Re: [PATCH] iio: accel: kionix-kx022a: Apply approximate iwyu principles to includes

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Mon, 30 Jun 2025 13:42:00 +0300
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:

> On Sun, Jun 29, 2025 at 07:43:36PM +0100, Jonathan Cameron wrote:
> > On Sun, 29 Jun 2025 19:36:49 +0100
> > Jonathan Cameron <jic23@kernel.org> wrote:
> >   
> > > From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > > 
> > > Motivated by the W=1 warning about export.h that was introduced this cycle
> > > this is an attempt to apply an approximation of the principles of including
> > > whatever is used in the file directly.
> > > 
> > > Helped by the include-what-you-use tool.
> > > 
> > > Reasoning:
> > > - Drop linux/moduleparam.h as completely unused.
> > > - linux/array_size.h for ARRAY_SIZE()
> > > - linux/bitmap.h for for_each_set_bit
> > > - linux/errno.h for error codes.
> > > - linux/export.h for EXPORT_SYMBOL*()
> > > - linux/math64.h for do_div - alternative would be asm/div64.h
> > > - linux/minmax.h for min()
> > > - linux/sysfs.h for sysfs_emit()
> > > - linux/time64.h for USEC_PER_MSEC
> > > - linux/iio/buffer.h for iio_push_to_buffers_with_timestamp()
> > > - asm/byteorder.h for le16_to_cpu()
> > > 
> > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > > ---
> > > 
> > > I picked this one fairly randomly as an example but longer term I'd like
> > > to look through at least all new drivers with this in mind + all the ones
> > > that are currently messing up my W=1 build logs.
> > > 
> > > Note I've been very descriptive in this patch to allow people to suggest
> > > better alternatives for some of the ones that aren't entirely obvious.
> > >   
> > Helpfully I had a script lying around from 2021:
> > https://lore.kernel.org/all/20211003153306.391766-1-jic23@kernel.org/
> > 
> > Just for reference I used iwyu with: 
> > 
> > make LLVM=1 LOCALVERSION= W=1 -j12 C=1 CHECK=include-what-you-use CHECKFLAGS="-Xiwyu --no_default_mappings -Xiwyu --mapping_file=iio.imp"
> > 
> > where iio.imp is from a few years ago and contains:
> > 	{ include: ["\"linux/sizes.h\"", "private", <linux/sizes.h>, "public"] },
> > 	{ include: ["\"linux/slab.h\"", "private", <linux/slab.h>, "public"] },
> > 	{ include: ["\"linux/spinlock.h\"", "private", <linux/spinlock.h>, "public"] },
> > 	{ include: ["\"linux/spinlock_types.h\"", "private", <linux/spinlock.h>, "public"] },
> > 	{ include: ["\"linux/spi/spi.h\"", "private", <linux/spi/spi.h>, "public"] },
> > 	{ include: ["\"linux/stat.h\"", "private", <linux/stat.h>, "public"] },
> > 	{ include: ["\"linux/stdarg.h\"", "private", <linux/stdarg.h>, "public"] },
> > 	{ include: ["\"linux/stddef.h\"", "private", <linux/stddef.h>, "public"] },
> > 	{ include: ["\"linux/string.h\"", "private", <linux/string.h>, "public"] },
> > 	{ include: ["\"linux/stringify.h\"", "private", <linux/stringify.h>, "public"] },
> > 	{ include: ["\"linux/sysfs.h\"", "private", <linux/sysfs.h>, "public"] },
> > 	{ include: ["\"linux/types.h\"", "private", <linux/types.h>, "public"] },
> > 	{ include: ["\"linux/uuid.h\"", "private", <linux/uuid.h>, "public"] },
> > 	{ include: ["\"linux/sched.h\"", "private", <linux/sched.h>, "public"] },
> > 	{ include: ["\"linux/wait.h\"", "private", <linux/wait.h>, "public"] },
> > 	{ include: ["\"linux/workqueue.h\"", "private", <linux/workqueue.h>, "public"] },
> > 	{ include: ["\"asm-generic/int-ll64.h\"", "private", <linux/types.h>, "public"] },	
> > 	{ include: ["\"linux/device.h\"", "private", <linux/device.h>, "public"] },
> > 	{ include: ["\"linux/dev_printk.h\"", "private", <linux/device.h>, "public"] },
> > 	{ include: ["\"linux/device/bus.h\"", "private", <linux/device.h>, "public"] },
> > 	{ include: ["\"linux/device/driver.h\"", "private", <linux/device.h>, "public"] },
> > 	{ include: ["\"linux/bits.h\"", "private", <linux/bits.h>, "public"] },	
> > 	{ include: ["\"vdso/bits.h\"", "private", <linux/bits.h>, "public"] },
> > 	{ include: ["\"vdso/limits.h\"", "private", <linux/limits.h>, "public"] },
> > 	{ include: ["\"linux/limits.h\"", "private", <linux/limits.h>, "public"] },
> > 	{ include: ["\"vdso/ktime.h\"", "private", <linux/ktime.h>, "public"] },
> > 	{ include: ["\"linux/ktime.h\"", "private", <linux/ktime.h>, "public"] },
> > 	{ include: ["\"vdso/time64.h\"", "private", <linux/time64.h>, "public"] },
> > 	{ include: ["\"linux/time.h\"", "private", <linux/time.h>, "public"] },
> > 	{ include: ["\"linux/timer.h\"", "private", <linux/timer.h>, "public"] }
> > ]
> > 
> > Clear this needs a few upates, like mutex_types.h -> mutex.h and
> > probably devres.h->device.h  
> 
> Right, we got a lot of new *_types.h headers.
> This is a database (kind of) I was talking about in previous reply.
> Can we actually start it as .iwyu or so in the kernel source tree?

Nick and Tanzir talked about using iwyu at Plumbers 2023 and probably have
a much better starting point that this (even more) ancient version.
I missed the talk completely at the time, but came across it more recently.

+CC them both

Jonathan