diff mbox series

[net-next,6/9] docs: net: document netdev notifier expectations

Message ID 20250325213056.332902-7-sdf@fomichev.me (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: hold instance lock during NETDEV_UP/REGISTER/UNREGISTER | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 3 maintainers not CCed: corbet@lwn.net linux-doc@vger.kernel.org horms@kernel.org
netdev/build_clang fail Errors and warnings before: 5 this patch: 5
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 5 this patch: 5
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 24 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Stanislav Fomichev March 25, 2025, 9:30 p.m. UTC
We don't have a consistent state yet, but document where we think
we are and where we wanna be.

Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
 Documentation/networking/netdevices.rst | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
diff mbox series

Patch

diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst
index ebb868f50ac2..89337cfec36e 100644
--- a/Documentation/networking/netdevices.rst
+++ b/Documentation/networking/netdevices.rst
@@ -343,6 +343,24 @@  there are two sets of interfaces: ``dev_xxx`` and ``netif_xxx`` (e.g.,
 acquiring the instance lock themselves, while the ``netif_xxx`` functions
 assume that the driver has already acquired the instance lock.
 
+Notifiers and netdev instance lock
+==================================
+
+For device drivers that implement shaping or queue management APIs,
+some of the notifiers (``enum netdev_cmd``) are running under the netdev
+instance lock.
+
+Currently only the following notifiers are running under the instance lock:
+* ``NETDEV_REGISTER``
+* ``NETDEV_UP``
+* ``NETDEV_UNREGISTER``
+
+There are no clear expectations for the remaining notifiers. Notifiers not on
+the list may run with or without the instance lock, potentially even invoking
+the same notifier type with and without the lock from different code paths.
+The goal is to eventually ensure that all (or most, with a few documented
+exceptions) notifiers run under the instance lock.
+
 NETDEV_INTERNAL symbol namespace
 ================================