[PATCH v3 1/2] net, treewide: define and use MAC_ADDR_STR_LEN

[Uday Shankar <ushankar@purestorage.com>]

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.

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
---
 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         | 5 +++--
 6 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 86ab4a42769a49eebe5dd6f01dafafc6c86ec54f..6db5af2d8d059fa5c072194545d4408eec19b4a9 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -675,7 +675,7 @@ 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 <linux/skbuff.h>
 #include <uapi/linux/if_ether.h>
 
+/* 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..11d51e348339f1eec1a7d3fd04b1439aaed64593 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);

-- 
2.34.1