[PATCH v3 0/2] Cleanup io.h

[PATCH v3 0/2] Cleanup io.h

[Raag Jadav]

This series attempts to cleanup io.h with "include what you use" approach.
This depends on changes available on immutable tag[1].

Although this series is too trivial in the grand scheme of things, it is
still a tiny step towards untangling core headers. I have success results
from LKP for this series but there can still be corner cases. So perhaps
we can queue this on a temporary branch which we can use to submit fixes
in case of fallout.

Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
headers.

[1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
[2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
[3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com

v2: Fix sparc build errors
v3: Fix nios2 build errors and re-order patches

Raag Jadav (2):
  drm/draw: include missing headers
  io.h: drop unused headers

 drivers/gpu/drm/drm_draw.c | 2 ++
 include/linux/io.h         | 3 ---
 2 files changed, 2 insertions(+), 3 deletions(-)


base-commit: b8c38ccb2ca52b9a38cfeb9f89abab5d6e713221
-- 
2.34.1

[PATCH v3 1/2] drm/draw: include missing headers

[Raag Jadav]

Include headers for the symbols directly used in this file instead of
relying on intermediate headers.

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
---
 drivers/gpu/drm/drm_draw.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/drm_draw.c b/drivers/gpu/drm/drm_draw.c
index cb2ad12bce57..385eb5e10047 100644
--- a/drivers/gpu/drm/drm_draw.c
+++ b/drivers/gpu/drm/drm_draw.c
@@ -5,6 +5,8 @@
  */
 
 #include <linux/bits.h>
+#include <linux/bug.h>
+#include <linux/export.h>
 #include <linux/iosys-map.h>
 #include <linux/types.h>
 
-- 
2.34.1

[PATCH v3 2/2] io.h: drop unused headers

[Raag Jadav]

Drop unused headers and type declaration from io.h.

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/linux/io.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/include/linux/io.h b/include/linux/io.h
index 40cb2de73f5e..6a6bc4d46d0a 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -9,13 +9,10 @@
 #include <linux/sizes.h>
 #include <linux/types.h>
 #include <linux/init.h>
-#include <linux/bug.h>
-#include <linux/err.h>
 #include <asm/io.h>
 #include <asm/page.h>
 
 struct device;
-struct resource;
 
 #ifndef __iowrite32_copy
 void __iowrite32_copy(void __iomem *to, const void *from, size_t count);
-- 
2.34.1

Re: [PATCH v3 0/2] Cleanup io.h

[Andy Shevchenko]

On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
> This series attempts to cleanup io.h with "include what you use" approach.
> This depends on changes available on immutable tag[1].
> 
> Although this series is too trivial in the grand scheme of things, it is
> still a tiny step towards untangling core headers. I have success results
> from LKP for this series but there can still be corner cases. So perhaps
> we can queue this on a temporary branch which we can use to submit fixes
> in case of fallout.
> 
> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
> headers.
> 
> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com

I believe Arnd can take it through his tree for headers as DRM part is Acked already.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 0/2] Cleanup io.h

[Arnd Bergmann]

On Thu, Feb 27, 2025, at 16:25, Andy Shevchenko wrote:
> On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
>> This series attempts to cleanup io.h with "include what you use" approach.
>> This depends on changes available on immutable tag[1].
>> 
>> Although this series is too trivial in the grand scheme of things, it is
>> still a tiny step towards untangling core headers. I have success results
>> from LKP for this series but there can still be corner cases. So perhaps
>> we can queue this on a temporary branch which we can use to submit fixes
>> in case of fallout.
>> 
>> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
>> headers.
>> 
>> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
>> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
>> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com
>
> I believe Arnd can take it through his tree for headers as DRM part is 
> Acked already.

I've applied it yesterday and not seen any regression reports so far.

