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authorJakub Kicinski <kuba@kernel.org>2025-03-24 15:45:31 -0700
committerJakub Kicinski <kuba@kernel.org>2025-03-25 10:06:49 -0700
commit0a65dcf6249b75c841b4218426b0d246a805c7e0 (patch)
tree11501e3fe35fdf79950fc41e3f0b5529df61a845 /include
parentnet: explain "protection types" for the instance lock (diff)
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net: designate queue counts as "double ops protected" by instance lock
Drivers which opt into instance lock protection of ops should only call set_real_num_*_queues() under the instance lock. This means that queue counts are double protected (writes are under both rtnl_lock and instance lock, readers under either). Some readers may still be under the rtnl_lock, however, so for now we need double protection of writers. OTOH queue API paths are only under the protection of the instance lock, so we need to validate that the instance is actually locking ops, otherwise the input checks we do against queue count are racy. Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250324224537.248800-6-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/netdevice.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2b91fb96a411..60ef367d8575 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2523,6 +2523,9 @@ struct net_device {
* Double protects:
* @up
*
+ * Double ops protects:
+ * @real_num_rx_queues, @real_num_tx_queues
+ *
* Also protects some fields in struct napi_struct.
*
* Ordering: take after rtnl_lock.