linux-kernel - Re: [PATCH 4/7] Ksplice: Add module_data_address (the analogue of module_text

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Message-ID: <alpine.DEB.2.00.0902041455140.32142@vinegar-pot.mit.edu>
Date:	Wed, 4 Feb 2009 15:48:36 -0500 (EST)
From:	Anders Kaseorg <andersk@....EDU>
To:	Rusty Russell <rusty@...tcorp.com.au>
cc:	Jeff Arnold <jbarnold@....edu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	Denys Vlasenko <vda.linux@...glemail.com>,
	Tim Abbott <tabbott@....edu>, Waseem Daher <wdaher@....edu>,
	Nikanth Karthikesan <knikanth@...e.de>
Subject: Re: [PATCH 4/7] Ksplice: Add module_data_address (the analogue of
 module_text_address)

On Wed, 4 Feb 2009, Rusty Russell wrote:
> Does this mean you really want module_data_address, or you actually want
> a module_address()?

Yeah, that works better.

diff --git a/include/linux/module.h b/include/linux/module.h
index ccbcfa7..42e7c8a 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -363,8 +363,8 @@ static inline int module_is_live(struct module *mod)
 /* 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_data_address(unsigned long addr);
-struct module *__module_data_address(unsigned long addr);
+struct module *module_address(unsigned long addr);
+struct module *__module_address(unsigned long addr);
 int is_module_address(unsigned long addr);

 static inline int within_module_core(unsigned long addr, struct module *mod)
diff --git a/kernel/module.c b/kernel/module.c
index b47772d..556112c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2773,35 +2773,32 @@ struct module *module_text_address(unsigned long addr)
 }
 EXPORT_SYMBOL_GPL(module_text_address);

-struct module *__module_data_address(unsigned long addr)
+__notrace_funcgraph struct module *__module_address(unsigned long addr)
 {
 	struct module *mod;

 	if (addr < module_addr_min || addr > module_addr_max)
 		return NULL;

-	list_for_each_entry(mod, &modules, list) {
-		if (within(addr, mod->module_core + mod->core_text_size,
-			   mod->core_size - mod->core_text_size) ||
-		    within(addr, mod->module_init + mod->init_text_size,
-			   mod->init_size - mod->init_text_size))
+	list_for_each_entry_rcu(mod, &modules, list)
+		if (within_module_core(addr, mod) ||
+		    within_module_init(addr, mod))
 			return mod;
-	}
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(__module_data_address);
+EXPORT_SYMBOL_GPL(__module_address);

-struct module *module_data_address(unsigned long addr)
+struct module *module_address(unsigned long addr)
 {
 	struct module *mod;

 	preempt_disable();
-	mod = __module_data_address(addr);
+	mod = __module_address(addr);
 	preempt_enable();

 	return mod;
 }
-EXPORT_SYMBOL_GPL(module_data_address);
+EXPORT_SYMBOL_GPL(module_address);

 /* Don't grab lock, we're oopsing. */
 void print_modules(void)
diff --git a/kernel/ksplice.c b/kernel/ksplice.c
index a3f21a6..0404e46 100644
--- a/kernel/ksplice.c
+++ b/kernel/ksplice.c
@@ -999,8 +999,7 @@ static void *map_writable(void *addr, size_t len)
 	int nr_pages = 2;
 	struct page *pages[2];

-	if (__module_text_address((unsigned long)addr) == NULL &&
-	    __module_data_address((unsigned long)addr) == NULL) {
+	if (__module_address((unsigned long)addr) == NULL) {
 		pages[0] = virt_to_page(addr);
 		WARN_ON(!PageReserved(pages[0]));
 		pages[1] = virt_to_page(addr + PAGE_SIZE);
@@ -1412,13 +1411,8 @@ static abort_t try_addr(struct ksplice_pack *pack,
 			enum run_pre_mode mode)
 {
 	abort_t ret;
-	const struct module *run_module;
+	const struct module *run_module = __module_address(run_addr);

-	if ((sect->flags & KSPLICE_SECTION_RODATA) != 0 ||
-	    (sect->flags & KSPLICE_SECTION_DATA) != 0)
-		run_module = __module_data_address(run_addr);
-	else
-		run_module = __module_text_address(run_addr);
 	if (run_module == pack->primary) {
 		ksdebug(pack, "run-pre: unexpected address %lx in primary "
 			"module %s for sect %s\n", run_addr, run_module->name,
--
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