Re: [ndctl PATCH 3/8] libndctl: add APIs to get scrub count and to wait for a scrub

The kernel uses sysfs to notify userspace of the number of completed Address Range Scrubs, as well as any ongoing scrubs. Add libndctl helpers to get the scrub count, and to wait for an in-progress scrub to complete. Cc: Dan Williams <dan.j.williams(a)intel.com&gt; Signed-off-by: Vishal Verma <vishal.l.verma(a)intel.com&gt; --- ndctl/lib/libndctl.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++ ndctl/lib/libndctl.sym | 2 ++ ndctl/lib/private.h | 1 + ndctl/libndctl.h.in | 2 ++ 4 files changed, 90 insertions(+) diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c index 60143d9..3943978 100644 --- a/ndctl/lib/libndctl.c +++ b/ndctl/lib/libndctl.c @@ -555,6 +555,7 @@ static void free_bus(struct ndctl_bus *bus, struct list_head *head) free(bus->bus_path); free(bus->bus_buf); free(bus->wait_probe_path); + free(bus->scrub_path); free(bus); } @@ -785,6 +786,11 @@ static void *add_bus(void *parent, int id, const char *ctl_base) if (!bus->wait_probe_path) goto err_read; + sprintf(path, "%s/device/nfit/scrub", ctl_base); + bus->scrub_path = strdup(path); + if (!bus->scrub_path) + goto err_read; + bus->bus_path = parent_dev_path("char", bus->major, bus->minor); if (!bus->bus_path) goto err_dev_path; @@ -810,6 +816,7 @@ static void *add_bus(void *parent, int id, const char *ctl_base) err_dev_path: err_read: free(bus->wait_probe_path); + free(bus->scrub_path); free(bus->provider); free(bus->bus_buf); free(bus); @@ -1082,6 +1089,84 @@ NDCTL_EXPORT int ndctl_bus_wait_probe(struct ndctl_bus *bus) return rc < 0 ? -ENXIO : 0; } +NDCTL_EXPORT unsigned int ndctl_bus_get_scrub_count(struct ndctl_bus *bus) +{ + struct ndctl_ctx *ctx = ndctl_bus_get_ctx(bus); + char buf[SYSFS_ATTR_SIZE]; + unsigned int scrub_count; + char in_progress = '\0'; + int rc; + + rc = sysfs_read_attr(ctx, bus->scrub_path, buf); + if (rc < 0) + return UINT_MAX; + + rc = sscanf(buf, "%u%c", &scrub_count, &in_progress); + if (rc < 0) + return UINT_MAX; + if (rc == 0) { + /* unable to read scrub count */ + return UINT_MAX; + } + if (rc >= 1) + return scrub_count; + + return UINT_MAX; +} + +/** + * ndctl_bus_wait_for_scrub - wait for a scrub to complete + * @bus: bus for which to check whether a scrub is in progress + * + * Upon return this bus has completed any in-progress scrubs. This is + * different from ndctl_cmd_ars_in_progress in that the latter checks + * the output of an ars_status command to see if the in-progress flag + * is set, i.e. provides the firmware's view of whether a scrub is in + * progress. ndctl_bus_wait_for_scrub instead checks the kernel's view + * of whether a scrub is in progress by looking at the 'scrub' file in + * sysfs. + */ +NDCTL_EXPORT int ndctl_bus_wait_for_scrub_completion(struct ndctl_bus *bus) +{ + struct ndctl_ctx *ctx = ndctl_bus_get_ctx(bus); + unsigned int tmo = 120, scrub_count; + char buf[SYSFS_ATTR_SIZE]; + char in_progress = '\0'; + int rc, elapsed = 0; + + do { + rc = sysfs_read_attr(ctx, bus->scrub_path, buf); + if (rc < 0) + break; + + rc = sscanf(buf, "%u%c", &scrub_count, &in_progress); + if (rc < 0) + break; + else if (rc <= 1) { + /* scrub complete, break successfully */ + rc = 0; + break; + } else if (rc == 2 && in_progress == '+') { + /* scrub in progress, continue to wait */ + ; + } else { + /* unknown condition */ + rc = -ENXIO; + break; + } + + elapsed++; + sleep(1); + } while (tmo-- != 0);