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@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index d6a1ba969266a4bb9fbef83119f8edf8c89526ae..d7f7cc31aaa69c97cab1c40e90e1e69f99ce3d3c 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -298,17 +298,28 @@ 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);
        }
 }