diff mbox series

staging: rtl8192e: Use min_t/max_t macros for variable comparison

Message ID Y2LxC2kziM1TznhO@qemulion
State New
Headers
Series staging: rtl8192e: Use min_t/max_t macros for variable comparison |

Commit Message

Deepak R Varma Nov. 2, 2022, 10:36 p.m. UTC 
  Simplify code by using min_t and max_t helper macros in place of lengthy
if/else block oriented logical evaluation and value assignment. This
issue is identified by coccicheck using the minmax.cocci file.

Use the *_t variants of min/max macros to avoid compiler warnings about
data typecast.
Also, use u32 as type for min_t macro to avoid any truncation of data
associated with enum constant HT_AGG_SIZE_32K.

Signed-off-by: Deepak R Varma <drv@mailo.com>
---
 drivers/staging/rtl8192e/rtl819x_HTProc.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

--
2.34.1

Comments

Philipp Hortmann Nov. 2, 2022, 10:56 p.m. UTC | #1 
On 11/2/22 23:36, Deepak R Varma wrote:
> Simplify code by using min_t and max_t helper macros in place of lengthy
> if/else block oriented logical evaluation and value assignment. This
> issue is identified by coccicheck using the minmax.cocci file.
> 
> Use the *_t variants of min/max macros to avoid compiler warnings about
> data typecast.
> Also, use u32 as type for min_t macro to avoid any truncation of data
> associated with enum constant HT_AGG_SIZE_32K.
> 
> Signed-off-by: Deepak R Varma <drv@mailo.com>
> ---
>   drivers/staging/rtl8192e/rtl819x_HTProc.c | 13 ++++---------
>   1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/staging/rtl8192e/rtl819x_HTProc.c b/drivers/staging/rtl8192e/rtl819x_HTProc.c
> index 62aa8e893c34..ccb86660ab48 100644
> --- a/drivers/staging/rtl8192e/rtl819x_HTProc.c
> +++ b/drivers/staging/rtl8192e/rtl819x_HTProc.c
> @@ -587,17 +587,12 @@ void HTOnAssocRsp(struct rtllib_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);
>   		}
>   	}
> -	if (pHTInfo->MPDU_Density > pPeerHTCap->MPDUDensity)
> -		pHTInfo->current_mpdu_density = pHTInfo->MPDU_Density;
> -	else
> -		pHTInfo->current_mpdu_density = pPeerHTCap->MPDUDensity;
> +	pHTInfo->current_mpdu_density = max_t(u8, pHTInfo->MPDU_Density,
> +					      pPeerHTCap->MPDUDensity);
>   	if (pHTInfo->iot_action & HT_IOT_ACT_TX_USE_AMSDU_8K) {
>   		pHTInfo->bCurrentAMPDUEnable = false;
>   		pHTInfo->ForcedAMSDUMode = HT_AGG_FORCE_ENABLE;
> --
> 2.34.1
> 
> 
> 
> 

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
David Laight Nov. 3, 2022, 8:24 a.m. UTC | #2 
From: Deepak R Varma
> Sent: 02 November 2022 22:37
> 
> Simplify code by using min_t and max_t helper macros in place of lengthy
> if/else block oriented logical evaluation and value assignment. This
> issue is identified by coccicheck using the minmax.cocci file.
> 
> Use the *_t variants of min/max macros to avoid compiler warnings about
> data typecast.
> Also, use u32 as type for min_t macro to avoid any truncation of data
> associated with enum constant HT_AGG_SIZE_32K.
> 
> Signed-off-by: Deepak R Varma <drv@mailo.com>
> ---
>  drivers/staging/rtl8192e/rtl819x_HTProc.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/staging/rtl8192e/rtl819x_HTProc.c b/drivers/staging/rtl8192e/rtl819x_HTProc.c
> index 62aa8e893c34..ccb86660ab48 100644
> --- a/drivers/staging/rtl8192e/rtl819x_HTProc.c
> +++ b/drivers/staging/rtl8192e/rtl819x_HTProc.c
> @@ -587,17 +587,12 @@ void HTOnAssocRsp(struct rtllib_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);

For min() to fail there must be a signed v unsigned mismatch.
Maybe that ought to be fixed.

