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From:   Ilya Leoshkevich <iii@linux.ibm.com>
To:     Al Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-kernel@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH 2/2] s390/uapi: Cover statfs padding by growing f_spare
Date:   Thu,  4 May 2023 16:40:21 +0200
Message-Id: <20230504144021.808932-3-iii@linux.ibm.com>
In-Reply-To: <20230504144021.808932-1-iii@linux.ibm.com>
References: <20230504144021.808932-1-iii@linux.ibm.com>
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pahole says:

	struct compat_statfs64 {
		...
		u32			f_spare[4];		/*    68    16 */
		/* size: 88, cachelines: 1, members: 12 */
		/* padding: 4 */

	struct statfs {
		...
		unsigned int		f_spare[4];		/*    68    16 */
		/* size: 88, cachelines: 1, members: 12 */
		/* padding: 4 */

	struct statfs64 {
		...
		unsigned int		f_spare[4];		/*    68    16 */
		/* size: 88, cachelines: 1, members: 12 */
		/* padding: 4 */

One has to keep the existence of padding in mind when working with
these structs. Grow f_spare arrays to 5 in order to simplify things.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 arch/s390/include/asm/compat.h      | 2 +-
 arch/s390/include/uapi/asm/statfs.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
index a386070f1d56..3cb9d813f022 100644
--- a/arch/s390/include/asm/compat.h
+++ b/arch/s390/include/asm/compat.h
@@ -112,7 +112,7 @@ struct compat_statfs64 {
 	u32		f_namelen;
 	u32		f_frsize;
 	u32		f_flags;
-	u32		f_spare[4];
+	u32		f_spare[5];
 };
 
 /*
diff --git a/arch/s390/include/uapi/asm/statfs.h b/arch/s390/include/uapi/asm/statfs.h
index 72604f7792c3..f85b50723dd3 100644
--- a/arch/s390/include/uapi/asm/statfs.h
+++ b/arch/s390/include/uapi/asm/statfs.h
@@ -30,7 +30,7 @@ struct statfs {
 	unsigned int	f_namelen;
 	unsigned int	f_frsize;
 	unsigned int	f_flags;
-	unsigned int	f_spare[4];
+	unsigned int	f_spare[5];
 };
 
 struct statfs64 {
@@ -45,7 +45,7 @@ struct statfs64 {
 	unsigned int	f_namelen;
 	unsigned int	f_frsize;
 	unsigned int	f_flags;
-	unsigned int	f_spare[4];
+	unsigned int	f_spare[5];
 };
 
 #endif
-- 
2.40.1