Patch "zram: do not mark idle slots that cannot be idle" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    zram: do not mark idle slots that cannot be idle

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     zram-do-not-mark-idle-slots-that-cannot-be-idle.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 130f4c81955837169f55c2fb03ee5bf84c03a2b2
Author: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Date:   Tue Sep 17 11:09:10 2024 +0900

    zram: do not mark idle slots that cannot be idle
    
    [ Upstream commit b967fa1ba72b5da2b6d9bf95f0b13420a59e0701 ]
    
    ZRAM_SAME slots cannot be post-processed (writeback or recompress) so do
    not mark them ZRAM_IDLE.  Same with ZRAM_WB slots, they cannot be
    ZRAM_IDLE because they are not in zsmalloc pool anymore.
    
    Link: https://lkml.kernel.org/r/20240917021020.883356-6-senozhatsky@xxxxxxxxxxxx
    Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
    Cc: Minchan Kim <minchan@xxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
    Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 582df13bfde94..e05eace18cc47 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -297,17 +297,28 @@ static void mark_idle(struct zram *zram, ktime_t cutoff)
 		/*
 		 * Do not mark ZRAM_UNDER_WB slot as ZRAM_IDLE to close race.
 		 * See the comment in writeback_store.
+		 *
+		 * Also do not mark ZRAM_SAME slots as ZRAM_IDLE, because no
+		 * post-processing (recompress, writeback) happens to the
+		 * ZRAM_SAME slot.
+		 *
+		 * And ZRAM_WB slots simply cannot be ZRAM_IDLE.
 		 */
 		zram_slot_lock(zram, index);
-		if (zram_allocated(zram, index) &&
-				!zram_test_flag(zram, index, ZRAM_UNDER_WB)) {
+		if (!zram_allocated(zram, index) ||
+		    zram_test_flag(zram, index, ZRAM_WB) ||
+		    zram_test_flag(zram, index, ZRAM_UNDER_WB) ||
+		    zram_test_flag(zram, index, ZRAM_SAME)) {
+			zram_slot_unlock(zram, index);
+			continue;
+		}
+
 #ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
-			is_idle = !cutoff || ktime_after(cutoff,
-							 zram->table[index].ac_time);
+		is_idle = !cutoff ||
+			ktime_after(cutoff, zram->table[index].ac_time);
 #endif
-			if (is_idle)
-				zram_set_flag(zram, index, ZRAM_IDLE);
-		}
+		if (is_idle)
+			zram_set_flag(zram, index, ZRAM_IDLE);
 		zram_slot_unlock(zram, index);
 	}
 }