>  		}
>  	}
> -	if (pHTInfo->MPDU_Density > pPeerHTCap->MPDUDensity)
> -		pHTInfo->current_mpdu_density = pHTInfo->MPDU_Density;
> -	else
> -		pHTInfo->current_mpdu_density = pPeerHTCap->MPDUDensity;
> +	pHTInfo->current_mpdu_density = max_t(u8, pHTInfo->MPDU_Density,
> +					      pPeerHTCap->MPDUDensity);

Using u8 with max_t() really doesn't make any sense.
The value will get promoted to signed int prior to the comparison.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
Dan Carpenter Nov. 3, 2022, 8:53 a.m. UTC | #3 
On Thu, Nov 03, 2022 at 08:24:15AM +0000, David Laight wrote:
> > --- a/drivers/staging/rtl8192e/rtl819x_HTProc.c
> > +++ b/drivers/staging/rtl8192e/rtl819x_HTProc.c
> > @@ -587,17 +587,12 @@ void HTOnAssocRsp(struct rtllib_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);
> 
> For min() to fail there must be a signed v unsigned mismatch.
> Maybe that ought to be fixed.
> 

u32 is the right choice here.

I'm having a hard time understanding your email.  You might be saying
we could declare HT_AGG_SIZE_32K as a u32 so then we could use min()
instead of min_t()?  HT_AGG_SIZE_32K is an enum.

pPeerHTCap->MaxRxAMPDUFactor is a bitfield.

	u8 MaxRxAMPDUFactor:2;

We will never be able to use min().

> >  		}
> >  	}
> > -	if (pHTInfo->MPDU_Density > pPeerHTCap->MPDUDensity)
> > -		pHTInfo->current_mpdu_density = pHTInfo->MPDU_Density;
> > -	else
> > -		pHTInfo->current_mpdu_density = pPeerHTCap->MPDUDensity;
> > +	pHTInfo->current_mpdu_density = max_t(u8, pHTInfo->MPDU_Density,
> > +					      pPeerHTCap->MPDUDensity);
> 
> Using u8 with max_t() really doesn't make any sense.

Using u8 looks wrong because you would worry that one of the types is
larger than U8_MAX.  But it's actually fine.  The types are u8 vs another
bitfield.  I would probably have gone with u32 here as well.

> The value will get promoted to signed int prior to the comparison.
> 

That's sort of true-ish but I don't understand what you are saying?
#confused

regards,
dan carpenter
Deepak R Varma Nov. 3, 2022, 9:18 a.m. UTC | #4 
On Thu, Nov 03, 2022 at 11:53:45AM +0300, Dan Carpenter wrote:
> On Thu, Nov 03, 2022 at 08:24:15AM +0000, David Laight wrote:
> > > --- a/drivers/staging/rtl8192e/rtl819x_HTProc.c
> > > +++ b/drivers/staging/rtl8192e/rtl819x_HTProc.c
> > > @@ -587,17 +587,12 @@ void HTOnAssocRsp(struct rtllib_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);
> >
> > For min() to fail there must be a signed v unsigned mismatch.
> > Maybe that ought to be fixed.
> >
>
> u32 is the right choice here.
>
> I'm having a hard time understanding your email.  You might be saying
> we could declare HT_AGG_SIZE_32K as a u32 so then we could use min()
> instead of min_t()?  HT_AGG_SIZE_32K is an enum.
>
> pPeerHTCap->MaxRxAMPDUFactor is a bitfield.
>
> 	u8 MaxRxAMPDUFactor:2;
>
> We will never be able to use min().

