Message-ID: <CAK8P3a1XWK2AOBWmnc6LUZrvXqDWLK3uaw5eHgchwBmb9hMzoQ@mail.gmail.com>
Date:   Mon, 26 Mar 2018 17:18:14 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Deepa Dinamani <deepa.kernel@...il.com>
Cc:     kbuild test robot <fengguang.wu@...el.com>,
        Stephen Rothwell <sfr@...b.auug.org.au>, kbuild-all@...org,
        Thomas Gleixner <tglx@...utronix.de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [linux-next:master 7357/9340] drivers/s390/char/fs3270.c:337:10:
 error: implicit declaration of function 'compat_ptr'; did you mean 'complete'?

On Thu, Mar 22, 2018 at 9:03 PM, Deepa Dinamani <deepa.kernel@...il.com> wrote:
> On Wed, Mar 21, 2018 at 12:04 AM, Arnd Bergmann <arnd@...db.de> wrote:
>> On Wed, Mar 21, 2018 at 2:37 AM, Deepa Dinamani <deepa.kernel@...il.com> wrote:
>>> This does not have the recent s390 patch I sent out to be applied on linux-next.
>>> This is not yet in linux-next.
>>>
>>> ------
>>>
>>> s390: Use asm/compat.h instead of linux/compat.h
>>>
>>> Include asm/compat.h directly for uses of compat_ptr.
>>> This includes the compat defines when CONFIG_COMPAT is
>>> not on.
>>>
>>> Also make compat data structure definitions conditional on
>>> CONFIG_COMPAT, to remove circular include dependencies in
>>> elf.h
>>>
>>> Cc: David Hildenbrand <david@...hat.com>
>>> Cc: linux-s390@...r.kernel.org
>>> Signed-off-by: Deepa Dinamani <deepa.kernel@...il.com>
>>
>> I have an increasingly bad feeling about this workaround, I think we need
>> to try harder to make linux/compat.h contain whatever is expected and
>> provide everything that asm/compat.h does.
>
> This is my plan, But, I was planning to get rid of this by posting
> individual patches to specific architectures after this series was
> merged to keep this series less complicated.
> Problem comes from including compat code even when CONFIG_COMPAT is not on.
>
>> Generally it is expected that including linux/foo.h is a strict superset of
>> asm/foo.h, and you should use the former in device drivers.
>
> Right. I was also hesitant about this change. But, in this particular
> case, these are only s390 drivers that are not built on any other
> architectures.
> So I thought this should be okay. Also, I plan to clean this up in the
> architecture specific patches.
>
> If you still prefer fixing these now rather than later, then I can
> give it another try and post an update.

I've applied a different fix for now, see below.

I'll give it some more testing, but this solves both the arm64 and s390
issues I saw earlier, and lets us always include linux/compat.h instead
of having to include asm/compat.h.

Let me know if you see a problem with that one.

       Arnd

commit d1a353a4a8cce86c7651a8011cc860a921b850bc
Author: Arnd Bergmann <arnd@...db.de>
Date:   Mon Mar 26 16:59:15 2018 +0200

    compat: add an asm-generic/compat.h file

    We have a couple of files that try to include asm/compat.h on
    architectures where this is available. Those should generally use the
    higher-level linux/compat.h file, but that in turn fails to include
    asm/compat.h when CONFIG_COMPAT is disabled, unless we can provide
    that header on all architectures.

    This adds the asm/compat.h for all remaining architectures to
    simplify the dependencies.

    Architectures that are getting removed in linux-4.17 are not changed
    here, to avoid needless conflicts with the removal patches. Those
    architectures are broken by this patch, but we have already shown
    that they have no users.

    Signed-off-by: Arnd Bergmann <arnd@...db.de>

diff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild
index 9b68790013e2..0580cb8c84b2 100644
--- a/arch/alpha/include/asm/Kbuild
+++ b/arch/alpha/include/asm/Kbuild
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0


