Re: [PATCH v2 2/3] nvme-pci: Add support for variable IO SQ element size

From: Minwoo Im
Date: Wed Jul 17 2019 - 07:51:52 EST


On 19-07-17 10:45:26, Benjamin Herrenschmidt wrote:
> The size of a submission queue element should always be 6 (64 bytes)
> by spec.
>
> However some controllers such as Apple's are not properly implementing
> the standard and require a different size.
>
> This provides the ground work for the subsequent quirks for these
> controllers.
>
> Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/nvme/host/pci.c | 11 ++++++++---
> include/linux/nvme.h | 1 +
> 2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 8f006638452b..1637677afb78 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -28,7 +28,7 @@
> #include "trace.h"
> #include "nvme.h"
>
> -#define SQ_SIZE(q) ((q)->q_depth * sizeof(struct nvme_command))
> +#define SQ_SIZE(q) ((q)->q_depth << (q)->sqes)
> #define CQ_SIZE(q) ((q)->q_depth * sizeof(struct nvme_completion))
>
> #define SGES_PER_PAGE (PAGE_SIZE / sizeof(struct nvme_sgl_desc))
> @@ -100,6 +100,7 @@ struct nvme_dev {
> unsigned io_queues[HCTX_MAX_TYPES];
> unsigned int num_vecs;
> int q_depth;
> + int io_sqes;
> u32 db_stride;
> void __iomem *bar;
> unsigned long bar_mapped_size;
> @@ -162,7 +163,7 @@ static inline struct nvme_dev *to_nvme_dev(struct nvme_ctrl *ctrl)
> struct nvme_queue {
> struct nvme_dev *dev;
> spinlock_t sq_lock;
> - struct nvme_command *sq_cmds;
> + void *sq_cmds;

It would be great if it can remain the existing data type for the
SQEs... But I'm fine with this also.

It looks good to me.

Reviewed-by: Minwoo Im <minwoo.im.dev@xxxxxxxxx>

Thanks,