linux-kernel - [PATCH 10/27] modpost: traverse unresolved symbols in order

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Date:   Mon, 25 Apr 2022 04:07:54 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     linux-kbuild@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Masahiro Yamada <masahiroy@...nel.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: [PATCH 10/27] modpost: traverse unresolved symbols in order

Currently, modpost manages unresolved in a singly liked list; it adds
a new node to the head, and traverses the list from new to old.

Use a doubly linked list to keep the order in the symbol table in the
ELF file.

Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
---

 scripts/mod/modpost.c | 20 ++++++++++++++------
 scripts/mod/modpost.h |  2 +-
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 1c7d2831e89d..e1eb188d6282 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -185,6 +185,8 @@ static struct module *new_module(const char *modname)
 	mod = NOFAIL(malloc(sizeof(*mod) + strlen(modname) + 1));
 	memset(mod, 0, sizeof(*mod));
 
+	INIT_LIST_HEAD(&mod->unresolved_symbols);
+
 	strcpy(mod->name, modname);
 	mod->is_vmlinux = (strcmp(modname, "vmlinux") == 0);
 	mod->gpl_compatible = true;
@@ -201,6 +203,7 @@ static struct module *new_module(const char *modname)
 
 struct symbol {
 	struct symbol *next;
+	struct list_head list;
 	struct module *module;
 	unsigned int crc;
 	bool crc_valid;
@@ -255,8 +258,12 @@ static struct symbol *new_symbol(const char *name, struct module *module,
 
 static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
 {
-	mod->unres = alloc_symbol(name, mod->unres);
-	mod->unres->weak = weak;
+	struct symbol *sym;
+
+	sym = alloc_symbol(name, NULL);
+	sym->weak = weak;
+
+	list_add_tail(&sym->list, &mod->unresolved_symbols);
 }
 
 static struct symbol *find_symbol(const char *name)
@@ -2147,7 +2154,7 @@ static void check_exports(struct module *mod)
 {
 	struct symbol *s, *exp;
 
-	for (s = mod->unres; s; s = s->next) {
+	list_for_each_entry(s, &mod->unresolved_symbols, list) {
 		const char *basename;
 		exp = find_symbol(s->name);
 		if (!exp) {
@@ -2268,7 +2275,7 @@ static void add_versions(struct buffer *b, struct module *mod)
 	buf_printf(b, "static const struct modversion_info ____versions[]\n");
 	buf_printf(b, "__used __section(\"__versions\") = {\n");
 
-	for (s = mod->unres; s; s = s->next) {
+	list_for_each_entry(s, &mod->unresolved_symbols, list) {
 		if (!s->module)
 			continue;
 		if (!s->crc_valid) {
@@ -2294,13 +2301,14 @@ static void add_depends(struct buffer *b, struct module *mod)
 	int first = 1;
 
 	/* Clear ->seen flag of modules that own symbols needed by this. */
-	for (s = mod->unres; s; s = s->next)
+	list_for_each_entry(s, &mod->unresolved_symbols, list) {
 		if (s->module)
 			s->module->seen = s->module->is_vmlinux;
+	}
 
 	buf_printf(b, "\n");
 	buf_printf(b, "MODULE_INFO(depends, \"");
-	for (s = mod->unres; s; s = s->next) {
+	list_for_each_entry(s, &mod->unresolved_symbols, list) {
 		const char *p;
 		if (!s->module)
 			continue;
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index c3b5d2f0e2bb..6a90bfc08458 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -117,7 +117,7 @@ struct namespace_list {
 struct module {
 	struct list_head list;
 	int gpl_compatible;
-	struct symbol *unres;
+	struct list_head unresolved_symbols;
 	bool from_dump;		/* true if module was loaded from *.symvers */
 	bool is_vmlinux;
 	bool seen;
-- 
2.32.0