netdev - [PATCH net-next 15/15] team: Remove use of list iterator variable for list_for_each_entry

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Date:   Thu,  7 Apr 2022 12:29:00 +0200
From:   Jakob Koschel <jakobkoschel@...il.com>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        Lars Povlsen <lars.povlsen@...rochip.com>,
        Steen Hegelund <Steen.Hegelund@...rochip.com>,
        UNGLinuxDriver@...rochip.com, Ariel Elior <aelior@...vell.com>,
        Manish Chopra <manishc@...vell.com>,
        Edward Cree <ecree.xilinx@...il.com>,
        Martin Habets <habetsm.xilinx@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Jiri Pirko <jiri@...nulli.us>,
        Casper Andersson <casper.casan@...il.com>,
        Bjarni Jonasson <bjarni.jonasson@...rochip.com>,
        Jakob Koschel <jakobkoschel@...il.com>,
        Colin Ian King <colin.king@...el.com>,
        Michael Walle <michael@...le.cc>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Arnd Bergmann <arnd@...db.de>,
        Eric Dumazet <edumazet@...gle.com>,
        Di Zhu <zhudi21@...wei.com>, Xu Wang <vulab@...as.ac.cn>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linuxppc-dev@...ts.ozlabs.org, Mike Rapoport <rppt@...nel.org>,
        "Brian Johannesmeyer" <bjohannesmeyer@...il.com>,
        Cristiano Giuffrida <c.giuffrida@...nl>,
        "Bos, H.J." <h.j.bos@...nl>
Subject: [PATCH net-next 15/15] team: Remove use of list iterator variable for list_for_each_entry_from()

In preparation to limit the scope of the list iterator variable to the
list traversal loop, use a dedicated pointer to iterate through the
list [1].

Since that variable should not be used past the loop iteration, a
separate variable is used to 'remember the current location within the
loop'.
By avoiding the use of the iterator variable after the loop, we can lower
the scope of it to the list traversal macros in the future.

To either continue iterating from that position or skip the iteration
(if the previous iteration was complete) list_prepare_entry() is used.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Signed-off-by: Jakob Koschel <jakobkoschel@...il.com>
---
 drivers/net/team/team.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index b07dde6f0abf..688c4393f099 100644
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -2425,17 +2425,17 @@ static int team_nl_send_options_get(struct team *team, u32 portid, u32 seq,
 				    int flags, team_nl_send_func_t *send_func,
 				    struct list_head *sel_opt_inst_list)
 {
+	struct team_option_inst *opt_inst, *tmp = NULL;
 	struct nlattr *option_list;
 	struct nlmsghdr *nlh;
 	void *hdr;
-	struct team_option_inst *opt_inst;
 	int err;
 	struct sk_buff *skb = NULL;
 	bool incomplete;
 	int i;

-	opt_inst = list_first_entry(sel_opt_inst_list,
-				    struct team_option_inst, tmp_list);
+	tmp = list_first_entry(sel_opt_inst_list,
+			       struct team_option_inst, tmp_list);

 start_again:
 	err = __send_and_alloc_skb(&skb, team, portid, send_func);
@@ -2456,7 +2456,9 @@ static int team_nl_send_options_get(struct team *team, u32 portid, u32 seq,
 		goto nla_put_failure;

 	i = 0;
+	opt_inst = list_prepare_entry(tmp, sel_opt_inst_list, tmp_list);
 	incomplete = false;
+	tmp = NULL;
 	list_for_each_entry_from(opt_inst, sel_opt_inst_list, tmp_list) {
 		err = team_nl_fill_one_option_get(skb, team, opt_inst);
 		if (err) {
@@ -2464,6 +2466,7 @@ static int team_nl_send_options_get(struct team *team, u32 portid, u32 seq,
 				if (!i)
 					goto errout;
 				incomplete = true;
+				tmp = opt_inst;
 				break;
 			}
 			goto errout;
@@ -2707,14 +2710,14 @@ static int team_nl_send_port_list_get(struct team *team, u32 portid, u32 seq,
 	struct nlattr *port_list;
 	struct nlmsghdr *nlh;
 	void *hdr;
-	struct team_port *port;
+	struct team_port *port, *tmp = NULL;
 	int err;
 	struct sk_buff *skb = NULL;
 	bool incomplete;
 	int i;

-	port = list_first_entry_or_null(&team->port_list,
-					struct team_port, list);
+	tmp = list_first_entry_or_null(&team->port_list,
+				       struct team_port, list);

 start_again:
 	err = __send_and_alloc_skb(&skb, team, portid, send_func);
@@ -2744,7 +2747,9 @@ static int team_nl_send_port_list_get(struct team *team, u32 portid, u32 seq,
 		err = team_nl_fill_one_port_get(skb, one_port);
 		if (err)
 			goto errout;
-	} else if (port) {
+	} else {
+		port = list_prepare_entry(tmp, &team->port_list, list);
+		tmp = NULL;
 		list_for_each_entry_from(port, &team->port_list, list) {
 			err = team_nl_fill_one_port_get(skb, port);
 			if (err) {
@@ -2752,6 +2757,7 @@ static int team_nl_send_port_list_get(struct team *team, u32 portid, u32 seq,
 					if (!i)
 						goto errout;
 					incomplete = true;
+					tmp = port;
 					break;
 				}
 				goto errout;
--
2.25.1