    Arnd

Re: [PATCH v3 0/2] Cleanup io.h

[Raag Jadav]

On Fri, Feb 28, 2025 at 06:11:16PM +0100, Arnd Bergmann wrote:
> On Thu, Feb 27, 2025, at 16:25, Andy Shevchenko wrote:
> > On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
> >> This series attempts to cleanup io.h with "include what you use" approach.
> >> This depends on changes available on immutable tag[1].
> >> 
> >> Although this series is too trivial in the grand scheme of things, it is
> >> still a tiny step towards untangling core headers. I have success results
> >> from LKP for this series but there can still be corner cases. So perhaps
> >> we can queue this on a temporary branch which we can use to submit fixes
> >> in case of fallout.
> >> 
> >> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
> >> headers.
> >> 
> >> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
> >> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
> >> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com
> >
> > I believe Arnd can take it through his tree for headers as DRM part is 
> > Acked already.
> 
> I've applied it yesterday and not seen any regression reports so far.

Probably because the immutable tag is already in -next?

Raag

Re: [PATCH v3 0/2] Cleanup io.h

[Andy Shevchenko]

On Fri, Feb 28, 2025 at 07:41:55PM +0200, Raag Jadav wrote:
> On Fri, Feb 28, 2025 at 06:11:16PM +0100, Arnd Bergmann wrote:
> > On Thu, Feb 27, 2025, at 16:25, Andy Shevchenko wrote:
> > > On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
> > >> This series attempts to cleanup io.h with "include what you use" approach.
> > >> This depends on changes available on immutable tag[1].
> > >> 
> > >> Although this series is too trivial in the grand scheme of things, it is
> > >> still a tiny step towards untangling core headers. I have success results
> > >> from LKP for this series but there can still be corner cases. So perhaps
> > >> we can queue this on a temporary branch which we can use to submit fixes
> > >> in case of fallout.
> > >> 
> > >> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
> > >> headers.
> > >> 
> > >> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
> > >> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
> > >> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com
> > >
> > > I believe Arnd can take it through his tree for headers as DRM part is 
> > > Acked already.
> > 
> > I've applied it yesterday and not seen any regression reports so far.
> 
> Probably because the immutable tag is already in -next?

Is there any?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 0/2] Cleanup io.h

[Andy Shevchenko]

On Fri, Feb 28, 2025 at 08:41:33PM +0200, Andy Shevchenko wrote:
> On Fri, Feb 28, 2025 at 07:41:55PM +0200, Raag Jadav wrote:
> > On Fri, Feb 28, 2025 at 06:11:16PM +0100, Arnd Bergmann wrote:
> > > On Thu, Feb 27, 2025, at 16:25, Andy Shevchenko wrote:
> > > > On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
> > > >> This series attempts to cleanup io.h with "include what you use" approach.
> > > >> This depends on changes available on immutable tag[1].
> > > >> 
> > > >> Although this series is too trivial in the grand scheme of things, it is
> > > >> still a tiny step towards untangling core headers. I have success results
> > > >> from LKP for this series but there can still be corner cases. So perhaps
> > > >> we can queue this on a temporary branch which we can use to submit fixes
> > > >> in case of fallout.
> > > >> 
> > > >> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
> > > >> headers.
> > > >> 
> > > >> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
> > > >> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
> > > >> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com
> > > >
> > > > I believe Arnd can take it through his tree for headers as DRM part is 
> > > > Acked already.
> > > 
> > > I've applied it yesterday and not seen any regression reports so far.
> > 
> > Probably because the immutable tag is already in -next?
> 
> Is there any?

Ah, you mean devres related?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 0/2] Cleanup io.h

[Raag Jadav]

On Fri, Feb 28, 2025 at 08:42:10PM +0200, Andy Shevchenko wrote:
> On Fri, Feb 28, 2025 at 08:41:33PM +0200, Andy Shevchenko wrote:
> > On Fri, Feb 28, 2025 at 07:41:55PM +0200, Raag Jadav wrote:
> > > On Fri, Feb 28, 2025 at 06:11:16PM +0100, Arnd Bergmann wrote:
> > > > On Thu, Feb 27, 2025, at 16:25, Andy Shevchenko wrote:
> > > > > On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
> > > > >> This series attempts to cleanup io.h with "include what you use" approach.
> > > > >> This depends on changes available on immutable tag[1].
> > > > >> 
> > > > >> Although this series is too trivial in the grand scheme of things, it is
> > > > >> still a tiny step towards untangling core headers. I have success results
> > > > >> from LKP for this series but there can still be corner cases. So perhaps
> > > > >> we can queue this on a temporary branch which we can use to submit fixes
> > > > >> in case of fallout.
> > > > >> 
> > > > >> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
> > > > >> headers.
> > > > >> 
> > > > >> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
> > > > >> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
> > > > >> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com
> > > > >
> > > > > I believe Arnd can take it through his tree for headers as DRM part is 
> > > > > Acked already.
> > > > 
> > > > I've applied it yesterday and not seen any regression reports so far.
> > > 
> > > Probably because the immutable tag is already in -next?
> > 
> > Is there any?
> 
> Ah, you mean devres related?

