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[62.195.130.160]) by smtp.googlemail.com with ESMTPSA id b5-20020a17090630c500b006e8044fa76bsm8827900ejb.143.2022.04.12.05.16.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Apr 2022 05:16:23 -0700 (PDT) From: Jakob Koschel To: "David S. Miller" Subject: [PATCH net-next v3 02/18] net: dsa: sja1105: remove use of iterator after list_for_each_entry() loop Date: Tue, 12 Apr 2022 14:15:41 +0200 Message-Id: <20220412121557.3553555-3-jakobkoschel@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220412121557.3553555-1-jakobkoschel@gmail.com> References: <20220412121557.3553555-1-jakobkoschel@gmail.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Lunn , Song Liu , Alexei Starovoitov , Eric Dumazet , Paul Mackerras , Ariel Elior , Florian Fainelli , Daniel Borkmann , Steen Hegelund , John Fastabend , Andrii Nakryiko , "Bos, H.J." , Jason Gunthorpe , linux-arm-kernel@lists.infradead.org, Vladimir Oltean , Martin Habets , Paolo Abeni , Vivien Didelot , Bjarni Jonasson , Jiri Pirko , Arnd Bergmann , Brian Johannesmeyer , KP Singh , Christophe JAILLET , Jakob Koschel , Jakub Kicinski , Di Zhu , Lars Povlsen , Colin Ian King , Manish Chopra , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, UNGLinuxDriver@microchip.com, Yonghong Song , Edward Cree , Michael Walle , Casper Andersson , Xu Wang , Cristiano Giuffrida , bpf@vger.kernel.org, Vladimir Oltean , linuxppc-dev@lists.ozlabs.org, Martin KaFai Lau , Mike Rapoport Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Vladimir Oltean The link below explains that there is a desire to syntactically change list_for_each_entry() and list_for_each() such that it becomes impossible to use the iterator variable outside the scope of the loop. Although sja1105_insert_gate_entry() makes legitimate use of the iterator pointer when it breaks out, the pattern it uses may become illegal, so it needs to change. It is deemed acceptable to use a copy of the loop iterator, and sja1105_insert_gate_entry() only needs to know the list_head element before which the list insertion should be made. So let's profit from the occasion and refactor the list iteration to a dedicated function. An additional benefit is given by the fact that with the helper function in place, we no longer need to special-case the empty list, since it is equivalent to not having found any gating entry larger than the specified interval in the list. We just need to insert at the tail of that list (list_add vs list_add_tail on an empty list does the same thing). Link: https://patchwork.kernel.org/project/netdevbpf/patch/20220407102900.3086255-3-jakobkoschel@gmail.com/#24810127 Signed-off-by: Vladimir Oltean Signed-off-by: Jakob Koschel --- drivers/net/dsa/sja1105/sja1105_vl.c | 46 ++++++++++++++++++---------- 1 file changed, 29 insertions(+), 17 deletions(-) diff --git a/drivers/net/dsa/sja1105/sja1105_vl.c b/drivers/net/dsa/sja1105/sja1105_vl.c index b7e95d60a6e4..369be2ac3587 100644 --- a/drivers/net/dsa/sja1105/sja1105_vl.c +++ b/drivers/net/dsa/sja1105/sja1105_vl.c @@ -7,6 +7,27 @@ #define SJA1105_SIZE_VL_STATUS 8 +static struct list_head * +sja1105_first_entry_longer_than(struct list_head *entries, + s64 interval, + struct netlink_ext_ack *extack) +{ + struct sja1105_gate_entry *p; + + list_for_each_entry(p, entries, list) { + if (p->interval == interval) { + NL_SET_ERR_MSG_MOD(extack, "Gate conflict"); + return ERR_PTR(-EBUSY); + } + + if (interval < p->interval) + return &p->list; + } + + /* Empty list, or specified interval is largest within the list */ + return entries; +} + /* Insert into the global gate list, sorted by gate action time. */ static int sja1105_insert_gate_entry(struct sja1105_gating_config *gating_cfg, struct sja1105_rule *rule, @@ -14,6 +35,7 @@ static int sja1105_insert_gate_entry(struct sja1105_gating_config *gating_cfg, struct netlink_ext_ack *extack) { struct sja1105_gate_entry *e; + struct list_head *pos; int rc; e = kzalloc(sizeof(*e), GFP_KERNEL); @@ -24,25 +46,15 @@ static int sja1105_insert_gate_entry(struct sja1105_gating_config *gating_cfg, e->gate_state = gate_state; e->interval = entry_time; - if (list_empty(&gating_cfg->entries)) { - list_add(&e->list, &gating_cfg->entries); - } else { - struct sja1105_gate_entry *p; - - list_for_each_entry(p, &gating_cfg->entries, list) { - if (p->interval == e->interval) { - NL_SET_ERR_MSG_MOD(extack, - "Gate conflict"); - rc = -EBUSY; - goto err; - } - - if (e->interval < p->interval) - break; - } - list_add(&e->list, p->list.prev); + pos = sja1105_first_entry_longer_than(&gating_cfg->entries, + e->interval, extack); + if (IS_ERR(pos)) { + rc = PTR_ERR(pos); + goto err; } + list_add(&e->list, pos->prev); + gating_cfg->num_entries++; return 0;