When building with clang, there is a warning (or error with CONFIG_WERROR=y) due to a bitwise AND and logical NOT in vfio_cdx_bm_ctrl(): drivers/vfio/cdx/main.c:77:6: error: logical not is only applied to the left hand side of this bitwise operator [-Werror,-Wlogical-not-parentheses] 77 | if (!vdev->flags & BME_SUPPORT) | ^ ~ drivers/vfio/cdx/main.c:77:6: note: add parentheses after the '!' to evaluate the bitwise operator first 77 | if (!vdev->flags & BME_SUPPORT) | ^ | ( ) drivers/vfio/cdx/main.c:77:6: note: add parentheses around left hand side expression to silence this warning 77 | if (!vdev->flags & BME_SUPPORT) | ^ | ( ) 1 error generated. Add the parentheses as suggested in the first note, which is clearly what was intended here. Closes: https://github.com/ClangBuiltLinux/linux/issues/1939 Fixes: 8a97ab9b8b31 ("vfio-cdx: add bus mastering device feature support") Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> --- drivers/vfio/cdx/main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vfio/cdx/main.c b/drivers/vfio/cdx/main.c index a437630be354..a63744302b5e 100644 --- a/drivers/vfio/cdx/main.c +++ b/drivers/vfio/cdx/main.c @@ -74,7 +74,7 @@ static int vfio_cdx_bm_ctrl(struct vfio_device *core_vdev, u32 flags, struct vfio_device_feature_bus_master ops; int ret; - if (!vdev->flags & BME_SUPPORT) + if (!(vdev->flags & BME_SUPPORT)) return -ENOTTY; ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, --- base-commit: fcb2f2ed4a80cfe383d87da75caba958516507e9 change-id: 20231002-vfio-cdx-logical-not-parentheses-aca8fbd6b278 Best regards, -- Nathan Chancellor <nathan@xxxxxxxxxx>