On (25/02/03 16:11), Sergey Senozhatsky wrote:
> I guess where we actually need zram entry lock is writeback and
> recompression. Writeback moves object from zsmalloc pool to actual
> physical storage, freeing zsmalloc memory after that and setting
> zram entry[index] handle to the backikng device's block idx, which
> needs synchronization. Recompression does a similar thing, it frees
> the old zsmalloc handle and stores recompressed objects under new
> zsmalloc handle, it thus updates zram entry[index] handle to point
> to the new location, which needs to be synchronized.
... Luckily there is a trivial solution
---
diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
index 402b7b175863..dd7c5ae91cc0 100644
--- a/drivers/block/zram/Kconfig
+++ b/drivers/block/zram/Kconfig
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
config ZRAM
tristate "Compressed RAM block device support"
- depends on BLOCK && SYSFS && MMU
+ depends on BLOCK && SYSFS && MMU && !PREEMPT
select ZSMALLOC
help
Creates virtual block devices called /dev/zramX (X = 0, 1, ...).