I think we could do min((u32)a, (u32)b), but it is just unwrapped min_t
if I understand David's comment.

>
> > >  		}
> > >  	}
> > > -	if (pHTInfo->MPDU_Density > pPeerHTCap->MPDUDensity)
> > > -		pHTInfo->current_mpdu_density = pHTInfo->MPDU_Density;
> > > -	else
> > > -		pHTInfo->current_mpdu_density = pPeerHTCap->MPDUDensity;
> > > +	pHTInfo->current_mpdu_density = max_t(u8, pHTInfo->MPDU_Density,
> > > +					      pPeerHTCap->MPDUDensity);
> >
> > Using u8 with max_t() really doesn't make any sense.
>
> Using u8 looks wrong because you would worry that one of the types is
> larger than U8_MAX.  But it's actually fine.  The types are u8 vs another
> bitfield.  I would probably have gone with u32 here as well.
I will take your advise and upgrade the type to u32 as a revision.
>
> > The value will get promoted to signed int prior to the comparison.
> >
>
> That's sort of true-ish but I don't understand what you are saying?
> #confused

Yes, I too did not understand David's comment. I tried to dig dipper into max_t but
it gets very complex. Can you please elaborate how you determined the promotion
to signed int?

>
> regards,
> dan carpenter
>
>
Dan Carpenter Nov. 3, 2022, 10:09 a.m. UTC | #5 
On Thu, Nov 03, 2022 at 02:48:35PM +0530, Deepak R Varma wrote:
> On Thu, Nov 03, 2022 at 11:53:45AM +0300, Dan Carpenter wrote:
> > On Thu, Nov 03, 2022 at 08:24:15AM +0000, David Laight wrote:
> > > > --- a/drivers/staging/rtl8192e/rtl819x_HTProc.c
> > > > +++ b/drivers/staging/rtl8192e/rtl819x_HTProc.c
> > > > @@ -587,17 +587,12 @@ void HTOnAssocRsp(struct rtllib_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);
> > >
> > > For min() to fail there must be a signed v unsigned mismatch.
> > > Maybe that ought to be fixed.
> > >
> >
> > u32 is the right choice here.
> >
> > I'm having a hard time understanding your email.  You might be saying
> > we could declare HT_AGG_SIZE_32K as a u32 so then we could use min()
> > instead of min_t()?  HT_AGG_SIZE_32K is an enum.
> >
> > pPeerHTCap->MaxRxAMPDUFactor is a bitfield.
> >
> > 	u8 MaxRxAMPDUFactor:2;
> >
> > We will never be able to use min().
> 
> I think we could do min((u32)a, (u32)b), but it is just unwrapped min_t
> if I understand David's comment.
> 

No.  Do not do that.  I think it's a checkpatch warning.  What you have
is fine.

> >
> > > >  		}
> > > >  	}
> > > > -	if (pHTInfo->MPDU_Density > pPeerHTCap->MPDUDensity)
> > > > -		pHTInfo->current_mpdu_density = pHTInfo->MPDU_Density;
> > > > -	else
> > > > -		pHTInfo->current_mpdu_density = pPeerHTCap->MPDUDensity;
> > > > +	pHTInfo->current_mpdu_density = max_t(u8, pHTInfo->MPDU_Density,
> > > > +					      pPeerHTCap->MPDUDensity);
> > >
> > > Using u8 with max_t() really doesn't make any sense.
> >
> > Using u8 looks wrong because you would worry that one of the types is
> > larger than U8_MAX.  But it's actually fine.  The types are u8 vs another
> > bitfield.  I would probably have gone with u32 here as well.
> I will take your advise and upgrade the type to u32 as a revision.

