From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lino Sanfilippo Date: Sat, 31 Jan 2015 17:31:08 +0000 Subject: Re: [PATCH] net: sched: One function call less in em_meta_change() after error detection Message-Id: <54CD115C.8070801@gmx.de> List-Id: References: <5307CAA2.8060406@users.sourceforge.net> <530A086E.8010901@users.sourceforge.net> <530A72AA.3000601@users.sourceforge.net> <530B5FB6.6010207@users.sourceforge.net> <530C5E18.1020800@users.sourceforge.net> <530CD2C4.4050903@users.sourceforge.net> <530CF8FF.8080600@users.sourceforge.net> <530DD06F.4090703@users.sourceforge.net> <5317A59D.4@users.sourceforge.net> <54CD042E.6030606@users.sourceforge.net> In-Reply-To: <54CD042E.6030606@users.sourceforge.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: SF Markus Elfring , "David S. Miller" , Jamal Hadi Salim , netdev@vger.kernel.org Cc: LKML , kernel-janitors@vger.kernel.org, Julia Lawall Hi, On 31.01.2015 17:34, SF Markus Elfring wrote: > From: Markus Elfring > Date: Sat, 31 Jan 2015 17:18:48 +0100 > > The meta_delete() function could be called in four cases by the > em_meta_change() function during error handling even if the passed > variable "meta" contained still a null pointer. > > * This implementation detail could be improved by adjustments for jump labels. > > * Let us return immediately after the first failed function call according to > the current Linux coding style convention. > > * Let us delete also unnecessary checks for the variables "err" and > "meta" there. > > Signed-off-by: Markus Elfring > --- > net/sched/em_meta.c | 20 ++++++++++---------- > 1 file changed, 10 insertions(+), 10 deletions(-) > > diff --git a/net/sched/em_meta.c b/net/sched/em_meta.c > index b5294ce..2aa67b1 100644 > --- a/net/sched/em_meta.c > +++ b/net/sched/em_meta.c > @@ -866,23 +866,23 @@ static int em_meta_change(struct net *net, void *data, int len, > > err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy); > if (err < 0) > - goto errout; > + return err; > > err = -EINVAL; > if (tb[TCA_EM_META_HDR] = NULL) > - goto errout; > + goto exit; > hdr = nla_data(tb[TCA_EM_META_HDR]); > > if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) || > TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX || > TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX || > TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX) > - goto errout; > + goto exit; > > meta = kzalloc(sizeof(*meta), GFP_KERNEL); > if (meta = NULL) { > err = -ENOMEM; > - goto errout; > + goto exit; > } > > memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left)); > @@ -891,20 +891,20 @@ static int em_meta_change(struct net *net, void *data, int len, > if (!meta_is_supported(&meta->lvalue) || > !meta_is_supported(&meta->rvalue)) { > err = -EOPNOTSUPP; > - goto errout; > + goto delete_meta; > } > > if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 || > meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0) > - goto errout; > + goto delete_meta; > > m->datalen = sizeof(*meta); > m->data = (unsigned long) meta; > > - err = 0; > -errout: > - if (err && meta) > - meta_delete(meta); > + return 0; > +delete_meta: > + meta_delete(meta); > +exit: > return err; > } Why do you use that exit label if it does nothing more than returning the error value? Also if nla_parse fails you dont use it but return the error directly. While using a label which is used only to return an error may be a matter of taste, its at least inconsistent to do both in a function, use such a label in one case and return immediately in another, isnt it? Regards, Lino