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-rw-r--r--kernel/locking/rtmutex.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 78a6c4a223c1..b73cd7c87551 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -22,6 +22,7 @@
#include <linux/sched/deadline.h>
#include <linux/timer.h>
#include <linux/ww_mutex.h>
+#include <linux/blkdev.h>
#include "rtmutex_common.h"
@@ -1968,6 +1969,15 @@ rt_mutex_fastlock(struct rt_mutex *lock, int state,
if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
return 0;
+ /*
+ * If rt_mutex blocks, the function sched_submit_work will not call
+ * blk_schedule_flush_plug (because tsk_is_pi_blocked would be true).
+ * We must call blk_schedule_flush_plug here, if we don't call it,
+ * a deadlock in device mapper may happen.
+ */
+ if (unlikely(blk_needs_flush_plug(current)))
+ blk_schedule_flush_plug(current);
+
return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK, ww_ctx);
}
@@ -1985,6 +1995,9 @@ rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
return 0;
+ if (unlikely(blk_needs_flush_plug(current)))
+ blk_schedule_flush_plug(current);
+
return slowfn(lock, state, timeout, chwalk, ww_ctx);
}