drivers/base/memory: simplify outputting of valid_zones_show()

No need to specify position at the first writing to the buf because the
@len is always 0 at this time.  Use sysfs_emit() instead to simplify it.
Also avoid setting/checking default_zone with a conditional operator.

Link: https://lkml.kernel.org/r/20250108015223.1522887-1-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 348c5db..4765f29 100644 (file)
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -455,7 +455,7 @@ static ssize_t valid_zones_show(struct device *dev,
        struct memory_group *group = mem->group;
        struct zone *default_zone;
        int nid = mem->nid;
-       int len = 0;
+       int len;
 
        /*
         * Check the existing zone. Make sure that we do that only on the
@@ -466,22 +466,18 @@ static ssize_t valid_zones_show(struct device *dev,
                 * If !mem->zone, the memory block spans multiple zones and
                 * cannot get offlined.
                 */
-               default_zone = mem->zone;
-               if (!default_zone)
-                       return sysfs_emit(buf, "%s\n", "none");
-               len += sysfs_emit_at(buf, len, "%s", default_zone->name);
-               goto out;
+               return sysfs_emit(buf, "%s\n",
+                                 mem->zone ? mem->zone->name : "none");
        }
 
        default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, group,
                                          start_pfn, nr_pages);
 
-       len += sysfs_emit_at(buf, len, "%s", default_zone->name);
+       len = sysfs_emit(buf, "%s", default_zone->name);
        len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,
                                  MMOP_ONLINE_KERNEL, default_zone);
        len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,
                                  MMOP_ONLINE_MOVABLE, default_zone);
-out:
        len += sysfs_emit_at(buf, len, "\n");
        return len;
 }