Re: [PATCH 2/2] nvmet: use passthru cntrl in nvmet_init_cap

[Adam Manzanares]

On Fri, Aug 27, 2021 at 08:17:37AM +0200, hch@xxxxxx wrote:
> Technically this looks good, but the core target code should not have
> to poke into the host side data structures.  Does this version still look
> good to you?

Yup looks good, thanks for the help cleaning it up.

> 
> ---
> From c5777caf1562df35150a71e5c91c5b272956beee Mon Sep 17 00:00:00 2001
> From: Adam Manzanares <a.manzanares@xxxxxxxxxxx>
> Date: Thu, 26 Aug 2021 21:15:45 +0000
> Subject: 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: ab5d0b38c047 (nvmet: add Command Set Identifier support)
> Signed-off-by: Adam Manzanares <a.manzanares@xxxxxxxxxxx>
> Reviewed-by: Keith Busch <kbusch@xxxxxxxxxx>
> [hch: refactored the code a bit to keep it more contained in passthru.c]
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>  drivers/nvme/target/core.c     |  6 ++++--
>  drivers/nvme/target/nvmet.h    |  2 ++
>  drivers/nvme/target/passthru.c | 10 ++++++++++
>  3 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
> index 66d05eecc2a9..11c44706dc2d 100644
> --- a/drivers/nvme/target/core.c
> +++ b/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,
> diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
> index 06dd3d537f07..183119607968 100644
> --- a/drivers/nvme/target/nvmet.h
> +++ b/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);
>  
> diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
> index 225cd1ffbe45..8784c487e462 100644
> --- a/drivers/nvme/target/passthru.c
> +++ b/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;
> -- 
> 2.30.2
>