netdev_name_in_use() in dev_prep_valid_name() return -EEXIST makes
more sense if it's not NULL, but dev_alloc_name() should keep the
-ENFILE errno.

There are three callers to dev_prep_valid_name(), the dup_errno
parameter is only for dev_alloc_name, it's not necessary for the other
callers.

Remove the dup_errno parameter in dev_prep_valid_name() and add a
conditional operator to dev_alloc_name(), replace -EEXIST with
-ENFILE.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
---
v2: Make the commit more detailed.
v1: https://lore.kernel.org/all/20240618131743.2690-1-yajun.deng@linux.dev/
---
 net/core/dev.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 0a23d7da7fbc..00e8c785e5ee 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1153,8 +1153,7 @@ static int __dev_alloc_name(struct net *net, const char *name, char *res)
 
 /* Returns negative errno or allocated unit id (see __dev_alloc_name()) */
 static int dev_prep_valid_name(struct net *net, struct net_device *dev,
-			       const char *want_name, char *out_name,
-			       int dup_errno)
+			       const char *want_name, char *out_name)
 {
 	if (!dev_valid_name(want_name))
 		return -EINVAL;
@@ -1163,7 +1162,7 @@ static int dev_prep_valid_name(struct net *net, struct net_device *dev,
 		return __dev_alloc_name(net, want_name, out_name);
 
 	if (netdev_name_in_use(net, want_name))
-		return -dup_errno;
+		return -EEXIST;
 	if (out_name != want_name)
 		strscpy(out_name, want_name, IFNAMSIZ);
 	return 0;
@@ -1185,7 +1184,10 @@ static int dev_prep_valid_name(struct net *net, struct net_device *dev,
 
 int dev_alloc_name(struct net_device *dev, const char *name)
 {
-	return dev_prep_valid_name(dev_net(dev), dev, name, dev->name, ENFILE);
+	int ret;
+
+	ret = dev_prep_valid_name(dev_net(dev), dev, name, dev->name);
+	return ret == -EEXIST ? -ENFILE : ret;
 }
 EXPORT_SYMBOL(dev_alloc_name);
 
@@ -1194,7 +1196,7 @@ static int dev_get_valid_name(struct net *net, struct net_device *dev,
 {
 	int ret;
 
-	ret = dev_prep_valid_name(net, dev, name, dev->name, EEXIST);
+	ret = dev_prep_valid_name(net, dev, name, dev->name);
 	return ret < 0 ? ret : 0;
 }
 
@@ -11446,7 +11448,7 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net,
 		/* We get here if we can't use the current device name */
 		if (!pat)
 			goto out;
-		err = dev_prep_valid_name(net, dev, pat, new_name, EEXIST);
+		err = dev_prep_valid_name(net, dev, pat, new_name);
 		if (err < 0)
 			goto out;
 	}
-- 
2.25.1

On Thu, 27 Jun 2024 21:41:31 +0800 Yajun Deng wrote:
> netdev_name_in_use() in dev_prep_valid_name() return -EEXIST makes
> more sense if it's not NULL, but dev_alloc_name() should keep the
> -ENFILE errno.
> 
> There are three callers to dev_prep_valid_name(), the dup_errno
> parameter is only for dev_alloc_name, it's not necessary for the other
> callers.
> 
> Remove the dup_errno parameter in dev_prep_valid_name() and add a
> conditional operator to dev_alloc_name(), replace -EEXIST with
> -ENFILE.

Let me be more direct this time - I like this code the way I wrote it.
Please leave it be.
-- 
pw-bot: reject