btrfs: zstd: ensure reclaim timer is properly cleaned up

dennisszhou · kdave · commit d3865159ac78 · 2019-02-27T17:45:04.000+01:00
The timer function, zstd_reclaim_timer_fn(), reschedules itself under
certain conditions. When cleaning up, take the lock and remove all
workspaces. This prevents the timer from rearming itself. Lastly, switch
to del_timer_sync() to ensure that the timer function can't trigger as
we're unloading.

Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
Reviewed-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
@@ -195,8 +195,7 @@ static void zstd_cleanup_workspace_manager(void)
 	struct workspace *workspace;
 	int i;
 
-	del_timer(&wsm.timer);
-
+	spin_lock(&wsm.lock);
 	for (i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++) {
 		while (!list_empty(&wsm.idle_ws[i])) {
 			workspace = container_of(wsm.idle_ws[i].next,
@@ -206,6 +205,9 @@ static void zstd_cleanup_workspace_manager(void)
 			wsm.ops->free_workspace(&workspace->list);
 		}
 	}
+	spin_unlock(&wsm.lock);
+
+	del_timer_sync(&wsm.timer);
 }
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -195,8 +195,7 @@ static void zstd_cleanup_workspace_manager(void)`
`195`	`195`	`struct workspace *workspace;`
`196`	`196`	`int i;`
`197`	`197`
`198`		`- del_timer(&wsm.timer);`
`199`		`-`
	`198`	`+ spin_lock(&wsm.lock);`
`200`	`199`	`for (i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++) {`
`201`	`200`	`while (!list_empty(&wsm.idle_ws[i])) {`
`202`	`201`	`workspace = container_of(wsm.idle_ws[i].next,`
`@@ -206,6 +205,9 @@ static void zstd_cleanup_workspace_manager(void)`
`206`	`205`	`wsm.ops->free_workspace(&workspace->list);`
`207`	`206`	`}`
`208`	`207`	`}`
	`208`	`+ spin_unlock(&wsm.lock);`
	`209`	`+`
	`210`	`+ del_timer_sync(&wsm.timer);`
`209`	`211`	`}`
`210`	`212`
`211`	`213`	`/*`