netdev - [PATCH net-next] net: minor __dev_alloc

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Date:   Wed,  2 Feb 2022 22:46:09 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     netdev <netdev@...r.kernel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH net-next] net: minor __dev_alloc_name() optimization

From: Eric Dumazet <edumazet@...gle.com>

__dev_alloc_name() allocates a private zeroed page,
then sets bits in it while iterating through net devices.

It can use __set_bit() to avoid unecessary locked operations.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/core/dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 1baab07820f65f9bcf88a6d73e2c9ff741d33c18..f79744d99413434ad28b26dee9aeeb2893a0e3ae 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1037,7 +1037,7 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf)
 				/*  avoid cases where sscanf is not exact inverse of printf */
 				snprintf(buf, IFNAMSIZ, name, i);
 				if (!strncmp(buf, name_node->name, IFNAMSIZ))
-					set_bit(i, inuse);
+					__set_bit(i, inuse);
 			}
 			if (!sscanf(d->name, name, &i))
 				continue;
@@ -1047,7 +1047,7 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf)
 			/*  avoid cases where sscanf is not exact inverse of printf */
 			snprintf(buf, IFNAMSIZ, name, i);
 			if (!strncmp(buf, d->name, IFNAMSIZ))
-				set_bit(i, inuse);
+				__set_bit(i, inuse);
 		}
 
 		i = find_first_zero_bit(inuse, max_netdevices);
-- 
2.35.0.rc2.247.g8bbb082509-goog