linux-kernel - [PATCH v5 10/10] ARM: oabi-compat: fix oabi epoll sparse warning

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Date:   Mon, 26 Jul 2021 16:11:41 +0200
From:   Arnd Bergmann <arnd@...nel.org>
To:     Russell King <linux@...linux.org.uk>
Cc:     Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-arch@...r.kernel.org,
        linux-mm@...ck.org, Alexander Viro <viro@...iv.linux.org.uk>,
        Linus Walleij <linus.walleij@...aro.org>,
        kernel test robot <lkp@...el.com>
Subject: [PATCH v5 10/10] ARM: oabi-compat: fix oabi epoll sparse warning

From: Arnd Bergmann <arnd@...db.de>

As my patches change the oabi epoll definition, I received a report
from the kernel test robot about a pre-existing issue with a mismatched
__poll_t type.

The OABI code was correct when it was initially added in linux-2.16,
but a later (also correct) change to the generic __poll_t triggered a
type mismatch warning from sparse.

As __poll_t is always 32-bit bits wide and otherwise compatible, using
this instead of __u32 in the oabi_epoll_event definition is a valid
workaround.

Reported-by: kernel test robot <lkp@...el.com>
Fixes: 8ced390c2b18 ("define __poll_t, annotate constants")
Fixes: ee219b946e4b ("uapi: turn __poll_t sparse checks on by default")
Fixes: 687ad0191488 ("[ARM] 3109/1: old ABI compat: syscall wrappers for ABI impedance matching")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 arch/arm/kernel/sys_oabi-compat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c
index 223ee46b6e75..68112c172025 100644
--- a/arch/arm/kernel/sys_oabi-compat.c
+++ b/arch/arm/kernel/sys_oabi-compat.c
@@ -274,7 +274,7 @@ asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
 }
 
 struct oabi_epoll_event {
-	__u32 events;
+	__poll_t events;
 	__u64 data;
 } __attribute__ ((packed,aligned(4)));
 
-- 
2.29.2