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author | Jakub Kicinski <kuba@kernel.org> | 2023-10-23 08:23:44 -0700 |
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committer | Jakub Kicinski <kuba@kernel.org> | 2023-10-24 13:02:58 -0700 |
commit | 7ad17b04dc7bdcdd1f85e460c38da55b0afa2422 (patch) | |
tree | d9a92c01c0d5e70eba770dc789bbf20e09de6052 /net/core/dev.c | |
parent | 9a810468126c846299d867f73dd7053064c29be1 (diff) | |
download | linux-7ad17b04dc7bdcdd1f85e460c38da55b0afa2422.tar.gz linux-7ad17b04dc7bdcdd1f85e460c38da55b0afa2422.tar.bz2 linux-7ad17b04dc7bdcdd1f85e460c38da55b0afa2422.zip |
net: trust the bitmap in __dev_alloc_name()
Prior to restructuring __dev_alloc_name() handled both printf
and non-printf names. In a clever attempt at code reuse it
always prints the name into a buffer and checks if it's
a duplicate.
Trust the bitmap, and return an error if its full.
This shrinks the possible ID space by one from 32K to 32K - 1,
as previously the max value would have been tried as a valid ID.
It seems very unlikely that anyone would care as we heard
no requests to increase the max beyond 32k.
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231023152346.3639749-5-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core/dev.c')
-rw-r--r-- | net/core/dev.c | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index bbfb02b4a228..d2698b4bbad4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1119,18 +1119,11 @@ static int __dev_alloc_name(struct net *net, const char *name, char *res) i = find_first_zero_bit(inuse, max_netdevices); bitmap_free(inuse); + if (i == max_netdevices) + return -ENFILE; - snprintf(buf, IFNAMSIZ, name, i); - if (!netdev_name_in_use(net, buf)) { - strscpy(res, buf, IFNAMSIZ); - return i; - } - - /* It is possible to run out of possible slots - * when the name is long and there isn't enough space left - * for the digits, or if all bits are used. - */ - return -ENFILE; + snprintf(res, IFNAMSIZ, name, i); + return i; } /* Returns negative errno or allocated unit id (see __dev_alloc_name()) */ |