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From:   Xin Hao <xhao@linux.alibaba.com>
To:     sj@kernel.org
Cc:     akpm@linux-foundation.org, damon@lists.linux.dev,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        xhao@linux.alibaba.com
Subject: [PATCH] mm/damon/lru_sort: Move target memory region check to head of func
Date:   Thu, 18 Aug 2022 16:25:38 +0800
Message-Id: <20220818082538.67825-1-xhao@linux.alibaba.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In damon_lru_sort_apply_parameters(), if "monitor_region_start"
and "monitor_region_end" is not a valid physical address range,
There no need to run the remainder codes in it.

Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
---
 mm/damon/lru_sort.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c
index 9de6f00a71c5..ac50dca026f9 100644
--- a/mm/damon/lru_sort.c
+++ b/mm/damon/lru_sort.c
@@ -378,6 +378,13 @@ static int damon_lru_sort_apply_parameters(void)
 	unsigned int hot_thres, cold_thres;
 	int err = 0;

+	if (monitor_region_start > monitor_region_end)
+		return -EINVAL;
+	if (!monitor_region_start && !monitor_region_end &&
+			!get_monitoring_region(&monitor_region_start,
+				&monitor_region_end))
+		return -EINVAL;
+
 	err = damon_set_attrs(ctx, sample_interval, aggr_interval, 0,
 			min_nr_regions, max_nr_regions);
 	if (err)
@@ -401,12 +408,6 @@ static int damon_lru_sort_apply_parameters(void)
 		return -ENOMEM;
 	damon_add_scheme(ctx, scheme);

-	if (monitor_region_start > monitor_region_end)
-		return -EINVAL;
-	if (!monitor_region_start && !monitor_region_end &&
-			!get_monitoring_region(&monitor_region_start,
-				&monitor_region_end))
-		return -EINVAL;
 	addr_range.start = monitor_region_start;
 	addr_range.end = monitor_region_end;
 	return damon_set_regions(target, &addr_range, 1);
--
2.31.0