mm/damon/core: simplify the kdamond stop mechanism by removing 'done'

When the 'kdamond_wait_activation()' function or 'after_sampling()' or
'after_aggregation()' DAMON callbacks return an error, it is unnecessary
to use bool 'done' to check if kdamond should be finished.  This commit
simplifies the kdamond stop mechanism by removing 'done' and break the
while loop directly in the cases.

Link: https://lkml.kernel.org/r/1663060287-30201-4-git-send-email-kaixuxia@tencent.comSigned-off-by: NKaixu Xia <kaixuxia@tencent.com>
Reviewed-by: NSeongJae Park <sj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

mm/damon/core.c

@@ -1152,30 +1152,25 @@ static int kdamond_fn(void *data)
 	struct damon_region *r, *next;
 	unsigned int max_nr_accesses = 0;
 	unsigned long sz_limit = 0;
-	bool done = false;
 
 	pr_debug("kdamond (%d) starts\n", current->pid);
 
 	if (ctx->ops.init)
 		ctx->ops.init(ctx);
 	if (ctx->callback.before_start && ctx->callback.before_start(ctx))
-		done = true;
+		goto done;
 
 	sz_limit = damon_region_sz_limit(ctx);
 
-	while (!kdamond_need_stop(ctx) && !done) {
-		if (kdamond_wait_activation(ctx)) {
-			done = true;
-			continue;
-		}
+	while (!kdamond_need_stop(ctx)) {
+		if (kdamond_wait_activation(ctx))
+			break;
 
 		if (ctx->ops.prepare_access_checks)
 			ctx->ops.prepare_access_checks(ctx);
 		if (ctx->callback.after_sampling &&
-				ctx->callback.after_sampling(ctx)) {
-			done = true;
-			continue;
-		}
+				ctx->callback.after_sampling(ctx))
+			break;
 
 		kdamond_usleep(ctx->attrs.sample_interval);
 
@@ -1187,10 +1182,8 @@ static int kdamond_fn(void *data)
 					max_nr_accesses / 10,
 					sz_limit);
 			if (ctx->callback.after_aggregation &&
-					ctx->callback.after_aggregation(ctx)) {
-				done = true;
-				continue;
-			}
+					ctx->callback.after_aggregation(ctx))
+				break;
 			kdamond_apply_schemes(ctx);
 			kdamond_reset_aggregated(ctx);
 			kdamond_split_regions(ctx);
@@ -1204,6 +1197,7 @@ static int kdamond_fn(void *data)
 			sz_limit = damon_region_sz_limit(ctx);
 		}
 	}
+done:
 	damon_for_each_target(t, ctx) {
 		damon_for_each_region_safe(r, next, t)
 			damon_destroy_region(r, t);