Re: [ndctl PATCH 09/15] cxl/region: Make ways an integer argument

["Verma, Vishal L" <vishal.l.verma@intel.com>]

On Sun, 2022-11-06 at 15:47 -0800, Dan Williams wrote:
> Since --ways does not take a unit value like --size, just make it an
> integer argument directly and skip the hand coded conversion.

Ah I had gone back and forth between using an int vs. unsigned. I had
gone with unsigned because the kernel treats it as an unsigned too
behind the sysfs ABI. But I guess in practice it doesn't matter, since
the values are clamped to [256, 16K]. Certainly using an int here makes
things cleaner!

> 
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  cxl/region.c |   41 +++++++++++++++++++----------------------
>  1 file changed, 19 insertions(+), 22 deletions(-)
> 
> diff --git a/cxl/region.c b/cxl/region.c
> index 334fcc291de7..494da5139c05 100644
> --- a/cxl/region.c
> +++ b/cxl/region.c
> @@ -21,21 +21,23 @@
>  static struct region_params {
>         const char *bus;
>         const char *size;
> -       const char *ways;
>         const char *granularity;
>         const char *type;
>         const char *root_decoder;
>         const char *region;
> +       int ways;
>         bool memdevs;
>         bool force;
>         bool human;
>         bool debug;
> -} param;
> +} param = {
> +       .ways = INT_MAX,
> +};
>  
>  struct parsed_params {
>         u64 size;
>         u64 ep_min_size;
> -       unsigned int ways;
> +       int ways;
>         unsigned int granularity;
>         const char **targets;
>         int num_targets;
> @@ -63,9 +65,8 @@ OPT_BOOLEAN(0, "debug", &param.debug, "turn on
> debug")
>  OPT_STRING('s', "size", &param.size, \
>            "size in bytes or with a K/M/G etc. suffix", \
>            "total size desired for the resulting region."), \
> -OPT_STRING('w', "ways", &param.ways, \
> -          "number of interleave ways", \
> -          "number of memdevs participating in the regions interleave
> set"), \
> +OPT_INTEGER('w', "ways", &param.ways, \
> +           "number of memdevs participating in the regions
> interleave set"), \
>  OPT_STRING('g', "granularity", \
>            &param.granularity, "interleave granularity", \
>            "granularity of the interleave set"), \
> @@ -126,15 +127,11 @@ static int parse_create_options(int argc, const
> char **argv,
>                 }
>         }
>  
> -       if (param.ways) {
> -               unsigned long ways = strtoul(param.ways, NULL, 0);
> -
> -               if (ways == ULONG_MAX || (int)ways <= 0) {
> -                       log_err(&rl, "Invalid interleave ways: %s\n",
> -                               param.ways);
> -                       return -EINVAL;
> -               }
> -               p->ways = ways;
> +       if (param.ways <= 0) {
> +               log_err(&rl, "Invalid interleave ways: %d\n",
> param.ways);
> +               return -EINVAL;
> +       } else if (param.ways < INT_MAX) {
> +               p->ways = param.ways;
>         } else if (argc) {
>                 p->ways = argc;
>         } else {
> @@ -155,13 +152,13 @@ static int parse_create_options(int argc, const
> char **argv,
>         }
>  
>  
> -       if (argc > (int)p->ways) {
> +       if (argc > p->ways) {
>                 for (i = p->ways; i < argc; i++)
>                         log_err(&rl, "extra argument: %s\n", p-
> >targets[i]);
>                 return -EINVAL;
>         }
>  
> -       if (argc < (int)p->ways) {
> +       if (argc < p->ways) {
>                 log_err(&rl,
>                         "too few target arguments (%d) for interleave
> ways (%u)\n",
>                         argc, p->ways);
> @@ -253,7 +250,7 @@ static bool validate_memdev(struct cxl_memdev
> *memdev, const char *target,
>  
>  static int validate_config_memdevs(struct cxl_ctx *ctx, struct
> parsed_params *p)
>  {
> -       unsigned int i, matched = 0;
> +       int i, matched = 0;
>  
>         for (i = 0; i < p->ways; i++) {
>                 struct cxl_memdev *memdev;
> @@ -393,7 +390,8 @@ static int
> cxl_region_determine_granularity(struct cxl_region *region,
>                                             struct parsed_params *p)
>  {
>         const char *devname = cxl_region_get_devname(region);
> -       unsigned int granularity, ways;
> +       unsigned int granularity;
> +       int ways;
>  
>         /* Default granularity will be the root decoder's granularity
> */
>         granularity = cxl_decoder_get_interleave_granularity(p-
> >root_decoder);
> @@ -408,7 +406,7 @@ static int
> cxl_region_determine_granularity(struct cxl_region *region,
>                 return granularity;
>  
>         ways = cxl_decoder_get_interleave_ways(p->root_decoder);
> -       if (ways == 0 || ways == UINT_MAX) {
> +       if (ways == 0 || ways == -1) {
>                 log_err(&rl, "%s: unable to determine root decoder
> ways\n",
>                         devname);
>                 return -ENXIO;
> @@ -436,12 +434,11 @@ static int create_region(struct cxl_ctx *ctx,
> int *count,
>  {
>         unsigned long flags = UTIL_JSON_TARGETS;
>         struct json_object *jregion;
> -       unsigned int i, granularity;
>         struct cxl_region *region;
> +       int i, rc, granularity;
>         u64 size, max_extent;
>         const char *devname;
>         uuid_t uuid;
> -       int rc;
>  
>         rc = create_region_validate_config(ctx, p);
>         if (rc)
>