# \[PATCH\] hypverv/vmbus: include linux/bitops.h

- From: Arnd Bergmann \<arnd@kernel.org\>
- Date: 2021-10-18 13:19:43 
- List: linux-hyperv
- Page: https://ratatoskr.run/linux-hyperv/2021/10/1545419
- Thread: https://ratatoskr.run/linux-hyperv/2021/10/1545419/t.md

```text
From: Arnd Bergmann <arnd@arndb.de>

On arm64 randconfig builds, hyperv sometimes fails with this
error:

In file included from drivers/hv/hv_trace.c:3:
In file included from drivers/hv/hyperv_vmbus.h:16:
In file included from arch/arm64/include/asm/sync_bitops.h:5:
arch/arm64/include/asm/bitops.h:11:2: error: only <linux/bitops.h> can be included directly
In file included from include/asm-generic/bitops/hweight.h:5:
include/asm-generic/bitops/arch_hweight.h:9:9: error: implicit declaration of function '__sw_hweight32' [-Werror,-Wimplicit-function-declaration]
include/asm-generic/bitops/atomic.h:17:7: error: implicit declaration of function 'BIT_WORD' [-Werror,-Wimplicit-function-declaration]

Include the correct header first.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
Not sure what started this, I first saw it on linux-next-20211015
---
 drivers/hv/hyperv_vmbus.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 42f3d9d123a1..d030577ad6a2 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -13,6 +13,7 @@
 #define _HYPERV_VMBUS_H
 
 #include <linux/list.h>
+#include <linux/bitops.h>
 #include <asm/sync_bitops.h>
 #include <asm/hyperv-tlfs.h>
 #include <linux/atomic.h>
-- 
2.29.2

```