[dm-devel] [PATCH v3 10/19] nvme: Move NVMe and Block PR types to an array

[Keith Busch]

On Wed, Oct 26, 2022 at 06:19:36PM -0500, Mike Christie wrote:
> For Reservation Report support we need to also convert from the NVMe spec
> PR type back to the block PR definition. This moves us to an array, so in
> the next patch we can add another helper to do the conversion without
> having to manage 2 switches.
> 
> Signed-off-by: Mike Christie <michael.christie at oracle.com>
> ---
>  drivers/nvme/host/pr.c | 42 +++++++++++++++++++++++-------------------
>  include/linux/nvme.h   |  9 +++++++++
>  2 files changed, 32 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/nvme/host/pr.c b/drivers/nvme/host/pr.c
> index df7eb2440c67..5c4611d15d9c 100644
> --- a/drivers/nvme/host/pr.c
> +++ b/drivers/nvme/host/pr.c
> @@ -6,24 +6,28 @@
>  
>  #include "nvme.h"
>  
> -static char nvme_pr_type(enum pr_type type)
> +static const struct {
> +	enum nvme_pr_type	nvme_type;
> +	enum pr_type		blk_type;
> +} nvme_pr_types[] = {
> +	{ NVME_PR_WRITE_EXCLUSIVE, PR_WRITE_EXCLUSIVE },
> +	{ NVME_PR_EXCLUSIVE_ACCESS, PR_EXCLUSIVE_ACCESS },
> +	{ NVME_PR_WRITE_EXCLUSIVE_REG_ONLY, PR_WRITE_EXCLUSIVE_REG_ONLY },
> +	{ NVME_PR_EXCLUSIVE_ACCESS_REG_ONLY, PR_EXCLUSIVE_ACCESS_REG_ONLY },
> +	{ NVME_PR_WRITE_EXCLUSIVE_ALL_REGS, PR_WRITE_EXCLUSIVE_ALL_REGS },
> +	{ NVME_PR_EXCLUSIVE_ACCESS_ALL_REGS, PR_EXCLUSIVE_ACCESS_ALL_REGS },
> +};

Wouldn't it be easier to use the block type as the array index to avoid
the whole looped lookup?

  enum nvme_pr_type types[] = {
	.PR_WRITE_EXCLUSIVE = NVME_PR_WRITE_EXCLUSIVE,
	.PR_EXCLUSIVE_ACCESS  = NVME_PR_EXCLUSIVE_ACCESS,
        ...
  };

?