linux-kernel - [PATCHv2 2/2] zram: clear IDLE flag in mark

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Message-ID: <20241028153629.1479791-3-senozhatsky@chromium.org>
Date: Tue, 29 Oct 2024 00:36:15 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Minchan Kim <minchan@...nel.org>,
	linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCHv2 2/2] zram: clear IDLE flag in mark_idle()

If entry does not fulfill current mark_idle() parameters, e.g.
cutoff time, then we should clear its ZRAM_IDLE from previous
mark_idle() invocations.

Consider the following case:
- mark_idle() cutoff time 8h
- mark_idle() cutoff time 4h
- writeback() idle - will writeback entries with cutoff time 8h,
  while it should only pick entries with cutoff time 4h

The bug was reported by Shin Kawamura.

Fixes: 755804d16965 ("zram: introduce an aged idle interface")
Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
 drivers/block/zram/zram_drv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index a16dbffcdca3..cee49bb0126d 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -410,6 +410,8 @@ static void mark_idle(struct zram *zram, ktime_t cutoff)
 #endif
 		if (is_idle)
 			zram_set_flag(zram, index, ZRAM_IDLE);
+		else
+			zram_clear_flag(zram, index, ZRAM_IDLE);
 		zram_slot_unlock(zram, index);
 	}
 }
-- 
2.47.0.163.g1226f6d8fa-goog