| Message ID | 20231020011856.3244410-3-kuba@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: deduplicate netdev name allocation | expand |
Fri, Oct 20, 2023 at 03:18:52AM CEST, kuba@kernel.org wrote: >__dev_alloc_name() handles both the sprintf and non-sprintf >target names. This complicates the code. > >dev_prep_valid_name() already handles the non-sprintf case, >before calling __dev_alloc_name(), make the only other caller >also go thru dev_prep_valid_name(). This way we can drop >the non-sprintf handling in __dev_alloc_name() in one of >the next changes. > >commit 55a5ec9b7710 ("Revert "net: core: dev_get_valid_name is now the same as dev_alloc_name_ns"") and >commit 029b6d140550 ("Revert "net: core: maybe return -EEXIST in __dev_alloc_name"") >tell us that we can't start returning -EEXIST from dev_alloc_name() >on name duplicates. Bite the bullet and pass the expected errno to >dev_prep_valid_name(). > >dev_prep_valid_name() must now propagate out the allocated id >for printf names. > >Signed-off-by: Jakub Kicinski <kuba@kernel.org> >--- > net/core/dev.c | 20 +++++++++++--------- > 1 file changed, 11 insertions(+), 9 deletions(-) > >diff --git a/net/core/dev.c b/net/core/dev.c >index 874c7daa81f5..004e9f26b160 100644 >--- a/net/core/dev.c >+++ b/net/core/dev.c >@@ -1137,19 +1137,18 @@ static int __dev_alloc_name(struct net *net, const char *name, char *res) > return -ENFILE; > } > >+/* 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) >+ const char *want_name, char *out_name, >+ int dup_errno) > { >- int ret; >- > if (!dev_valid_name(want_name)) > return -EINVAL; > > if (strchr(want_name, '%')) { >- ret = __dev_alloc_name(net, want_name, out_name); >- return ret < 0 ? ret : 0; >+ return __dev_alloc_name(net, want_name, out_name); > } else if (netdev_name_in_use(net, want_name)) { >- return -EEXIST; >+ return -dup_errno; > } else if (out_name != want_name) { > strscpy(out_name, want_name, IFNAMSIZ); > } >@@ -1173,14 +1172,17 @@ 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_alloc_name(dev_net(dev), name, dev->name); >+ return dev_prep_valid_name(dev_net(dev), dev, name, dev->name, ENFILE); > } > EXPORT_SYMBOL(dev_alloc_name); > > static int dev_get_valid_name(struct net *net, struct net_device *dev, > const char *name) > { >- return dev_prep_valid_name(net, dev, name, dev->name); >+ int ret; >+ >+ ret = dev_prep_valid_name(net, dev, name, dev->name, EEXIST); >+ return ret < 0 ? ret : 0; Why can't you just return dev_prep_valid_name() ? No caller seems to care about ret > 0 > } > > /** >@@ -11118,7 +11120,7 @@ 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); >+ err = dev_prep_valid_name(net, dev, pat, new_name, EEXIST); > if (err < 0) > goto out; > } >-- >2.41.0 >
On Fri, 20 Oct 2023 12:24:57 +0200 Jiri Pirko wrote: > > static int dev_get_valid_name(struct net *net, struct net_device *dev, > > const char *name) > > { > >- return dev_prep_valid_name(net, dev, name, dev->name); > >+ int ret; > >+ > >+ ret = dev_prep_valid_name(net, dev, name, dev->name, EEXIST); > >+ return ret < 0 ? ret : 0; > > Why can't you just return dev_prep_valid_name() ? > > No caller seems to care about ret > 0 AFACT dev_change_name() has some weird code that ends up return the value all the way to the ioctl and user space. Note that it has both err and ret variables :S
Fri, Oct 20, 2023 at 09:01:49PM CEST, kuba@kernel.org wrote: >On Fri, 20 Oct 2023 12:24:57 +0200 Jiri Pirko wrote: >> > static int dev_get_valid_name(struct net *net, struct net_device *dev, >> > const char *name) >> > { >> >- return dev_prep_valid_name(net, dev, name, dev->name); >> >+ int ret; >> >+ >> >+ ret = dev_prep_valid_name(net, dev, name, dev->name, EEXIST); >> >+ return ret < 0 ? ret : 0; >> >> Why can't you just return dev_prep_valid_name() ? >> >> No caller seems to care about ret > 0 > >AFACT dev_change_name() has some weird code that ends up return >the value all the way to the ioctl and user space. Note that it >has both err and ret variables :S Ah, blah. Guess we are stick to this crap :/ Reviewed-by: Jiri Pirko <jiri@nvidia.com>
diff --git a/net/core/dev.c b/net/core/dev.c index 874c7daa81f5..004e9f26b160 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1137,19 +1137,18 @@ static int __dev_alloc_name(struct net *net, const char *name, char *res) return -ENFILE; } +/* 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) + const char *want_name, char *out_name, + int dup_errno) { - int ret; - if (!dev_valid_name(want_name)) return -EINVAL; if (strchr(want_name, '%')) { - ret = __dev_alloc_name(net, want_name, out_name); - return ret < 0 ? ret : 0; + return __dev_alloc_name(net, want_name, out_name); } else if (netdev_name_in_use(net, want_name)) { - return -EEXIST; + return -dup_errno; } else if (out_name != want_name) { strscpy(out_name, want_name, IFNAMSIZ); } @@ -1173,14 +1172,17 @@ 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_alloc_name(dev_net(dev), name, dev->name); + return dev_prep_valid_name(dev_net(dev), dev, name, dev->name, ENFILE); } EXPORT_SYMBOL(dev_alloc_name); static int dev_get_valid_name(struct net *net, struct net_device *dev, const char *name) { - return dev_prep_valid_name(net, dev, name, dev->name); + int ret; + + ret = dev_prep_valid_name(net, dev, name, dev->name, EEXIST); + return ret < 0 ? ret : 0; } /** @@ -11118,7 +11120,7 @@ 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); + err = dev_prep_valid_name(net, dev, pat, new_name, EEXIST); if (err < 0) goto out; }
__dev_alloc_name() handles both the sprintf and non-sprintf target names. This complicates the code. dev_prep_valid_name() already handles the non-sprintf case, before calling __dev_alloc_name(), make the only other caller also go thru dev_prep_valid_name(). This way we can drop the non-sprintf handling in __dev_alloc_name() in one of the next changes. commit 55a5ec9b7710 ("Revert "net: core: dev_get_valid_name is now the same as dev_alloc_name_ns"") and commit 029b6d140550 ("Revert "net: core: maybe return -EEXIST in __dev_alloc_name"") tell us that we can't start returning -EEXIST from dev_alloc_name() on name duplicates. Bite the bullet and pass the expected errno to dev_prep_valid_name(). dev_prep_valid_name() must now propagate out the allocated id for printf names. Signed-off-by: Jakub Kicinski <kuba@kernel.org> --- net/core/dev.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)