From: Nathan Chancellor natechancellor@gmail.com
[ Upstream commit afb34781620274236bd9fc9246e22f6963ef5262 ]
When building with Clang + -Wtautological-constant-compare, several of the ivtv and cx18 drivers warn along the lines of:
drivers/media/pci/cx18/cx18-driver.c:1005:21: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare] cx18_call_hw(cx, CX18_HW_GPIO_RESET_CTRL, ^ drivers/media/pci/cx18/cx18-cards.h:18:37: note: expanded from macro 'CX18_HW_GPIO_RESET_CTRL' #define CX18_HW_GPIO_RESET_CTRL (1 << 6) ^ 1 warning generated.
This warning happens because the shift operation is implicitly converted to a boolean in v4l2_device_mask_call_all before being negated. This can be solved by just comparing the mask result to 0 explicitly so that there is no boolean conversion. The ultimate goal is to enable -Wtautological-compare globally because there are several subwarnings that would be helpful to have.
For visual consistency and avoidance of these warnings in the future, all of the implicitly boolean conversions in the v4l2_device macros are converted to explicit ones as well.
Link: https://github.com/ClangBuiltLinux/linux/issues/752
Reviewed-by: Ezequiel Garcia ezequiel@collabora.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab+huawei@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/media/v4l2-device.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h index e0b8f2602670d..a0e93f0ef62a1 100644 --- a/include/media/v4l2-device.h +++ b/include/media/v4l2-device.h @@ -371,7 +371,7 @@ static inline bool v4l2_device_supports_requests(struct v4l2_device *v4l2_dev) struct v4l2_subdev *__sd; \ \ __v4l2_device_call_subdevs_p(v4l2_dev, __sd, \ - !(grpid) || __sd->grp_id == (grpid), o, f , \ + (grpid) == 0 || __sd->grp_id == (grpid), o, f , \ ##args); \ } while (0)
@@ -403,7 +403,7 @@ static inline bool v4l2_device_supports_requests(struct v4l2_device *v4l2_dev) ({ \ struct v4l2_subdev *__sd; \ __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, \ - !(grpid) || __sd->grp_id == (grpid), o, f , \ + (grpid) == 0 || __sd->grp_id == (grpid), o, f , \ ##args); \ })
@@ -431,8 +431,8 @@ static inline bool v4l2_device_supports_requests(struct v4l2_device *v4l2_dev) struct v4l2_subdev *__sd; \ \ __v4l2_device_call_subdevs_p(v4l2_dev, __sd, \ - !(grpmsk) || (__sd->grp_id & (grpmsk)), o, f , \ - ##args); \ + (grpmsk) == 0 || (__sd->grp_id & (grpmsk)), o, \ + f , ##args); \ } while (0)
/** @@ -462,8 +462,8 @@ static inline bool v4l2_device_supports_requests(struct v4l2_device *v4l2_dev) ({ \ struct v4l2_subdev *__sd; \ __v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, \ - !(grpmsk) || (__sd->grp_id & (grpmsk)), o, f , \ - ##args); \ + (grpmsk) == 0 || (__sd->grp_id & (grpmsk)), o, \ + f , ##args); \ })