Re: [PATCH] IB/qib: remove redundant setting of any in for-loop

[Doug Ledford]

On Fri, 2017-10-20 at 00:35 -0700, Joe Perches wrote:
> On Fri, 2017-10-20 at 09:21 +0200, Colin King wrote:
> > From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > 
> > The variable all is being set but is never read after this
> > hence it can be removed from the for loop initialization.
> > Cleans up clang warning:
> 
> any is really used as bool and is initialized at function
> entry.  The earlier loop also reinitializes any unnecessarily.

Denny, can you weigh in on what you want in this thread?  Thanks.

> > drivers/infiniband/hw/qib/qib_file_ops.c:640:7: warning: Value
> > stored to 'any' is never read
> > 
> > Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > ---
> >  drivers/infiniband/hw/qib/qib_file_ops.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
> > index 2d6a191afec0..b5c2e4223ee7 100644
> > --- a/drivers/infiniband/hw/qib/qib_file_ops.c
> > +++ b/drivers/infiniband/hw/qib/qib_file_ops.c
> > @@ -637,7 +637,7 @@ static int qib_set_part_key(struct qib_ctxtdata *rcd, u16 key)
> >  		ret = -EBUSY;
> >  		goto bail;
> >  	}
> > -	for (any = i = 0; i < ARRAY_SIZE(ppd->pkeys); i++) {
> > +	for (i = 0; i < ARRAY_SIZE(ppd->pkeys); i++) {
> >  		if (!ppd->pkeys[i] &&
> >  		    atomic_inc_return(&ppd->pkeyrefs[i]) == 1) {
> >  			rcd->pkeys[pidx] = key;
> 
> Perhaps the function is better written without
> the empty bail: label and without setting ret
> and just using return.
> 
> Combining the int/bool conversion of any and the
> direct returns seems clearer to me.
> 
> Something like:
> ---
>  drivers/infiniband/hw/qib/qib_file_ops.c | 70 ++++++++++++--------------------
>  1 file changed, 27 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
> index 2d6a191afec0..8078854e1cd6 100644
> --- a/drivers/infiniband/hw/qib/qib_file_ops.c
> +++ b/drivers/infiniband/hw/qib/qib_file_ops.c
> @@ -568,20 +568,17 @@ static int qib_tid_free(struct qib_ctxtdata *rcd, unsigned subctxt,
>  static int qib_set_part_key(struct qib_ctxtdata *rcd, u16 key)
>  {
>  	struct qib_pportdata *ppd = rcd->ppd;
> -	int i, any = 0, pidx = -1;
> +	int i;
> +	bool any = false;
> +	int pidx = -1;
>  	u16 lkey = key & 0x7FFF;
> -	int ret;
>  
> -	if (lkey == (QIB_DEFAULT_P_KEY & 0x7FFF)) {
> -		/* nothing to do; this key always valid */
> -		ret = 0;
> -		goto bail;
> -	}
> +	/* nothing to do; this key always valid */
> +	if (lkey == (QIB_DEFAULT_P_KEY & 0x7FFF))
> +		return 0;
>  
> -	if (!lkey) {
> -		ret = -EINVAL;
> -		goto bail;
> -	}
> +	if (!lkey)
> +		return -EINVAL;
>  
>  	/*
>  	 * Set the full membership bit, because it has to be
> @@ -594,18 +591,15 @@ static int qib_set_part_key(struct qib_ctxtdata *rcd, u16 key)
>  	for (i = 0; i < ARRAY_SIZE(rcd->pkeys); i++) {
>  		if (!rcd->pkeys[i] && pidx == -1)
>  			pidx = i;
> -		if (rcd->pkeys[i] == key) {
> -			ret = -EEXIST;
> -			goto bail;
> -		}
> -	}
> -	if (pidx == -1) {
> -		ret = -EBUSY;
> -		goto bail;
> +		if (rcd->pkeys[i] == key)
> +			return -EEXIST;
>  	}
> -	for (any = i = 0; i < ARRAY_SIZE(ppd->pkeys); i++) {
> +	if (pidx == -1)
> +		return -EBUSY;
> +
> +	for (i = 0; i < ARRAY_SIZE(ppd->pkeys); i++) {
>  		if (!ppd->pkeys[i]) {
> -			any++;
> +			any = true;
>  			continue;
>  		}
>  		if (ppd->pkeys[i] == key) {
> @@ -613,44 +607,34 @@ static int qib_set_part_key(struct qib_ctxtdata *rcd, u16 key)
>  
>  			if (atomic_inc_return(pkrefs) > 1) {
>  				rcd->pkeys[pidx] = key;
> -				ret = 0;
> -				goto bail;
> -			} else {
> -				/*
> -				 * lost race, decrement count, catch below
> -				 */
> -				atomic_dec(pkrefs);
> -				any++;
> +				return 0;
>  			}
> +			/* lost race, decrement count, catch below */
> +			atomic_dec(pkrefs);
> +			any = true;
>  		}
> -		if ((ppd->pkeys[i] & 0x7FFF) == lkey) {
> +		if ((ppd->pkeys[i] & 0x7FFF) == lkey)
>  			/*
>  			 * It makes no sense to have both the limited and
>  			 * full membership PKEY set at the same time since
>  			 * the unlimited one will disable the limited one.
>  			 */
> -			ret = -EEXIST;
> -			goto bail;
> -		}
> -	}
> -	if (!any) {
> -		ret = -EBUSY;
> -		goto bail;
> +			return -EEXIST;
>  	}
> -	for (any = i = 0; i < ARRAY_SIZE(ppd->pkeys); i++) {
> +	if (!any)
> +		return -EBUSY;
> +
> +	for (i = 0; i < ARRAY_SIZE(ppd->pkeys); i++) {
>  		if (!ppd->pkeys[i] &&
>  		    atomic_inc_return(&ppd->pkeyrefs[i]) == 1) {
>  			rcd->pkeys[pidx] = key;
>  			ppd->pkeys[i] = key;
>  			(void) ppd->dd->f_set_ib_cfg(ppd, QIB_IB_CFG_PKEYS, 0);
> -			ret = 0;
> -			goto bail;
> +			return 0;
>  		}
>  	}
> -	ret = -EBUSY;
>  
> -bail:
> -	return ret;
> +	return -EBUSY;
>  }
>  
>  /**

-- 
Doug Ledford <dledford@xxxxxxxxxx>
    GPG KeyID: B826A3330E572FDD
    Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD

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