linux-kernel - [PATCH v10 03/27] kallsyms: add static relationship between `KSYM_NAME_LEN{,

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Message-Id: <20220927131518.30000-4-ojeda@kernel.org>
Date:   Tue, 27 Sep 2022 15:14:34 +0200
From:   Miguel Ojeda <ojeda@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     rust-for-linux@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, patches@...ts.linux.dev,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Miguel Ojeda <ojeda@...nel.org>,
        Boqun Feng <boqun.feng@...il.com>
Subject: [PATCH v10 03/27] kallsyms: add static relationship between `KSYM_NAME_LEN{,_BUFFER}`

This adds a static assert to ensure `KSYM_NAME_LEN_BUFFER`
gets updated when `KSYM_NAME_LEN` changes.

The relationship used is one that keeps the new size (512+1)
close to the original buffer size (500).

Co-developed-by: Boqun Feng <boqun.feng@...il.com>
Signed-off-by: Boqun Feng <boqun.feng@...il.com>
Signed-off-by: Miguel Ojeda <ojeda@...nel.org>
---
 scripts/kallsyms.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 25e2fe5fbcd4..411ff5058b51 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -32,8 +32,18 @@
 
 #define KSYM_NAME_LEN		128
 
-/* A substantially bigger size than the current maximum. */
-#define KSYM_NAME_LEN_BUFFER	499
+/*
+ * A substantially bigger size than the current maximum.
+ *
+ * It cannot be defined as an expression because it gets stringified
+ * for the fscanf() format string. Therefore, a _Static_assert() is
+ * used instead to maintain the relationship with KSYM_NAME_LEN.
+ */
+#define KSYM_NAME_LEN_BUFFER	512
+_Static_assert(
+	KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
+	"Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"
+);
 
 struct sym_entry {
 	unsigned long long addr;
-- 
2.37.3