linux-kernel - [PATCH] net: sched: One function call less in em_meta

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Message-ID: <54CD042E.6030606@users.sourceforge.net>
Date:	Sat, 31 Jan 2015 17:34:54 +0100
From:	SF Markus Elfring <elfring@...rs.sourceforge.net>
To:	"David S. Miller" <davem@...emloft.net>,
	Jamal Hadi Salim <jhs@...atatu.com>, netdev@...r.kernel.org
CC:	LKML <linux-kernel@...r.kernel.org>,
	kernel-janitors@...r.kernel.org,
	Julia Lawall <julia.lawall@...6.fr>
Subject: [PATCH] net: sched: One function call less in em_meta_change() after
 error detection

From: Markus Elfring <elfring@...rs.sourceforge.net>
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 <elfring@...rs.sourceforge.net>
---
 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;
 }
 
-- 
2.2.2

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