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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-439b02ce685sm17224815e9.2.2025.02.21.05.17.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Feb 2025 05:17:53 -0800 (PST) Date: Fri, 21 Feb 2025 13:17:50 +0000 From: David Laight To: Uday Shankar Cc: Breno Leitao , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Srinivas Kandagatla , =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Simon Horman , Andrew Morton , Johannes Berg , Jonathan Corbet , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, linux-doc@vger.kernel.org, Michal Swiatkowski Subject: Re: [PATCH net-next v5 1/2] net, treewide: define and use MAC_ADDR_STR_LEN Message-ID: <20250221131750.0630c720@pumpkin> In-Reply-To: <20250220-netconsole-v5-1-4aeafa71debf@purestorage.com> References: <20250220-netconsole-v5-0-4aeafa71debf@purestorage.com> <20250220-netconsole-v5-1-4aeafa71debf@purestorage.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 20 Feb 2025 18:29:20 -0700 Uday Shankar wrote: > There are a few places in the tree which compute the length of the > string representation of a MAC address as 3 * ETH_ALEN - 1. Define a > constant for this and use it where relevant. No functionality changes > are expected. The fact that you have to keep adding 1 or 2 is a good indication that it really isn't a good idea. David > > Signed-off-by: Uday Shankar > Reviewed-by: Michal Swiatkowski > Acked-by: Johannes Berg > --- > drivers/net/netconsole.c | 2 +- > drivers/nvmem/brcm_nvram.c | 2 +- > drivers/nvmem/layouts/u-boot-env.c | 2 +- > include/linux/if_ether.h | 3 +++ > lib/net_utils.c | 4 +--- > net/mac80211/debugfs_sta.c | 7 ++++--- > 6 files changed, 11 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c > index f77eddf221850fe2778cd479e49c91ad695aba3c..12699831e3c9fdbafd4862a339aea4ef04cf522b 100644 > --- a/drivers/net/netconsole.c > +++ b/drivers/net/netconsole.c > @@ -721,7 +721,7 @@ static ssize_t remote_mac_store(struct config_item *item, const char *buf, > > if (!mac_pton(buf, remote_mac)) > goto out_unlock; > - if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n') > + if (buf[MAC_ADDR_STR_LEN] && buf[MAC_ADDR_STR_LEN] != '\n') > goto out_unlock; > memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN); > > diff --git a/drivers/nvmem/brcm_nvram.c b/drivers/nvmem/brcm_nvram.c > index b810df727b446b1762a1851750f743e0de6e8788..b4cf245fb2467d281111001bb7ed8db5993a09b2 100644 > --- a/drivers/nvmem/brcm_nvram.c > +++ b/drivers/nvmem/brcm_nvram.c > @@ -100,7 +100,7 @@ static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, i > { > u8 mac[ETH_ALEN]; > > - if (bytes != 3 * ETH_ALEN - 1) > + if (bytes != MAC_ADDR_STR_LEN) > return -EINVAL; > > if (!mac_pton(buf, mac)) > diff --git a/drivers/nvmem/layouts/u-boot-env.c b/drivers/nvmem/layouts/u-boot-env.c > index 731e6f4f12b2bf28e4547d128954a095545ad461..436426d4e8f910b51b92f88acddfbb40d374587a 100644 > --- a/drivers/nvmem/layouts/u-boot-env.c > +++ b/drivers/nvmem/layouts/u-boot-env.c > @@ -37,7 +37,7 @@ static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, i > { > u8 mac[ETH_ALEN]; > > - if (bytes != 3 * ETH_ALEN - 1) > + if (bytes != MAC_ADDR_STR_LEN) > return -EINVAL; > > if (!mac_pton(buf, mac)) > diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h > index 8a9792a6427ad9cf58b50c79cbfe185615800dcb..61b7335aa037c7232a0caa45572043057c02dde3 100644 > --- a/include/linux/if_ether.h > +++ b/include/linux/if_ether.h > @@ -19,6 +19,9 @@ > #include > #include > > +/* XX:XX:XX:XX:XX:XX */ > +#define MAC_ADDR_STR_LEN (3 * ETH_ALEN - 1) > + > static inline struct ethhdr *eth_hdr(const struct sk_buff *skb) > { > return (struct ethhdr *)skb_mac_header(skb); > diff --git a/lib/net_utils.c b/lib/net_utils.c > index 42bb0473fb22f977409f7a6792bb1340f4e911c3..215cda672fee1b5a029c2b61529c6813c0edab11 100644 > --- a/lib/net_utils.c > +++ b/lib/net_utils.c > @@ -7,11 +7,9 @@ > > bool mac_pton(const char *s, u8 *mac) > { > - size_t maxlen = 3 * ETH_ALEN - 1; > int i; > > - /* XX:XX:XX:XX:XX:XX */ > - if (strnlen(s, maxlen) < maxlen) > + if (strnlen(s, MAC_ADDR_STR_LEN) < MAC_ADDR_STR_LEN) > return false; > > /* Don't dirty result unless string is valid MAC. */ > diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c > index a67a9d3160086ac492d77092a0c8a74d2384b28c..a8948f4d983e5edee45d90ad267582657ed38e38 100644 > --- a/net/mac80211/debugfs_sta.c > +++ b/net/mac80211/debugfs_sta.c > @@ -457,11 +457,12 @@ static ssize_t link_sta_addr_read(struct file *file, char __user *userbuf, > size_t count, loff_t *ppos) > { > struct link_sta_info *link_sta = file->private_data; > - u8 mac[3 * ETH_ALEN + 1]; > + u8 mac[MAC_ADDR_STR_LEN + 2]; > > snprintf(mac, sizeof(mac), "%pM\n", link_sta->pub->addr); > > - return simple_read_from_buffer(userbuf, count, ppos, mac, 3 * ETH_ALEN); > + return simple_read_from_buffer(userbuf, count, ppos, mac, > + MAC_ADDR_STR_LEN + 1); > } > > LINK_STA_OPS(addr); > @@ -1240,7 +1241,7 @@ void ieee80211_sta_debugfs_add(struct sta_info *sta) > struct ieee80211_local *local = sta->local; > struct ieee80211_sub_if_data *sdata = sta->sdata; > struct dentry *stations_dir = sta->sdata->debugfs.subdir_stations; > - u8 mac[3*ETH_ALEN]; > + u8 mac[MAC_ADDR_STR_LEN + 1]; > > if (!stations_dir) > return; >