zram: only make zram_wb_devops for CONFIG_ZRAM_WRITEBACK

If writeback isn't configured, then we get the following warning when
compiling zram:

drivers/block/zram/zram_drv.c:1824:45: warning: unused variable 'zram_wb_devops' [-Wunused-const-variable]

Make sure we only define the block_device_operations if that option is
enabled.

Link: https://lore.kernel.org/lkml/202111261614.gCJMqcyh-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 08d7953ec5f107483b217d382484980691884d92..25071126995befb16c69e2c88a590fb54dd0491b 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1853,12 +1853,14 @@ static const struct block_device_operations zram_devops = {
        .owner = THIS_MODULE
 };
 
+#ifdef CONFIG_ZRAM_WRITEBACK
 static const struct block_device_operations zram_wb_devops = {
        .open = zram_open,
        .submit_bio = zram_submit_bio,
        .swap_slot_free_notify = zram_slot_free_notify,
        .owner = THIS_MODULE
 };
+#endif
 
 static DEVICE_ATTR_WO(compact);
 static DEVICE_ATTR_RW(disksize);