diff mbox series

[net-next,v3,5/7] Documentation: devlink: add nested instance section

Message ID 20231013121029.353351-6-jiri@resnulli.us (mailing list archive)
State Accepted
Commit b6f23b319aadae50a03b06c3067bc7e4a659e43b
Delegated to: Netdev Maintainers
Headers show
Series devlink: fix a deadlock when taking devlink instance lock while holding RTNL lock | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
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 success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers warning 2 maintainers not CCed: linux-doc@vger.kernel.org corbet@lwn.net
netdev/build_clang success Errors and warnings before: 9 this patch: 9
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 success Errors and warnings before: 9 this patch: 9
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 30 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jiri Pirko Oct. 13, 2023, 12:10 p.m. UTC 
From: Jiri Pirko <jiri@nvidia.com>

Add a part talking about nested devlink instances describing
the helpers and locking ordering.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
v2->v3:
- new patch
---
 Documentation/networking/devlink/index.rst | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)

Comments

Simon Horman Oct. 17, 2023, 8:52 a.m. UTC | #1 
On Fri, Oct 13, 2023 at 02:10:27PM +0200, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@nvidia.com>
> 
> Add a part talking about nested devlink instances describing
> the helpers and locking ordering.
> 
> Signed-off-by: Jiri Pirko <jiri@nvidia.com>

Reviewed-by: Simon Horman <horms@kernel.org>
diff mbox series

Patch

diff --git a/Documentation/networking/devlink/index.rst b/Documentation/networking/devlink/index.rst
index b49749e2b9a6..52e52a1b603d 100644
--- a/Documentation/networking/devlink/index.rst
+++ b/Documentation/networking/devlink/index.rst
@@ -18,6 +18,30 @@  netlink commands.
 
 Drivers are encouraged to use the devlink instance lock for their own needs.
 
+Nested instances
+----------------
+
+Some objects, like linecards or port functions, could have another
+devlink instances created underneath. In that case, drivers should make
+sure to respect following rules:
+
+ - Lock ordering should be maintained. If driver needs to take instance
+   lock of both nested and parent instances at the same time, devlink
+   instance lock of the parent instance should be taken first, only then
+   instance lock of the nested instance could be taken.
+ - Driver should use object-specific helpers to setup the
+   nested relationship:
+
+   - ``devl_nested_devlink_set()`` - called to setup devlink -> nested
+     devlink relationship (could be user for multiple nested instances.
+   - ``devl_port_fn_devlink_set()`` - called to setup port function ->
+     nested devlink relationship.
+   - ``devlink_linecard_nested_dl_set()`` - called to setup linecard ->
+     nested devlink relationship.
+
+The nested devlink info is exposed to the userspace over object-specific
+attributes of devlink netlink.
+
 Interface documentation
 -----------------------