[PATCH v3 4/4] drivers: lustre: obdclass: check result of register_shrinker()

[Aliaksei Karaliou]

lu_global_init() does not check result of register_shrinker()
which was tagged __must_check recently, reported by sparse.
Patch also fixes missed cleanup of resources allocated prior to
register_shrinker() invocation and not freed after any failure.

Signed-off-by: Aliaksei Karaliou <akaraliou.dev at gmail.com>
---
 drivers/staging/lustre/lustre/obdclass/lu_object.c | 27 ++++++++++++++++++----
 1 file changed, 22 insertions(+), 5 deletions(-)

v3: Also address incomplate resource cleanup, noticed by Dan Carpenter.

diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
index b938a3f9d50a..8e2e6b89e494 100644
--- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
@@ -1932,8 +1932,10 @@ int lu_global_init(void)
 
 	LU_CONTEXT_KEY_INIT(&lu_global_key);
 	result = lu_context_key_register(&lu_global_key);
-	if (result != 0)
+	if (result != 0) {
+		lu_ref_global_fini();
 		return result;
+	}
 
 	/*
 	 * At this level, we don't know what tags are needed, so allocate them
@@ -1943,17 +1945,31 @@ int lu_global_init(void)
 	down_write(&lu_sites_guard);
 	result = lu_env_init(&lu_shrink_env, LCT_SHRINKER);
 	up_write(&lu_sites_guard);
-	if (result != 0)
+	if (result != 0) {
+		lu_context_key_degister(&lu_global_key);
+		lu_ref_global_fini();
 		return result;
+	}
 
 	/*
 	 * seeks estimation: 3 seeks to read a record from oi, one to read
 	 * inode, one for ea. Unfortunately setting this high value results in
 	 * lu_object/inode cache consuming all the memory.
 	 */
-	register_shrinker(&lu_site_shrinker);
+	result = register_shrinker(&lu_site_shrinker);
+	if (result != 0) {
+		/* Order explained in lu_global_fini(). */
+		lu_context_key_degister(&lu_global_key);
 
-	return result;
+		down_write(&lu_sites_guard);
+		lu_env_fini(&lu_shrink_env);
+		up_write(&lu_sites_guard);
+
+		lu_ref_global_fini();
+		return result;
+	}
+
+	return 0;
 }
 
 /**
@@ -1961,7 +1977,8 @@ int lu_global_init(void)
  */
 void lu_global_fini(void)
 {
-	unregister_shrinker(&lu_site_shrinker);
+	if (lu_site_shrinker.nr_deferred)
+		unregister_shrinker(&lu_site_shrinker);
 	lu_context_key_degister(&lu_global_key);
 
 	/*
-- 
2.11.0