module: remove module_text_address()

Impact: Replace and remove risky (non-EXPORTed) API

module_text_address() returns a pointer to the module, which given locking
improvements in module.c, is useless except to test for NULL:

1) If the module can't go away, use __module_text_address.
2) Otherwise, just use is_module_text_address().

Cc: linux-mtd@lists.infradead.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/mtd/nand/nand_base.c

@@ -2720,14 +2720,14 @@ int nand_scan_tail(struct mtd_info *mtd)
 	return chip->scan_bbt(mtd);
 }
 
-/* module_text_address() isn't exported, and it's mostly a pointless
+/* is_module_text_address() isn't exported, and it's mostly a pointless
    test if this is a module _anyway_ -- they'd have to try _really_ hard
    to call us from in-kernel code if the core NAND support is modular. */
 #ifdef MODULE
 #define caller_is_module() (1)
 #else
 #define caller_is_module() \
-	module_text_address((unsigned long)__builtin_return_address(0))
+	is_module_text_address((unsigned long)__builtin_return_address(0))
 #endif
 
 /**

include/linux/module.h

@@ -362,8 +362,6 @@ static inline int module_is_live(struct module *mod)
 	return mod->state != MODULE_STATE_GOING;
 }
 
-/* Is this address in a module? (second is with no locks, for oops) */
-struct module *module_text_address(unsigned long addr);
 struct module *__module_text_address(unsigned long addr);
 struct module *__module_address(unsigned long addr);
 bool is_module_address(unsigned long addr);
@@ -496,11 +494,6 @@ search_module_extables(unsigned long addr)
 	return NULL;
 }
 
-static inline struct module *module_text_address(unsigned long addr)
-{
-	return NULL;
-}
-
 static inline struct module *__module_address(unsigned long addr)
 {
 	return NULL;

kernel/extable.c

@@ -58,14 +58,14 @@ __notrace_funcgraph int __kernel_text_address(unsigned long addr)
 {
 	if (core_kernel_text(addr))
 		return 1;
-	return __module_text_address(addr) != NULL;
+	return is_module_text_address(addr);
 }
 
 int kernel_text_address(unsigned long addr)
 {
 	if (core_kernel_text(addr))
 		return 1;
-	return module_text_address(addr) != NULL;
+	return is_module_text_address(addr);
 }
 
 /*
@@ -81,5 +81,5 @@ int func_ptr_is_kernel_text(void *ptr)
 	addr = (unsigned long) dereference_function_descriptor(ptr);
 	if (core_kernel_text(addr))
 		return 1;
-	return module_text_address(addr) != NULL;
+	return is_module_text_address(addr);
 }

kernel/module.c

@@ -908,8 +908,10 @@ void symbol_put_addr(void *addr)
 	if (core_kernel_text((unsigned long)addr))
 		return;
 
-	if (!(modaddr = module_text_address((unsigned long)addr)))
-		BUG();
+	/* module_text_address is safe here: we're supposed to have reference
+	 * to module from symbol_get, so it can't go away. */
+	modaddr = __module_text_address((unsigned long)addr);
+	BUG_ON(!modaddr);
 	module_put(modaddr);
 }
 EXPORT_SYMBOL_GPL(symbol_put_addr);
@@ -2821,17 +2823,6 @@ struct module *__module_text_address(unsigned long addr)
 	return mod;
 }
 
-struct module *module_text_address(unsigned long addr)
-{
-	struct module *mod;
-
-	preempt_disable();
-	mod = __module_text_address(addr);
-	preempt_enable();
-
-	return mod;
-}
-
 /* Don't grab lock, we're oopsing. */
 void print_modules(void)
 {