[PATCH net-next 2/7] devlink: Rework devlink health reporter destructor

[Moshe Shemesh]

From: Vladyslav Tarasiuk <vladysl...@mellanox.com>

Devlink keeps its own reference to every reporter in a list and inits
refcount to 1 upon reporter's creation. Existing destructor waits to
free the memory indefinitely using msleep() until all references except
devlink's own are put.

Rework this mechanism by moving memory free routine to a separate
function, which is called when the last reporter reference is put.

Besides, it allows to call __devlink_health_reporter_destroy() while
locked on a reporters list mutex in symmetry to
__devlink_health_reporter_create(), which is required in follow-up
patch.

Signed-off-by: Vladyslav Tarasiuk <vladysl...@mellanox.com>
Reviewed-by: Moshe Shemesh <mo...@mellanox.com>
Reviewed-by: Jiri Pirko <j...@mellanox.com>
---
 net/core/devlink.c | 37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index dfd7fe2..dcf8006 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -5353,6 +5353,29 @@ struct devlink_health_reporter *
 }
 EXPORT_SYMBOL_GPL(devlink_health_reporter_create);
 
+static void
+devlink_health_reporter_free(struct devlink_health_reporter *reporter)
+{
+       mutex_destroy(&reporter->dump_lock);
+       if (reporter->dump_fmsg)
+               devlink_fmsg_free(reporter->dump_fmsg);
+       kfree(reporter);
+}
+
+static void
+devlink_health_reporter_put(struct devlink_health_reporter *reporter)
+{
+       if (refcount_dec_and_test(&reporter->refcount))
+               devlink_health_reporter_free(reporter);
+}
+
+static void
+__devlink_health_reporter_destroy(struct devlink_health_reporter *reporter)
+{
+       list_del(&reporter->list);
+       devlink_health_reporter_put(reporter);
+}
+
 /**
  *     devlink_health_reporter_destroy - destroy devlink health reporter
  *
@@ -5362,14 +5385,8 @@ struct devlink_health_reporter *
 devlink_health_reporter_destroy(struct devlink_health_reporter *reporter)
 {
        mutex_lock(&reporter->devlink->reporters_lock);
-       list_del(&reporter->list);
+       __devlink_health_reporter_destroy(reporter);
        mutex_unlock(&reporter->devlink->reporters_lock);
-       while (refcount_read(&reporter->refcount) > 1)
-               msleep(100);
-       mutex_destroy(&reporter->dump_lock);
-       if (reporter->dump_fmsg)
-               devlink_fmsg_free(reporter->dump_fmsg);
-       kfree(reporter);
 }
 EXPORT_SYMBOL_GPL(devlink_health_reporter_destroy);
 
@@ -5639,12 +5656,6 @@ int devlink_health_report(struct devlink_health_reporter 
*reporter,
        return NULL;
 }
 
-static void
-devlink_health_reporter_put(struct devlink_health_reporter *reporter)
-{
-       refcount_dec(&reporter->refcount);
-}
-
 void
 devlink_health_reporter_state_update(struct devlink_health_reporter *reporter,
                                     enum devlink_health_reporter_state state)
-- 
1.8.3.1