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From:   Petr Vorel <petr.vorel@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     Petr Vorel <petr.vorel@gmail.com>, Rich Felker <dalias@aerifal.cx>,
        musl@lists.openwall.com, Peter Korsgaard <peter@korsgaard.com>,
        Baruch Siach <baruch@tkos.co.il>,
        Florian Weimer <fweimer@redhat.com>, linux-api@vger.kernel.org,
        libc-alpha@sourceware.org
Subject: [PATCH v3 1/1] uapi: Move constants from <linux/kernel.h> to <linux/const.h>
Date:   Thu, 15 Oct 2020 21:00:13 +0200
Message-Id: <20201015190013.8901-1-petr.vorel@gmail.com>
MIME-Version: 1.0
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Precedence: bulk

and include <linux/const.h> in UAPI headers instead of <linux/kernel.h>.

The reason is to avoid indirect <linux/sysinfo.h> include when using
some network headers: <linux/netlink.h> or others -> <linux/kernel.h>
-> <linux/sysinfo.h>.

This indirect include causes on MUSL redefinition of struct sysinfo when
included both <sys/sysinfo.h> and some of UAPI headers:

In file included from x86_64-buildroot-linux-musl/sysroot/usr/include/linux/kernel.h:5,
                 from x86_64-buildroot-linux-musl/sysroot/usr/include/linux/netlink.h:5,
                 from ../include/tst_netlink.h:14,
                 from tst_crypto.c:13:
x86_64-buildroot-linux-musl/sysroot/usr/include/linux/sysinfo.h:8:8: error: redefinition of ‘struct sysinfo’
 struct sysinfo {
        ^~~~~~~
In file included from ../include/tst_safe_macros.h:15,
                 from ../include/tst_test.h:93,
                 from tst_crypto.c:11:
x86_64-buildroot-linux-musl/sysroot/usr/include/sys/sysinfo.h:10:8: note: originally defined here

Suggested-by: Rich Felker <dalias@aerifal.cx>
Signed-off-by: Petr Vorel <petr.vorel@gmail.com>
---
Changes v2->v3:
* Move things to <linux/const.h> instead of creating new header
<linux/align.h>.

Kind regards,
Petr

 include/uapi/linux/const.h              | 5 +++++
 include/uapi/linux/ethtool.h            | 2 +-
 include/uapi/linux/kernel.h             | 9 +--------
 include/uapi/linux/lightnvm.h           | 2 +-
 include/uapi/linux/mroute6.h            | 2 +-
 include/uapi/linux/netfilter/x_tables.h | 2 +-
 include/uapi/linux/netlink.h            | 2 +-
 include/uapi/linux/sysctl.h             | 2 +-
 8 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/include/uapi/linux/const.h b/include/uapi/linux/const.h
index 5ed721ad5b19..af2a44c08683 100644
--- a/include/uapi/linux/const.h
+++ b/include/uapi/linux/const.h
@@ -28,4 +28,9 @@
 #define _BITUL(x)	(_UL(1) << (x))
 #define _BITULL(x)	(_ULL(1) << (x))
 
+#define __ALIGN_KERNEL(x, a)		__ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
+#define __ALIGN_KERNEL_MASK(x, mask)	(((x) + (mask)) & ~(mask))
+
+#define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+
 #endif /* _UAPI_LINUX_CONST_H */
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index b4f2d134e713..0a9cced74e6d 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -14,7 +14,7 @@
 #ifndef _UAPI_LINUX_ETHTOOL_H
 #define _UAPI_LINUX_ETHTOOL_H
 
-#include <linux/kernel.h>
+#include <linux/const.h>
 #include <linux/types.h>
 #include <linux/if_ether.h>
 
diff --git a/include/uapi/linux/kernel.h b/include/uapi/linux/kernel.h
index 0ff8f7477847..fadf2db71fe8 100644
--- a/include/uapi/linux/kernel.h
+++ b/include/uapi/linux/kernel.h
@@ -3,13 +3,6 @@
 #define _UAPI_LINUX_KERNEL_H
 
 #include <linux/sysinfo.h>
-
-/*
- * 'kernel.h' contains some often-used function prototypes etc
- */
-#define __ALIGN_KERNEL(x, a)		__ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
-#define __ALIGN_KERNEL_MASK(x, mask)	(((x) + (mask)) & ~(mask))
-
-#define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+#include <linux/const.h>
 
 #endif /* _UAPI_LINUX_KERNEL_H */
diff --git a/include/uapi/linux/lightnvm.h b/include/uapi/linux/lightnvm.h
index f9a1be7fc696..ead2e72e5c88 100644
--- a/include/uapi/linux/lightnvm.h
+++ b/include/uapi/linux/lightnvm.h
@@ -21,7 +21,7 @@
 #define _UAPI_LINUX_LIGHTNVM_H
 
 #ifdef __KERNEL__
-#include <linux/kernel.h>
+#include <linux/const.h>
 #include <linux/ioctl.h>
 #else /* __KERNEL__ */
 #include <stdio.h>
diff --git a/include/uapi/linux/mroute6.h b/include/uapi/linux/mroute6.h
index c36177a86516..a1fd6173e2db 100644
--- a/include/uapi/linux/mroute6.h
+++ b/include/uapi/linux/mroute6.h
@@ -2,7 +2,7 @@
 #ifndef _UAPI__LINUX_MROUTE6_H
 #define _UAPI__LINUX_MROUTE6_H
 
-#include <linux/kernel.h>
+#include <linux/const.h>
 #include <linux/types.h>
 #include <linux/sockios.h>
 #include <linux/in6.h>		/* For struct sockaddr_in6. */
diff --git a/include/uapi/linux/netfilter/x_tables.h b/include/uapi/linux/netfilter/x_tables.h
index a8283f7dbc51..b8c6bb233ac1 100644
--- a/include/uapi/linux/netfilter/x_tables.h
+++ b/include/uapi/linux/netfilter/x_tables.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 #ifndef _UAPI_X_TABLES_H
 #define _UAPI_X_TABLES_H
-#include <linux/kernel.h>
+#include <linux/const.h>
 #include <linux/types.h>
 
 #define XT_FUNCTION_MAXNAMELEN 30
diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h
index eac8a6a648ea..7ba6d3b9cdec 100644
--- a/include/uapi/linux/netlink.h
+++ b/include/uapi/linux/netlink.h
@@ -2,7 +2,7 @@
 #ifndef _UAPI__LINUX_NETLINK_H
 #define _UAPI__LINUX_NETLINK_H
 
-#include <linux/kernel.h>
+#include <linux/const.h>
 #include <linux/socket.h> /* for __kernel_sa_family_t */
 #include <linux/types.h>
 
diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
index 27c1ed2822e6..458179df9b27 100644
--- a/include/uapi/linux/sysctl.h
+++ b/include/uapi/linux/sysctl.h
@@ -23,7 +23,7 @@
 #ifndef _UAPI_LINUX_SYSCTL_H
 #define _UAPI_LINUX_SYSCTL_H
 
-#include <linux/kernel.h>
+#include <linux/const.h>
 #include <linux/types.h>
 #include <linux/compiler.h>
 
-- 
2.28.0