+generic-y += compat.h
 generic-y += exec.h
 generic-y += export.h
 generic-y += fb.h
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 4bd5d4369e05..d51bc22e8795 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 generic-y += bugs.h
+generic-y += compat.h
 generic-y += device.h
 generic-y += div64.h
 generic-y += emergency-restart.h
diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
index 873e3c189279..1d66db9c9db5 100644
--- a/arch/arm/include/asm/Kbuild
+++ b/arch/arm/include/asm/Kbuild
@@ -1,3 +1,4 @@
+generic-y += compat.h
 generic-y += current.h
 generic-y += early_ioremap.h
 generic-y += emergency-restart.h
diff --git a/arch/c6x/include/asm/Kbuild b/arch/c6x/include/asm/Kbuild
index fd4c840de837..24037486317c 100644
--- a/arch/c6x/include/asm/Kbuild
+++ b/arch/c6x/include/asm/Kbuild
@@ -1,6 +1,7 @@
 generic-y += atomic.h
 generic-y += barrier.h
 generic-y += bugs.h
+generic-y += compat.h
 generic-y += current.h
 generic-y += device.h
 generic-y += div64.h
diff --git a/arch/h8300/include/asm/Kbuild b/arch/h8300/include/asm/Kbuild
index 14bac06b7116..a5d0b2991f47 100644
--- a/arch/h8300/include/asm/Kbuild
+++ b/arch/h8300/include/asm/Kbuild
@@ -3,6 +3,7 @@ generic-y += barrier.h
 generic-y += bugs.h
 generic-y += cacheflush.h
 generic-y += checksum.h
+generic-y += compat.h
 generic-y += current.h
 generic-y += delay.h
 generic-y += device.h
diff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild
index e9743f689fb8..dd2fd9c0d292 100644
--- a/arch/hexagon/include/asm/Kbuild
+++ b/arch/hexagon/include/asm/Kbuild
@@ -2,6 +2,7 @@
 generic-y += barrier.h
 generic-y += bug.h
 generic-y += bugs.h
+generic-y += compat.h
 generic-y += current.h
 generic-y += device.h
 generic-y += div64.h
diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild
index 6dd867873364..557bbc8ba9f5 100644
--- a/arch/ia64/include/asm/Kbuild
+++ b/arch/ia64/include/asm/Kbuild
@@ -1,3 +1,4 @@
+generic-y += compat.h
 generic-y += exec.h
 generic-y += irq_work.h
 generic-y += mcs_spinlock.h
diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild
index 88a9d27df1ac..4d8d68c4e3dd 100644
--- a/arch/m68k/include/asm/Kbuild
+++ b/arch/m68k/include/asm/Kbuild
@@ -1,4 +1,5 @@
 generic-y += barrier.h
+generic-y += compat.h
 generic-y += device.h
 generic-y += emergency-restart.h
 generic-y += exec.h
diff --git a/arch/microblaze/include/asm/Kbuild
b/arch/microblaze/include/asm/Kbuild
index 3c80a5a308ed..fe6a6c6e5003 100644
--- a/arch/microblaze/include/asm/Kbuild
+++ b/arch/microblaze/include/asm/Kbuild
@@ -2,6 +2,7 @@ generic-y += barrier.h
 generic-y += bitops.h
 generic-y += bug.h
 generic-y += bugs.h
+generic-y += compat.h
 generic-y += device.h
 generic-y += div64.h
 generic-y += emergency-restart.h
diff --git a/arch/nios2/include/asm/Kbuild b/arch/nios2/include/asm/Kbuild
index d232da2cbb38..64ed3d656956 100644
--- a/arch/nios2/include/asm/Kbuild
+++ b/arch/nios2/include/asm/Kbuild
@@ -4,6 +4,7 @@ generic-y += bitops.h
 generic-y += bug.h
 generic-y += bugs.h
 generic-y += cmpxchg.h
+generic-y += compat.h
 generic-y += current.h
 generic-y += device.h
 generic-y += div64.h
diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild
index f05c722a21f8..65964d390b10 100644
--- a/arch/openrisc/include/asm/Kbuild
+++ b/arch/openrisc/include/asm/Kbuild
@@ -2,6 +2,7 @@ generic-y += barrier.h
 generic-y += bug.h
 generic-y += bugs.h
 generic-y += checksum.h
+generic-y += compat.h
 generic-y += current.h
 generic-y += device.h
 generic-y += div64.h
diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild
index 1efcce74997b..46dd82ab2c29 100644
--- a/arch/sh/include/asm/Kbuild
+++ b/arch/sh/include/asm/Kbuild
@@ -1,3 +1,4 @@
+generic-y += compat.h
 generic-y += current.h
 generic-y += delay.h
 generic-y += div64.h
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index bb5a196c3061..b10dde6cb793 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -1,6 +1,7 @@
 generic-y += barrier.h
 generic-y += bpf_perf_event.h
 generic-y += bug.h
+generic-y += compat.h
 generic-y += current.h
 generic-y += delay.h
 generic-y += device.h
diff --git a/arch/unicore32/include/asm/Kbuild
b/arch/unicore32/include/asm/Kbuild
index 6f70c76c81fc..bfc7abe77905 100644
--- a/arch/unicore32/include/asm/Kbuild
+++ b/arch/unicore32/include/asm/Kbuild
@@ -1,5 +1,6 @@
 generic-y += atomic.h
 generic-y += bugs.h
+generic-y += compat.h
 generic-y += current.h
 generic-y += device.h
 generic-y += div64.h
diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild
index 436b20337168..e5e1e61c538c 100644
--- a/arch/xtensa/include/asm/Kbuild
+++ b/arch/xtensa/include/asm/Kbuild
@@ -1,4 +1,5 @@
 generic-y += bug.h
+generic-y += compat.h
 generic-y += device.h
 generic-y += div64.h
 generic-y += dma-contiguous.h
diff --git a/include/asm-generic/compat.h b/include/asm-generic/compat.h
new file mode 100644
index 000000000000..28819451b6d1
--- /dev/null
+++ b/include/asm-generic/compat.h
@@ -0,0 +1,3 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* This is an empty stub for 32-bit-only architectures */
diff --git a/include/linux/compat.h b/include/linux/compat.h
index e291096dc937..94291c3e67dc 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -17,8 +17,9 @@
 #include <linux/aio_abi.h> /* for aio_context_t */
 #include <linux/unistd.h>

-#ifdef CONFIG_COMPAT
 #include <asm/compat.h>
+
+#ifdef CONFIG_COMPAT
 #include <asm/siginfo.h>
 #include <asm/signal.h>
 #endif

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