On Mon, Mar 19, 2018 at 04:45:30PM -0700, Dave Jiang wrote:
> Adding helper functions to iterate through sysfs region persistence domain
> attribute. The region will display the domain with the most persistence for
> the
> region. The bus will display the domain attribute with the least persistence
> amongst all the regions. ndctl_bus_get_persistence_domain() and
> ndctl_region_get_persistence_domain are exported. ndctl list will also display
> the region persistence domain as well.
>
> Signed-off-by: Dave Jiang <[email protected]>
Nice this is cleaner, and you've shaved off 20 lines. :)
> @@ -755,6 +756,7 @@ static void *add_bus(void *parent, int id, const char
> *ctl_base)
> list_head_init(&bus->regions);
> bus->ctx = ctx;
> bus->id = id;
> + bus->persistence_domain = PERSISTENCE_UNKNOWN;
>
> sprintf(path, "%s/dev", ctl_base);
> if (sysfs_read_attr(ctx, path, buf) < 0
> @@ -916,6 +918,17 @@ NDCTL_EXPORT struct ndctl_bus
> *ndctl_bus_get_by_provider(struct ndctl_ctx *ctx,
> return NULL;
> }
>
> +NDCTL_EXPORT unsigned int
Can we make this return an enum ndctl_persistence, like the internal functions
do? This follows the lead of APIs like ndctl_namespace_get_mode(), which by
returning an enum ndctl_namespace_mode tells the user what values to expect
and what those values mean.
Ditto for the ndctl_region_get_persistence_domain(), and the two external
declarations in libndctl.h.
> +ndctl_bus_get_persistence_domain(struct ndctl_bus *bus)
> +{
> + struct ndctl_region *region;
> +
> + /* iterate through region to get the region persistence domain */
> + ndctl_region_foreach(bus, region) {}
I still don't understand why you need to do a ndctl_region_foreach() here,
looping through all the regions on a bus? I think you're just after the
initialization that
ndctl_region_foreach()
ndctl_region_get_first()
regions_init()
gives you, right? If so, let's be more clear about that and just call
regions_init() directly. This also saves the work of needlessly looping
through the regions, and makes it so you don't need a local 'region' variable.
> +
> + return bus->persistence_domain;
> +}
> +
> NDCTL_EXPORT struct ndctl_btt *ndctl_region_get_btt_seed(struct ndctl_region
> *region)
> {
> struct ndctl_ctx *ctx = ndctl_region_get_ctx(region);
> @@ -1755,6 +1768,62 @@ static int region_set_type(struct ndctl_region
> *region, char *path)
> return 0;
> }
>
> +static enum ndctl_persistence region_get_pd_type(char *name)
> +{
> + if (strncmp("cpu_cache", name, 9) == 0)
> + return PERSISTENCE_CPU_CACHE;
> + else if (strncmp("memory_controller", name, 17) == 0)
> + return PERSISTENCE_MEM_CTRL;
> + else
> + return PERSISTENCE_UNKNOWN;
> +}
> +
> +static int region_persistence_scan(struct ndctl_region *region)
> +{
> + struct ndctl_ctx *ctx = ndctl_region_get_ctx(region);
> + char *pd_path;
> + FILE *pf;
> + char buf[64];
> + int rc = 0;
> + enum ndctl_persistence pd = PERSISTENCE_NONE;
> +
> + if (asprintf(&pd_path, "%s/persistence_domain",
> + region->region_path) < 0) {
> + rc = -errno;
> + err(ctx, "region persist domain path allocation failure\n");
> + return rc;
> + }
> +
> + pf = fopen(pd_path, "re");
> + if (!pf) {
> + rc = -errno;
> + free(pd_path);
> + return rc;
> + }
> +
> + region->persistence_domain = PERSISTENCE_NONE;
I think that this initialization needs to happen at the top of the function
before we have any return paths. This is because the code that calls this,
add_region(), doesn't set region->persistence_domain if we give an error
return. I think that this means that if the asprintf() fails, for example, we
will end up with region->persistence_domain being uninitialized.
> + do {
> + rc = fscanf(pf, "%s", buf);
> + if (rc == EOF) {
> + if (ferror(pf)) {
> + rc = -errno;
> + goto out;
> + }
> + } else if (rc == 1)
> + pd = region_get_pd_type(buf);
> +
> + if (region->persistence_domain < pd)
> + region->persistence_domain = pd;
> + } while (rc != EOF);
> +
> + rc = 0;
> +
> +out:
> + fclose(pf);
> + free(pd_path);
> + return rc;
> +}
> +
> static void *add_region(void *parent, int id, const char *region_base)
> {
> char buf[SYSFS_ATTR_SIZE];
> @@ -1762,6 +1831,7 @@ static void *add_region(void *parent, int id, const
> char *region_base)
> struct ndctl_bus *bus = parent;
> struct ndctl_ctx *ctx = bus->ctx;
> char *path = calloc(1, strlen(region_base) + 100);
> + int rc;
>
> if (!path)
> return NULL;
> @@ -1831,6 +1901,17 @@ static void *add_region(void *parent, int id, const
> char *region_base)
> list_add(&bus->regions, ®ion->list);
>
> free(path);
> +
> + /* get the persistence domain attribs */
> + rc = region_persistence_scan(region);
> + if (rc < 0)
> + err(ctx, "%s: region persistence scan failed\n",
> + ndctl_region_get_devname(region));
Nit: no need for 'rc' here, just follow the lead of the rest of the if()
statements in this function and do
if (region_persistence_scan(region) < 0) {
err(...
}
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