Yeah, couldn't find it on Arnd's tree and I'm not sure if this series
works without it.

Raag

Re: [PATCH v3 0/2] Cleanup io.h

[Andy Shevchenko]

On Fri, Feb 28, 2025 at 08:45:26PM +0200, Raag Jadav wrote:
> On Fri, Feb 28, 2025 at 08:42:10PM +0200, Andy Shevchenko wrote:
> > On Fri, Feb 28, 2025 at 08:41:33PM +0200, Andy Shevchenko wrote:
> > > On Fri, Feb 28, 2025 at 07:41:55PM +0200, Raag Jadav wrote:
> > > > On Fri, Feb 28, 2025 at 06:11:16PM +0100, Arnd Bergmann wrote:
> > > > > On Thu, Feb 27, 2025, at 16:25, Andy Shevchenko wrote:
> > > > > > On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
> > > > > >> This series attempts to cleanup io.h with "include what you use" approach.
> > > > > >> This depends on changes available on immutable tag[1].
> > > > > >> 
> > > > > >> Although this series is too trivial in the grand scheme of things, it is
> > > > > >> still a tiny step towards untangling core headers. I have success results
> > > > > >> from LKP for this series but there can still be corner cases. So perhaps
> > > > > >> we can queue this on a temporary branch which we can use to submit fixes
> > > > > >> in case of fallout.
> > > > > >> 
> > > > > >> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
> > > > > >> headers.
> > > > > >> 
> > > > > >> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
> > > > > >> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
> > > > > >> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com
> > > > > >
> > > > > > I believe Arnd can take it through his tree for headers as DRM part is 
> > > > > > Acked already.
> > > > > 
> > > > > I've applied it yesterday and not seen any regression reports so far.
> > > > 
> > > > Probably because the immutable tag is already in -next?
> > > 
> > > Is there any?
> > 
> > Ah, you mean devres related?
> 
> Yeah, couldn't find it on Arnd's tree and I'm not sure if this series
> works without it.

But err.h is included in the io.h, no? Or did I misunderstand the point?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 0/2] Cleanup io.h

[Raag Jadav]

On Fri, Feb 28, 2025 at 08:52:51PM +0200, Andy Shevchenko wrote:
> On Fri, Feb 28, 2025 at 08:45:26PM +0200, Raag Jadav wrote:
> > On Fri, Feb 28, 2025 at 08:42:10PM +0200, Andy Shevchenko wrote:
> > > On Fri, Feb 28, 2025 at 08:41:33PM +0200, Andy Shevchenko wrote:
> > > > On Fri, Feb 28, 2025 at 07:41:55PM +0200, Raag Jadav wrote:
> > > > > On Fri, Feb 28, 2025 at 06:11:16PM +0100, Arnd Bergmann wrote:
> > > > > > On Thu, Feb 27, 2025, at 16:25, Andy Shevchenko wrote:
> > > > > > > On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
> > > > > > >> This series attempts to cleanup io.h with "include what you use" approach.
> > > > > > >> This depends on changes available on immutable tag[1].
> > > > > > >> 
> > > > > > >> Although this series is too trivial in the grand scheme of things, it is
> > > > > > >> still a tiny step towards untangling core headers. I have success results
> > > > > > >> from LKP for this series but there can still be corner cases. So perhaps
> > > > > > >> we can queue this on a temporary branch which we can use to submit fixes
> > > > > > >> in case of fallout.
> > > > > > >> 
> > > > > > >> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
> > > > > > >> headers.
> > > > > > >> 
> > > > > > >> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
> > > > > > >> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
> > > > > > >> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com
> > > > > > >
> > > > > > > I believe Arnd can take it through his tree for headers as DRM part is 
> > > > > > > Acked already.
> > > > > > 
> > > > > > I've applied it yesterday and not seen any regression reports so far.
> > > > > 
> > > > > Probably because the immutable tag is already in -next?
> > > > 
> > > > Is there any?
> > > 
> > > Ah, you mean devres related?
> > 
> > Yeah, couldn't find it on Arnd's tree and I'm not sure if this series
> > works without it.
> 
> But err.h is included in the io.h, no? Or did I misunderstand the point?

First patch on the immutable tag moves IOMEM_ERR_PTR() to err.h and here
we're dropping err.h from io.h. So without the tag this series will probably
break IOMEM_ERR_PTR().

Raag

Re: [PATCH v3 0/2] Cleanup io.h

[Andy Shevchenko]

On Fri, Feb 28, 2025 at 09:08:15PM +0200, Raag Jadav wrote:
> On Fri, Feb 28, 2025 at 08:52:51PM +0200, Andy Shevchenko wrote:
> > On Fri, Feb 28, 2025 at 08:45:26PM +0200, Raag Jadav wrote:
> > > On Fri, Feb 28, 2025 at 08:42:10PM +0200, Andy Shevchenko wrote:
> > > > On Fri, Feb 28, 2025 at 08:41:33PM +0200, Andy Shevchenko wrote:
> > > > > On Fri, Feb 28, 2025 at 07:41:55PM +0200, Raag Jadav wrote:
> > > > > > On Fri, Feb 28, 2025 at 06:11:16PM +0100, Arnd Bergmann wrote:
> > > > > > > On Thu, Feb 27, 2025, at 16:25, Andy Shevchenko wrote:
> > > > > > > > On Thu, Feb 27, 2025 at 12:37:45PM +0530, Raag Jadav wrote:
> > > > > > > >> This series attempts to cleanup io.h with "include what you use" approach.
> > > > > > > >> This depends on changes available on immutable tag[1].
> > > > > > > >> 
> > > > > > > >> Although this series is too trivial in the grand scheme of things, it is
> > > > > > > >> still a tiny step towards untangling core headers. I have success results
> > > > > > > >> from LKP for this series but there can still be corner cases. So perhaps
> > > > > > > >> we can queue this on a temporary branch which we can use to submit fixes
> > > > > > > >> in case of fallout.
> > > > > > > >> 
> > > > > > > >> Future plan is to use the excellent analysis[2][3] by Arnd to cleanup other
> > > > > > > >> headers.
> > > > > > > >> 
> > > > > > > >> [1] https://lore.kernel.org/r/Z7xGpz3Q4Zj6YHx7@black.fi.intel.com
> > > > > > > >> [2] https://lore.kernel.org/r/2342b516-2c6e-42e5-b4f4-579b280823ba@app.fastmail.com
> > > > > > > >> [3] https://lore.kernel.org/r/f6eb011b-40fb-409a-b2b2-a09d0e770bbd@app.fastmail.com
> > > > > > > >
> > > > > > > > I believe Arnd can take it through his tree for headers as DRM part is 
> > > > > > > > Acked already.
> > > > > > > 
> > > > > > > I've applied it yesterday and not seen any regression reports so far.
> > > > > > 
> > > > > > Probably because the immutable tag is already in -next?
> > > > > 
> > > > > Is there any?
> > > > 
> > > > Ah, you mean devres related?
> > > 
> > > Yeah, couldn't find it on Arnd's tree and I'm not sure if this series
> > > works without it.
> > 
> > But err.h is included in the io.h, no? Or did I misunderstand the point?
> 
> First patch on the immutable tag moves IOMEM_ERR_PTR() to err.h and here
> we're dropping err.h from io.h. So without the tag this series will probably
> break IOMEM_ERR_PTR().

I see, I think it might be due to some other includes that make this happen.
Whatever, I assume that Arnd heavily tested this anyway, so it's good to go
independently on the immutable tag..

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 0/2] Cleanup io.h

[Arnd Bergmann]

On Mon, Mar 3, 2025, at 08:48, Andy Shevchenko wrote:
> On Fri, Feb 28, 2025 at 09:08:15PM +0200, Raag Jadav wrote:
>> > > > Ah, you mean devres related?
>> > > 
>> > > Yeah, couldn't find it on Arnd's tree and I'm not sure if this series
>> > > works without it.
>> > 
>> > But err.h is included in the io.h, no? Or did I misunderstand the point?
>> 
>> First patch on the immutable tag moves IOMEM_ERR_PTR() to err.h and here
>> we're dropping err.h from io.h. So without the tag this series will probably
>> break IOMEM_ERR_PTR().
>
> I see, I think it might be due to some other includes that make this happen.
> Whatever, I assume that Arnd heavily tested this anyway, so it's good to go
> independently on the immutable tag..

I see that err.h gets included through at least linux/string.h,
linux/logic_pio.h and (depending on the architecture architectures)
asm/page.h, so there is no huge risk of something breaking here ;-)

Ideally all of the above should be removed here, but to do
it right, the linux/pgtable.h dependency needs to also be replaced
with a smaller pgprot_t specific one, which takes a bit of
cross-platform work as the definition is not in a consistent
place at the moment.

The change below still builds fine, and that likely indicates
that the same headers are still included from either asm/io.h
or asm/pgtable.h on the architectures I'm testing.

    Arnd

----
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 402020b23423..60a162591072 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -7,16 +7,16 @@
 #ifndef __ASM_GENERIC_IO_H
 #define __ASM_GENERIC_IO_H
 
-#include <asm/page.h> /* I/O is all done through memory accesses */
-#include <linux/string.h> /* for memset() and memcpy() */
 #include <linux/sizes.h>
 #include <linux/types.h>
 #include <linux/instruction_pointer.h>
+#include <linux/compiler.h>
 
 #ifdef CONFIG_GENERIC_IOMAP
 #include <asm-generic/iomap.h>
 #endif
 
+#include <asm/byteorder.h>
 #include <asm/mmiowb.h>
 #include <asm-generic/pci_iomap.h>
 
diff --git a/include/linux/logic_pio.h b/include/linux/logic_pio.h
index 8f1a9408302f..a83286bf13ab 100644
--- a/include/linux/logic_pio.h
+++ b/include/linux/logic_pio.h
@@ -8,7 +8,9 @@
 #ifndef __LINUX_LOGIC_PIO_H
 #define __LINUX_LOGIC_PIO_H
 
-#include <linux/fwnode.h>
+#include <linux/types.h>
+
+struct fwnode_handle;
 
 enum {
        LOGIC_PIO_INDIRECT,             /* Indirect IO flag */

Re: [PATCH v3 0/2] Cleanup io.h

[Andy Shevchenko]

On Mon, Mar 03, 2025 at 09:31:06AM +0100, Arnd Bergmann wrote:
> On Mon, Mar 3, 2025, at 08:48, Andy Shevchenko wrote:
> > On Fri, Feb 28, 2025 at 09:08:15PM +0200, Raag Jadav wrote:
> >> > > > Ah, you mean devres related?
> >> > > 
> >> > > Yeah, couldn't find it on Arnd's tree and I'm not sure if this series
> >> > > works without it.
> >> > 
> >> > But err.h is included in the io.h, no? Or did I misunderstand the point?
> >> 
> >> First patch on the immutable tag moves IOMEM_ERR_PTR() to err.h and here
> >> we're dropping err.h from io.h. So without the tag this series will probably
> >> break IOMEM_ERR_PTR().
> >
> > I see, I think it might be due to some other includes that make this happen.
> > Whatever, I assume that Arnd heavily tested this anyway, so it's good to go
> > independently on the immutable tag..
> 
> I see that err.h gets included through at least linux/string.h,
> linux/logic_pio.h and (depending on the architecture architectures)
> asm/page.h, so there is no huge risk of something breaking here ;-)
> 
> Ideally all of the above should be removed here, but to do
> it right, the linux/pgtable.h dependency needs to also be replaced
> with a smaller pgprot_t specific one, which takes a bit of
> cross-platform work as the definition is not in a consistent
> place at the moment.
> 
> The change below still builds fine, and that likely indicates
> that the same headers are still included from either asm/io.h
> or asm/pgtable.h on the architectures I'm testing.

Sounds even better. Can you submit a formal patch that other CIs will have
a chance to go through this?

-- 
With Best Regards,
Andy Shevchenko