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-rw-r--r--block/blk-flush.c12
-rw-r--r--block/blk-mq.c20
-rw-r--r--block/blk-mq.h2
3 files changed, 24 insertions, 10 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 0e42adc..c41fc19 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -307,16 +307,8 @@ static bool blk_kick_flush(struct request_queue *q)
q->flush_pending_idx ^= 1;
blk_rq_init(q, q->flush_rq);
- if (q->mq_ops) {
- /*
- * Reuse the tag value from the fist waiting request,
- * with blk-mq the tag is generated during request
- * allocation and drivers can rely on it being inside
- * the range they asked for.
- */
- q->flush_rq->mq_ctx = first_rq->mq_ctx;
- q->flush_rq->tag = first_rq->tag;
- }
+ if (q->mq_ops)
+ blk_mq_clone_flush_request(q->flush_rq, first_rq);
q->flush_rq->cmd_type = REQ_TYPE_FS;
q->flush_rq->cmd_flags = WRITE_FLUSH | REQ_FLUSH_SEQ;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index d9d0984..e644fee 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -275,6 +275,26 @@ void blk_mq_free_request(struct request *rq)
__blk_mq_free_request(hctx, ctx, rq);
}
+/*
+ * Clone all relevant state from a request that has been put on hold in
+ * the flush state machine into the preallocated flush request that hangs
+ * off the request queue.
+ *
+ * For a driver the flush request should be invisible, that's why we are
+ * impersonating the original request here.
+ */
+void blk_mq_clone_flush_request(struct request *flush_rq,
+ struct request *orig_rq)
+{
+ struct blk_mq_hw_ctx *hctx =
+ orig_rq->q->mq_ops->map_queue(orig_rq->q, orig_rq->mq_ctx->cpu);
+
+ flush_rq->mq_ctx = orig_rq->mq_ctx;
+ flush_rq->tag = orig_rq->tag;
+ memcpy(blk_mq_rq_to_pdu(flush_rq), blk_mq_rq_to_pdu(orig_rq),
+ hctx->cmd_size);
+}
+
bool blk_mq_end_io_partial(struct request *rq, int error, unsigned int nr_bytes)
{
if (blk_update_request(rq, error, blk_rq_bytes(rq)))
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 238379a..7964dad 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -27,6 +27,8 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
void blk_mq_init_flush(struct request_queue *q);
void blk_mq_drain_queue(struct request_queue *q);
void blk_mq_free_queue(struct request_queue *q);
+void blk_mq_clone_flush_request(struct request *flush_rq,
+ struct request *orig_rq);
/*
* CPU hotplug helpers
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