netlink: specs: netdev: clarify the page pool API a little

The phrasing of the page-pool-get doc is very confusing.
It's supposed to highlight that support depends on the driver
doing its part but it sounds like orphaned page pools won't
be visible.

The description of the ifindex is completely wrong.
We move the page pool to loopback and skip the attribute if
ifindex is loopback.

Link: https://lore.kernel.org/20260104084347.5de3a537@kernel.org
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://patch.msgid.link/20260104165232.710460-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index 82bf5cb2617d1851d17f89ae94692d01185e13b0..596c306ce52b8303b20680ff0cd34d4fd9db0e48 100644 (file)
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -142,7 +142,7 @@ attribute-sets:
         name: ifindex
         doc: |
           ifindex of the netdev to which the pool belongs.
-          May be reported as 0 if the page pool was allocated for a netdev
+          May not be reported if the page pool was allocated for a netdev
           which got destroyed already (page pools may outlast their netdevs
           because they wait for all memory to be returned).
         type: u32
@@ -601,7 +601,9 @@ operations:
       name: page-pool-get
       doc: |
         Get / dump information about Page Pools.
-        (Only Page Pools associated with a net_device can be listed.)
+        Only Page Pools associated by the driver with a net_device
+        can be listed. ifindex will not be reported if the net_device
+        no longer exists.
       attribute-set: page-pool
       do:
         request: