nvmet: looks at the passthrough controller when initializing CAP

For a passthru controller make cap initialization dependent on the cap of
the passthru controller, given that multiple Command Set support needs
to be supported by the underlying controller.  For that move the
initialization of CAP later so that it can use the fully initialized
nvmet_ctrl structure.

Fixes: ab5d0b3 (nvmet: add Command Set Identifier support)
Signed-off-by: Adam Manzanares <a.manzanares@samsung.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
[hch: refactored the code a bit to keep it more contained in passthru.c]
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/target/core.c

@@ -1206,6 +1206,9 @@ static void nvmet_init_cap(struct nvmet_ctrl *ctrl)
 	ctrl->cap |= (15ULL << 24);
 	/* maximum queue entries supported: */
 	ctrl->cap |= NVMET_QUEUE_SIZE - 1;
+
+	if (nvmet_passthru_ctrl(ctrl->subsys))
+		nvmet_passthrough_override_cap(ctrl);
 }
 
 struct nvmet_ctrl *nvmet_ctrl_find_get(const char *subsysnqn,
@@ -1363,8 +1366,6 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 		goto out_put_subsystem;
 	mutex_init(&ctrl->lock);
 
-	nvmet_init_cap(ctrl);
-
 	ctrl->port = req->port;
 
 	INIT_WORK(&ctrl->async_event_work, nvmet_async_event_work);
@@ -1378,6 +1379,7 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 
 	kref_init(&ctrl->ref);
 	ctrl->subsys = subsys;
+	nvmet_init_cap(ctrl);
 	WRITE_ONCE(ctrl->aen_enabled, NVMET_AEN_CFG_OPTIONAL);
 
 	ctrl->changed_ns_list = kmalloc_array(NVME_MAX_CHANGED_NAMESPACES,

drivers/nvme/target/nvmet.h

@@ -613,6 +613,8 @@ nvmet_req_passthru_ctrl(struct nvmet_req *req)
 	return nvmet_passthru_ctrl(nvmet_req_subsys(req));
 }
 
+void nvmet_passthrough_override_cap(struct nvmet_ctrl *ctrl);
+
 u16 errno_to_nvme_status(struct nvmet_req *req, int errno);
 u16 nvmet_report_invalid_opcode(struct nvmet_req *req);
 

drivers/nvme/target/passthru.c

@@ -20,6 +20,16 @@ MODULE_IMPORT_NS(NVME_TARGET_PASSTHRU);
  */
 static DEFINE_XARRAY(passthru_subsystems);
 
+void nvmet_passthrough_override_cap(struct nvmet_ctrl *ctrl)
+{
+	/*
+	 * Multiple command set support can only be declared if the underlying
+	 * controller actually supports it.
+	 */
+	if (!nvme_multi_css(ctrl->subsys->passthru_ctrl))
+		ctrl->cap &= ~(1ULL << 43);
+}
+
 static u16 nvmet_passthru_override_id_ctrl(struct nvmet_req *req)
 {
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;