From: NeilBrown <neilb@suse.com>
Date: Tue, 1 Oct 2019 18:12:23 +0000 (-0400)
Subject: LU-10467 lov: use wait_event() in lov_subobject_kill()
X-Git-Tag: 2.13.51~175
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=c0894d1d326701620c0b5538155053e7d93e719d

LU-10467 lov: use wait_event() in lov_subobject_kill()

lov_subobject_kill() has an open-coded version
of wait_event(). Change it to use the macro.

There is no need to take a spinlock just to check if a variable
have changed value. If there was, the first test would be protected too.

"lti_waiter" now has no users and can be removed from lov_thread_info.

Change-Id: Ic1126fc500c03c48c4426171e98590ef6dce3098
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-on: https://review.whamcloud.com/36343
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---

diff --git a/lustre/lov/lov_cl_internal.h b/lustre/lov/lov_cl_internal.h
index b811451..7768625 100644
--- a/lustre/lov/lov_cl_internal.h
+++ b/lustre/lov/lov_cl_internal.h
@@ -471,7 +471,6 @@ struct lov_thread_info {
 	struct ost_lvb          lti_lvb;
 	struct cl_2queue        lti_cl2q;
 	struct cl_page_list     lti_plist;
-	wait_queue_entry_t      lti_waiter;
 };
 
 /**
diff --git a/lustre/lov/lov_object.c b/lustre/lov/lov_object.c
index 64c99b3..c41a853 100644
--- a/lustre/lov/lov_object.c
+++ b/lustre/lov/lov_object.c
@@ -284,7 +284,6 @@ static void lov_subobject_kill(const struct lu_env *env, struct lov_object *lov,
 	struct cl_object        *sub;
 	struct lu_site          *site;
 	wait_queue_head_t *wq;
-	wait_queue_entry_t *waiter;
 
         LASSERT(r0->lo_sub[idx] == los);
 
@@ -299,27 +298,7 @@ static void lov_subobject_kill(const struct lu_env *env, struct lov_object *lov,
 
 	/* ... wait until it is actually destroyed---sub-object clears its
 	 * ->lo_sub[] slot in lovsub_object_free() */
-	if (r0->lo_sub[idx] == los) {
-		waiter = &lov_env_info(env)->lti_waiter;
-		init_waitqueue_entry(waiter, current);
-		add_wait_queue(wq, waiter);
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		while (1) {
-			/* this wait-queue is signaled at the end of
-			 * lu_object_free(). */
-			set_current_state(TASK_UNINTERRUPTIBLE);
-			spin_lock(&r0->lo_sub_lock);
-			if (r0->lo_sub[idx] == los) {
-				spin_unlock(&r0->lo_sub_lock);
-				schedule();
-			} else {
-				spin_unlock(&r0->lo_sub_lock);
-				set_current_state(TASK_RUNNING);
-				break;
-			}
-		}
-		remove_wait_queue(wq, waiter);
-	}
+	wait_event(*wq, r0->lo_sub[idx] != los);
 	LASSERT(r0->lo_sub[idx] == NULL);
 }