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

From: Doug Ledford
Date: Fri Nov 10 2017 - 13:00:30 EST


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

Attachment: signature.asc
Description: This is a digitally signed message part