Sounds good.  It's not something I would have asked you to redo the
patch over, but it would have been my personal preference.

regards,
dan carpenter
Deepak R Varma Nov. 4, 2022, 8:01 a.m. UTC | #6 
On Thu, Nov 03, 2022 at 01:09:20PM +0300, Dan Carpenter wrote:
> On Thu, Nov 03, 2022 at 02:48:35PM +0530, Deepak R Varma wrote:
> > On Thu, Nov 03, 2022 at 11:53:45AM +0300, Dan Carpenter wrote:
> > > On Thu, Nov 03, 2022 at 08:24:15AM +0000, David Laight wrote:
> > > > > --- a/drivers/staging/rtl8192e/rtl819x_HTProc.c
> > > > > +++ b/drivers/staging/rtl8192e/rtl819x_HTProc.c
> > > > > @@ -587,17 +587,12 @@ void HTOnAssocRsp(struct rtllib_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);
> > > >
> > > > For min() to fail there must be a signed v unsigned mismatch.
> > > > Maybe that ought to be fixed.
> > > >
> > >
> > > u32 is the right choice here.
> > >
> > > I'm having a hard time understanding your email.  You might be saying
> > > we could declare HT_AGG_SIZE_32K as a u32 so then we could use min()
> > > instead of min_t()?  HT_AGG_SIZE_32K is an enum.
> > >
> > > pPeerHTCap->MaxRxAMPDUFactor is a bitfield.
> > >
> > > 	u8 MaxRxAMPDUFactor:2;
> > >
> > > We will never be able to use min().
> >
> > I think we could do min((u32)a, (u32)b), but it is just unwrapped min_t
> > if I understand David's comment.
> >
>
> No.  Do not do that.  I think it's a checkpatch warning.  What you have
> is fine.
>
> > >
> > > > >  		}
> > > > >  	}
> > > > > -	if (pHTInfo->MPDU_Density > pPeerHTCap->MPDUDensity)
> > > > > -		pHTInfo->current_mpdu_density = pHTInfo->MPDU_Density;
> > > > > -	else
> > > > > -		pHTInfo->current_mpdu_density = pPeerHTCap->MPDUDensity;
> > > > > +	pHTInfo->current_mpdu_density = max_t(u8, pHTInfo->MPDU_Density,
> > > > > +					      pPeerHTCap->MPDUDensity);
> > > >
> > > > Using u8 with max_t() really doesn't make any sense.
> > >
> > > Using u8 looks wrong because you would worry that one of the types is
> > > larger than U8_MAX.  But it's actually fine.  The types are u8 vs another
> > > bitfield.  I would probably have gone with u32 here as well.
> > I will take your advise and upgrade the type to u32 as a revision.
>
> Sounds good.  It's not something I would have asked you to redo the
> patch over, but it would have been my personal preference.

That is no problem. I am waiting on David to elaborate on his feedback and
accordingly plan a consolidated revision.

>
> regards,
> dan carpenter
>
>
diff mbox series

Patch

diff --git a/drivers/staging/rtl8192e/rtl819x_HTProc.c b/drivers/staging/rtl8192e/rtl819x_HTProc.c
index 62aa8e893c34..ccb86660ab48 100644
--- a/drivers/staging/rtl8192e/rtl819x_HTProc.c
+++ b/drivers/staging/rtl8192e/rtl819x_HTProc.c
@@ -587,17 +587,12 @@  void HTOnAssocRsp(struct rtllib_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);
 		}
 	}
-	if (pHTInfo->MPDU_Density > pPeerHTCap->MPDUDensity)
-		pHTInfo->current_mpdu_density = pHTInfo->MPDU_Density;
-	else
-		pHTInfo->current_mpdu_density = pPeerHTCap->MPDUDensity;
+	pHTInfo->current_mpdu_density = max_t(u8, pHTInfo->MPDU_Density,
+					      pPeerHTCap->MPDUDensity);
 	if (pHTInfo->iot_action & HT_IOT_ACT_TX_USE_AMSDU_8K) {
 		pHTInfo->bCurrentAMPDUEnable = false;
 		pHTInfo->ForcedAMSDUMode = HT_AGG_FORCE_ENABLE;