linux-kernel - [PATCH 3.2 020/104] modpost: reduce visibility of symbols and constify r/o arrays

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Message-ID: <lsq.1520823814.677872617@decadent.org.uk>
Date:   Mon, 12 Mar 2018 03:03:34 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Mathias Krause" <minipli@...glemail.com>,
        "Rusty Russell" <rusty@...tcorp.com.au>
Subject: [PATCH 3.2 020/104] modpost: reduce visibility of symbols and
 constify r/o arrays

3.2.101-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Krause <minipli@...glemail.com>

commit 7a3ee7538598e0d60e6aa87dcf34a4e8a0adebc2 upstream.

Internally used symbols of modpost don't need to be externally visible;
make them static. Also constify the string arrays so they resist in the
r/o section instead of being runtime writable.

Those changes lead to a small size reduction as can be seen below:

   text    data     bss     dec     hex filename
  51381    2640   12416   66437   10385 scripts/mod/modpost.old
  51765    2224   12416   66405   10365 scripts/mod/modpost.new

Signed-off-by: Mathias Krause <minipli@...glemail.com>
Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 scripts/mod/modpost.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -28,9 +28,9 @@
 
 
 /* Are we using CONFIG_MODVERSIONS? */
-int modversions = 0;
+static int modversions = 0;
 /* Warn about undefined symbols? (do so if we have vmlinux) */
-int have_vmlinux = 0;
+static int have_vmlinux = 0;
 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
 static int all_versions = 0;
 /* If we are modposting external module set to 1 */
@@ -225,7 +225,7 @@ static struct symbol *find_symbol(const
 	return NULL;
 }
 
-static struct {
+static const struct {
 	const char *str;
 	enum export export;
 } export_list[] = {
@@ -816,7 +816,7 @@ static int match(const char *sym, const
 }
 
 /* sections that we do not want to do full section mismatch check on */
-static const char *section_white_list[] =
+static const char *const section_white_list[] =
 {
 	".comment*",
 	".debug*",
@@ -888,17 +888,18 @@ static void check_section(const char *mo
 #define MEM_EXIT_SECTIONS  ".memexit.*"
 
 /* init data sections */
-static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
+static const char *const init_data_sections[] =
+	{ ALL_INIT_DATA_SECTIONS, NULL };
 
 /* all init sections */
-static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
+static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
 
 /* All init and exit sections (code + data) */
-static const char *init_exit_sections[] =
+static const char *const init_exit_sections[] =
 	{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
 
 /* data section */
-static const char *data_sections[] = { DATA_SECTIONS, NULL };
+static const char *const data_sections[] = { DATA_SECTIONS, NULL };
 
 
 /* symbols in .data that may refer to init/exit sections */
@@ -912,8 +913,8 @@ static const char *data_sections[] = { D
 	"*_probe_one",							\
 	"*_console"
 
-static const char *head_sections[] = { ".head.text*", NULL };
-static const char *linker_symbols[] =
+static const char *const head_sections[] = { ".head.text*", NULL };
+static const char *const linker_symbols[] =
 	{ "__init_begin", "_sinittext", "_einittext", NULL };
 
 enum mismatch {
@@ -935,7 +936,7 @@ struct sectioncheck {
 	const char *symbol_white_list[20];
 };
 
-const struct sectioncheck sectioncheck[] = {
+static const struct sectioncheck sectioncheck[] = {
 /* Do not reference init/exit code/data from
  * normal code and data
  */