module: wrapper for symbol name.

This trivial wrapper adds clarity and makes the following patch
smaller.

Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

kernel/module.c

@@ -3627,6 +3627,11 @@ static inline int is_arm_mapping_symbol(const char *str)
 	       && (str[2] == '\0' || str[2] == '.');
 }
 
+static const char *symname(struct module *mod, unsigned int symnum)
+{
+	return mod->strtab + mod->symtab[symnum].st_name;
+}
+
 static const char *get_ksymbol(struct module *mod,
 			       unsigned long addr,
 			       unsigned long *size,
@@ -3649,15 +3654,15 @@ static const char *get_ksymbol(struct module *mod,
 
 		/* We ignore unnamed symbols: they're uninformative
 		 * and inserted at a whim. */
+		if (*symname(mod, i) == '\0'
+		    || is_arm_mapping_symbol(symname(mod, i)))
+			continue;
+
 		if (mod->symtab[i].st_value <= addr
-		    && mod->symtab[i].st_value > mod->symtab[best].st_value
-		    && *(mod->strtab + mod->symtab[i].st_name) != '\0'
-		    && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
+		    && mod->symtab[i].st_value > mod->symtab[best].st_value)
 			best = i;
 		if (mod->symtab[i].st_value > addr
-		    && mod->symtab[i].st_value < nextval
-		    && *(mod->strtab + mod->symtab[i].st_name) != '\0'
-		    && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
+		    && mod->symtab[i].st_value < nextval)
 			nextval = mod->symtab[i].st_value;
 	}
 
@@ -3668,7 +3673,7 @@ static const char *get_ksymbol(struct module *mod,
 		*size = nextval - mod->symtab[best].st_value;
 	if (offset)
 		*offset = addr - mod->symtab[best].st_value;
-	return mod->strtab + mod->symtab[best].st_name;
+	return symname(mod, best);
 }
 
 /* For kallsyms to ask for address resolution.  NULL means not found.  Careful
@@ -3763,8 +3768,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 		if (symnum < mod->num_symtab) {
 			*value = mod->symtab[symnum].st_value;
 			*type = mod->symtab[symnum].st_info;
-			strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
-				KSYM_NAME_LEN);
+			strlcpy(name, symname(mod, symnum), KSYM_NAME_LEN);
 			strlcpy(module_name, mod->name, MODULE_NAME_LEN);
 			*exported = is_exported(name, *value, mod);
 			preempt_enable();
@@ -3781,7 +3785,7 @@ static unsigned long mod_find_symname(struct module *mod, const char *name)
 	unsigned int i;
 
 	for (i = 0; i < mod->num_symtab; i++)
-		if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
+		if (strcmp(name, symname(mod, i)) == 0 &&
 		    mod->symtab[i].st_info != 'U')
 			return mod->symtab[i].st_value;
 	return 0;
@@ -3825,7 +3829,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
 		for (i = 0; i < mod->num_symtab; i++) {
-			ret = fn(data, mod->strtab + mod->symtab[i].st_name,
+			ret = fn(data, symname(mod, i),
 				 mod, mod->symtab[i].st_value);
 			if (ret != 0)
 				return ret;