
-			if (pPeerHTCap->MaxRxAMPDUFactor < HT_AGG_SIZE_32K)
-				pHTInfo->CurrentAMPDUFactor = pPeerHTCap->MaxRxAMPDUFactor;
-			else
-				pHTInfo->CurrentAMPDUFactor = HT_AGG_SIZE_32K;
+			pHTInfo->CurrentAMPDUFactor = min_t(u32, pPeerHTCap->MaxRxAMPDUFactor,
+							    HT_AGG_SIZE_32K);
 		}
 	}
 
@@ -951,10 +949,9 @@ void HTOnAssocRsp(struct ieee80211_device *ieee)
 	 * <2> Set AMPDU Minimum MPDU Start Spacing
 	 * 802.11n 3.0 section 9.7d.3
 	 */
-	if (pHTInfo->MPDU_Density > pPeerHTCap->MPDUDensity)
-		pHTInfo->CurrentMPDUDensity = pHTInfo->MPDU_Density;
-	else
-		pHTInfo->CurrentMPDUDensity = pPeerHTCap->MPDUDensity;
+	pHTInfo->CurrentMPDUDensity = max_t(u32, pHTInfo->MPDU_Density,
+					    pPeerHTCap->MPDUDensity);
+
 	if (ieee->pairwise_key_type != KEY_TYPE_NA)
 		pHTInfo->CurrentMPDUDensity	= 7; // 8us
 	// Force TX AMSDU
-- 
2.32.0

Re: [PATCH v2 0/2] staging: rtl8192u: cleanup of ternary and if else statements

[Dan Carpenter]

On Thu, Apr 07, 2022 at 08:12:49PM -0500, Rebecca Mckeever wrote:
> These patches replace ternary and if else statements with
> more readable statements. Found with minmax coccinelle script.
> 
> ---
> v1 -> v2:
> * Patch 1: "staging: rtl8192u: replace ternary statement with if and
> * assignment"
>   * replaced max macro with an if statement followed by an assignment
> 
> * Patch 2: "staging: rtl8192u: use min_t/max_t macros instead of if
> * else"
>   * changed the type argument in min_t and max_t from u8 to u32
> ---

Looks great.  Thanks!

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>

regards,
dan carpenter