Em Fri, 26 Nov 2021 12:58:33 -0700 Nathan Chancellor <nathan@xxxxxxxxxx> escreveu: > On Wed, Nov 24, 2021 at 08:13:11PM +0100, Mauro Carvalho Chehab wrote: > > There are several unused helper macros there, meant to parse some > > fields. > > > > While there's not wrong with that, it generates clang warnings > > with W=1, causing build to break with CONFIG_WERROR. > > > > So, add __maybe_unused to fix such warnings. > > > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> > > I'll comment on this one patch but my opinion applies for all the > patches adding '__maybe_unused' to truly unused functions. > > I agree with Laurent's comment [1]: unless this code is going to be used > soon, it should be deleted and resurrected when it is actually needed. > We have git for a reason and by adding this attribute, you are making it > harder to catch and eliminate unused functions, as no compiler will > catch them with an unused attribute (it is possible other static > analysis tools will but I doubt those are run as frequently as compilers > with W=1). In this specific case (and on a few other patches on this series), those macros are used to document a field. That's why I opted to keep it. > > However, you are the maintainer so if you really want to keep these > around, I would recommend adding '__always_unused' instead of > '__maybe_unused' for documentation and auditing purposes, even though > they evaluate to the same thing: > > $ rg __always_unused | wc -l > 337 > > $ rg __maybe_unused | wc -l > 4335 Good point. I'll use __always_unused on such patches. > > [1]: https://lore.kernel.org/r/YZtpnjPcGxVwhe61@xxxxxxxxxxxxxxxxxxxxxxxxxx/ > > Cheers, > Nathan > > > --- > > > > To avoid mailbombing on a large number of people, only mailing lists were C/C on the cover. > > See [PATCH 00/20] at: https://lore.kernel.org/all/cover.1637781097.git.mchehab+huawei@xxxxxxxxxx/ > > > > drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c | 12 ++++++------ > > 1 file changed, 6 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c b/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c > > index 0abcad4e84fa..85eaf5d00e9b 100644 > > --- a/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c > > +++ b/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c > > @@ -391,12 +391,12 @@ static int solo_send_desc(struct solo_enc_dev *solo_enc, int skip, > > } > > > > /* Extract values from VOP header - VE_STATUSxx */ > > -static inline int vop_interlaced(const vop_header *vh) > > +static inline __maybe_unused int vop_interlaced(const vop_header *vh) > > { > > return (__le32_to_cpu((*vh)[0]) >> 30) & 1; > > } > > > > -static inline u8 vop_channel(const vop_header *vh) > > +static inline __maybe_unused u8 vop_channel(const vop_header *vh) > > { > > return (__le32_to_cpu((*vh)[0]) >> 24) & 0x1F; > > } > > @@ -411,12 +411,12 @@ static inline u32 vop_mpeg_size(const vop_header *vh) > > return __le32_to_cpu((*vh)[0]) & 0xFFFFF; > > } > > > > -static inline u8 vop_hsize(const vop_header *vh) > > +static inline u8 __maybe_unused vop_hsize(const vop_header *vh) > > { > > return (__le32_to_cpu((*vh)[1]) >> 8) & 0xFF; > > } > > > > -static inline u8 vop_vsize(const vop_header *vh) > > +static inline u8 __maybe_unused vop_vsize(const vop_header *vh) > > { > > return __le32_to_cpu((*vh)[1]) & 0xFF; > > } > > @@ -436,12 +436,12 @@ static inline u32 vop_jpeg_size(const vop_header *vh) > > return __le32_to_cpu((*vh)[4]) & 0xFFFFF; > > } > > > > -static inline u32 vop_sec(const vop_header *vh) > > +static inline u32 __maybe_unused vop_sec(const vop_header *vh) > > { > > return __le32_to_cpu((*vh)[5]); > > } > > > > -static inline u32 vop_usec(const vop_header *vh) > > +static inline __maybe_unused u32 vop_usec(const vop_header *vh) > > { > > return __le32_to_cpu((*vh)[6]); > > } > > -- > > 2.33.1 > > > > Thanks, Mauro
