mm/damon/core: finish kdamond as soon as any callback returns an error

When 'after_sampling()' or 'after_aggregation()' DAMON callbacks return an
error, kdamond continues the remaining loop once.  It makes no much sense
to run the remaining part while something wrong already happened.  The
context might be corrupted or having invalid data.  This commit therefore
makes kdamond skips the remaining works and immediately finish in the
cases.

Link: https://lkml.kernel.org/r/20220429160606.127307-3-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core.c

@@ -1089,8 +1089,10 @@ static int kdamond_fn(void *data)
 		if (ctx->ops.prepare_access_checks)
 			ctx->ops.prepare_access_checks(ctx);
 		if (ctx->callback.after_sampling &&
-				ctx->callback.after_sampling(ctx))
+				ctx->callback.after_sampling(ctx)) {
 			done = true;
+			continue;
+		}
 
 		kdamond_usleep(ctx->sample_interval);
 
@@ -1102,8 +1104,10 @@ static int kdamond_fn(void *data)
 					max_nr_accesses / 10,
 					sz_limit);
 			if (ctx->callback.after_aggregation &&
-					ctx->callback.after_aggregation(ctx))
+					ctx->callback.after_aggregation(ctx)) {
 				done = true;
+				continue;
+			}
 			kdamond_apply_schemes(ctx);
 			kdamond_reset_aggregated(ctx);
 			kdamond_split_regions(ctx);