[PATCH 3/7] nvmet: allow async passthrough of commands that change logical block contents

[Christoph Hellwig <hch@lst.de>]

Mask out the logical block change effect to allow to keep supporting
passthrough for Write commands once I/O Command effects are properly
propagated.

Fixes: c1fef73f793b ("nvmet: add passthru code to process commands")
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvme/target/passthru.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
index 79af5140af8bfe..ad80ba61c42236 100644
--- a/drivers/nvme/target/passthru.c
+++ b/drivers/nvme/target/passthru.c
@@ -295,7 +295,6 @@ static void nvmet_passthru_execute_cmd(struct nvmet_req *req)
 	struct nvme_ns *ns = NULL;
 	struct request *rq = NULL;
 	unsigned int timeout;
-	u32 effects;
 	u16 status;
 	int ret;
 
@@ -334,14 +333,16 @@ static void nvmet_passthru_execute_cmd(struct nvmet_req *req)
 	}
 
 	/*
-	 * If there are effects for the command we are about to execute, or
-	 * an end_req function we need to use nvme_execute_passthru_rq()
-	 * synchronously in a work item seeing the end_req function and
-	 * nvme_passthru_end() can't be called in the request done callback
-	 * which is typically in interrupt context.
+	 * If there are any non-trivial effects for the command we are about to
+	 * execute, call nvme_execute_passthru_rq in a workqueue, so that the
+	 * effects can be properly handled by the calls to nvme_passthru_start
+	 * and nvme_passthru_end.
 	 */
-	effects = nvme_command_effects(ctrl, ns, req->cmd->common.opcode);
-	if (req->p.use_workqueue || effects) {
+	if (nvme_command_effects(ctrl, ns, req->cmd->common.opcode) &
+	    ~NVME_CMD_EFFECTS_LBCC)
+		req->p.use_workqueue = true;
+
+	if (req->p.use_workqueue) {
 		INIT_WORK(&req->p.work, nvmet_passthru_execute_cmd_work);
 		req->p.rq = rq;
 		queue_work(nvmet_wq, &req->p.work);
-- 
2.35.1