devlink: Introduce burst period for health reporter

devlink: Introduce burst period for health reporter

Currently, the devlink health reporter starts the grace period
immediately after handling an error, blocking any further recoveries
until it finished.

However, when a single root cause triggers multiple errors in a short
time frame, it is desirable to treat them as a bulk of errors and to
allow their recoveries, avoiding premature blocking of subsequent
related errors, and reducing the risk of inconsistent or incomplete
error handling.

To address this, introduce a configurable burst period for devlink
health reporter. Start this period when the first error is handled,
and allow recovery attempts for reported errors during this window.
Once burst period expires, begin the grace period to block further
recoveries until it concludes.

Timeline summary:

----|--------|------------------------------/----------------------/--
error is  error is       burst period           grace period
reported  recovered  (recoveries allowed)    (recoveries blocked)

For calculating the burst period duration, use the same
last_recovery_ts as the grace period. Update it on recovery only
when the burst period is inactive (either disabled or at the
first error).

This patch implements the framework for the burst period and
effectively sets its value to 0 at reporter creation, so the current
behavior remains unchanged, which ensures backward compatibility.

A downstream patch will make the burst period configurable.

Signed-off-by: Shahar Shitrit <shshitrit@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250824084354.533182-4-mbloch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>