diff mbox series

[3/3] include/uapi/linux/swab: Fix potentially missing __always_inline

Message ID 20210727141119.19812-4-pavo.banicevic@sartura.hr (mailing list archive)
State New, archived
Headers show
Series Address compilation of eBPF related software with clang compiler on arm architecture | expand

Commit Message

Pavo Banicevic July 27, 2021, 2:11 p.m. UTC 
From: Matt Redfearn <matt.redfearn@mips.com>

Commit bc27fb68aaad ("include/uapi/linux/byteorder, swab: force inlining
of some byteswap operations") added __always_inline to swab functions
and commit 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to
userspace headers") added a definition of __always_inline for use in
exported headers when the kernel's compiler.h is not available.

However, since swab.h does not include stddef.h, if the header soup does
not indirectly include it, the definition of __always_inline is missing,
resulting in a compilation failure, which was observed compiling the
perf tool using exported headers containing this commit:

In file included from /usr/include/linux/byteorder/little_endian.h:12:0,
                 from /usr/include/asm/byteorder.h:14,
                 from tools/include/uapi/linux/perf_event.h:20,
                 from perf.h:8,
                 from builtin-bench.c:18:
/usr/include/linux/swab.h:160:8: error: unknown type name `__always_inline'
 static __always_inline __u16 __swab16p(const __u16 *p)

Fix this by replacing the inclusion of linux/compiler.h with
linux/stddef.h to ensure that we pick up that definition if required,
without relying on it's indirect inclusion. compiler.h is then included
indirectly, via stddef.h.

Fixes: 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to userspace headers")

Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
---
 include/uapi/linux/swab.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Petr Vaněk July 28, 2021, 1:49 p.m. UTC | #1 
On Tue, Jul 27, 2021 at 04:11:19PM +0200, Pavo Banicevic wrote:
> From: Matt Redfearn <matt.redfearn@mips.com>
> 
> Commit bc27fb68aaad ("include/uapi/linux/byteorder, swab: force inlining
> of some byteswap operations") added __always_inline to swab functions
> and commit 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to
> userspace headers") added a definition of __always_inline for use in
> exported headers when the kernel's compiler.h is not available.
> 
> However, since swab.h does not include stddef.h, if the header soup does
> not indirectly include it, the definition of __always_inline is missing,
> resulting in a compilation failure, which was observed compiling the
> perf tool using exported headers containing this commit:
> 
> In file included from /usr/include/linux/byteorder/little_endian.h:12:0,
>                  from /usr/include/asm/byteorder.h:14,
>                  from tools/include/uapi/linux/perf_event.h:20,
>                  from perf.h:8,
>                  from builtin-bench.c:18:
> /usr/include/linux/swab.h:160:8: error: unknown type name `__always_inline'
>  static __always_inline __u16 __swab16p(const __u16 *p)
> 
> Fix this by replacing the inclusion of linux/compiler.h with
> linux/stddef.h to ensure that we pick up that definition if required,
> without relying on it's indirect inclusion. compiler.h is then included
> indirectly, via stddef.h.
> 
> Fixes: 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to userspace headers")
> 
> Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
> ---

I use this patch in order to fix __always_inline issue for kernels
5.12+, see https://lore.kernel.org/lkml/YPGXXt6Z3O1W0AYS@arkam/ .
I believe this is the correct solution.

Reviewed-by: Petr Vaněk <arkamar@atlas.cz>
diff mbox series

Patch

diff --git a/include/uapi/linux/swab.h b/include/uapi/linux/swab.h
index 7272f85d6d6a..3736f2fe1541 100644
--- a/include/uapi/linux/swab.h
+++ b/include/uapi/linux/swab.h
@@ -3,7 +3,7 @@ 
 #define _UAPI_LINUX_SWAB_H
 
 #include <linux/types.h>
-#include <linux/compiler.h>
+#include <linux/stddef.h>
 #include <asm/bitsperlong.h>
 #include <asm/swab.h>