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Diffstat (limited to 'block/blk-flush.c')
-rw-r--r--block/blk-flush.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 2d162bd840d3..491eb30a242d 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -123,7 +123,7 @@ static void blk_flush_restore_request(struct request *rq)
/* make @rq a normal request */
rq->cmd_flags &= ~REQ_FLUSH_SEQ;
- rq->end_io = NULL;
+ rq->end_io = rq->flush.saved_end_io;
}
/**
@@ -301,9 +301,6 @@ void blk_insert_flush(struct request *rq)
unsigned int fflags = q->flush_flags; /* may change, cache */
unsigned int policy = blk_flush_policy(fflags, rq);
- BUG_ON(rq->end_io);
- BUG_ON(!rq->bio || rq->bio != rq->biotail);
-
/*
* @policy now records what operations need to be done. Adjust
* REQ_FLUSH and FUA for the driver.
@@ -313,6 +310,19 @@ void blk_insert_flush(struct request *rq)
rq->cmd_flags &= ~REQ_FUA;
/*
+ * An empty flush handed down from a stacking driver may
+ * translate into nothing if the underlying device does not
+ * advertise a write-back cache. In this case, simply
+ * complete the request.
+ */
+ if (!policy) {
+ __blk_end_bidi_request(rq, 0, 0, 0);
+ return;
+ }
+
+ BUG_ON(!rq->bio || rq->bio != rq->biotail);
+
+ /*
* If there's data but flush is not necessary, the request can be
* processed directly without going through flush machinery. Queue
* for normal execution.
@@ -320,6 +330,7 @@ void blk_insert_flush(struct request *rq)
if ((policy & REQ_FSEQ_DATA) &&
!(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) {
list_add_tail(&rq->queuelist, &q->queue_head);
+ blk_run_queue_async(q);
return;
}
@@ -330,6 +341,7 @@ void blk_insert_flush(struct request *rq)
memset(&rq->flush, 0, sizeof(rq->flush));
INIT_LIST_HEAD(&rq->flush.list);
rq->cmd_flags |= REQ_FLUSH_SEQ;
+ rq->flush.saved_end_io = rq->end_io; /* Usually NULL */
rq->end_io = flush_data_end_io;
blk_flush_complete_seq(rq, REQ_FSEQ_ACTIONS & ~policy, 0);