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Date: Thu, 15 Mar 2012 22:48:55 +0800
From: Cong Wang <xiyou.wangcong@...il.com>
To: linux-kernel@...r.kernel.org
Cc: Andrew Morton <akpm@...ux-foundation.org>, Dennis1.Chen@....com,
Cong Wang <xiyou.wangcong@...il.com>,
Eric Dumazet <eric.dumazet@...il.com>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Rusty Russell <rusty@...tcorp.com.au>
Subject: [V3 PATCH 1/7] module: replace preempt_disable with rcu_read_lock_sched
V3: split the patches again and fix some typos
Currently we use preempt_disable() + *_rcu list operation to read module
list, it is more explicit to use rcu_read_lock_sched() directly. This change
should be trivial as rcu_read_lock_sched() is a wrapper of preempt_disable().
Cc: Eric Dumazet <eric.dumazet@...il.com>
Cc: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc: Rusty Russell <rusty@...tcorp.com.au>
Reported-by: <Dennis1.Chen@....com>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
kernel/module.c | 66 +++++++++++++++++++++++++++---------------------------
1 files changed, 33 insertions(+), 33 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 2c93276..6f6a3fd 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -91,7 +91,7 @@
/*
* Mutex protects:
- * 1) List of modules (also safely readable with preempt_disable),
+ * 1) List of modules (also safely readable with rcu_read_lock_sched),
* 2) module_use links,
* 3) module_addr_min/module_addr_max.
* (delete uses stop_machine/add uses RCU list operations). */
@@ -382,7 +382,7 @@ static bool find_symbol_in_section(const struct symsearch *syms,
}
/* Find a symbol and return it, along with, (optional) crc and
- * (optional) module which owns it. Needs preempt disabled or module_mutex. */
+ * (optional) module which owns it. Needs rcu_read_lock_sched or module_mutex. */
const struct kernel_symbol *find_symbol(const char *name,
struct module **owner,
const unsigned long **crc,
@@ -481,7 +481,7 @@ bool is_module_percpu_address(unsigned long addr)
struct module *mod;
unsigned int cpu;
- preempt_disable();
+ rcu_read_lock_sched();
list_for_each_entry_rcu(mod, &modules, list) {
if (!mod->percpu_size)
@@ -491,13 +491,13 @@ bool is_module_percpu_address(unsigned long addr)
if ((void *)addr >= start &&
(void *)addr < start + mod->percpu_size) {
- preempt_enable();
+ rcu_read_unlock_sched();
return true;
}
}
}
- preempt_enable();
+ rcu_read_unlock_sched();
return false;
}
@@ -869,11 +869,11 @@ void __symbol_put(const char *symbol)
{
struct module *owner;
- preempt_disable();
+ rcu_read_lock_sched();
if (!find_symbol(symbol, &owner, NULL, true, false))
BUG();
module_put(owner);
- preempt_enable();
+ rcu_read_unlock_sched();
}
EXPORT_SYMBOL(__symbol_put);
@@ -1810,11 +1810,11 @@ void *__symbol_get(const char *symbol)
struct module *owner;
const struct kernel_symbol *sym;
- preempt_disable();
+ rcu_read_lock_sched();
sym = find_symbol(symbol, &owner, NULL, true, true);
if (sym && strong_try_module_get(owner))
sym = NULL;
- preempt_enable();
+ rcu_read_unlock_sched();
return sym ? (void *)sym->value : NULL;
}
@@ -3130,7 +3130,7 @@ const char *module_address_lookup(unsigned long addr,
struct module *mod;
const char *ret = NULL;
- preempt_disable();
+ rcu_read_lock_sched();
list_for_each_entry_rcu(mod, &modules, list) {
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
@@ -3145,7 +3145,7 @@ const char *module_address_lookup(unsigned long addr,
strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
ret = namebuf;
}
- preempt_enable();
+ rcu_read_unlock_sched();
return ret;
}
@@ -3153,7 +3153,7 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)
{
struct module *mod;
- preempt_disable();
+ rcu_read_lock_sched();
list_for_each_entry_rcu(mod, &modules, list) {
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
@@ -3163,12 +3163,12 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)
if (!sym)
goto out;
strlcpy(symname, sym, KSYM_NAME_LEN);
- preempt_enable();
+ rcu_read_unlock_sched();
return 0;
}
}
out:
- preempt_enable();
+ rcu_read_unlock_sched();
return -ERANGE;
}
@@ -3177,7 +3177,7 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
{
struct module *mod;
- preempt_disable();
+ rcu_read_lock_sched();
list_for_each_entry_rcu(mod, &modules, list) {
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
@@ -3190,12 +3190,12 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
strlcpy(modname, mod->name, MODULE_NAME_LEN);
if (name)
strlcpy(name, sym, KSYM_NAME_LEN);
- preempt_enable();
+ rcu_read_unlock_sched();
return 0;
}
}
out:
- preempt_enable();
+ rcu_read_unlock_sched();
return -ERANGE;
}
@@ -3204,7 +3204,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
{
struct module *mod;
- preempt_disable();
+ rcu_read_lock_sched();
list_for_each_entry_rcu(mod, &modules, list) {
if (symnum < mod->num_symtab) {
*value = mod->symtab[symnum].st_value;
@@ -3213,12 +3213,12 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
KSYM_NAME_LEN);
strlcpy(module_name, mod->name, MODULE_NAME_LEN);
*exported = is_exported(name, *value, mod);
- preempt_enable();
+ rcu_read_unlock_sched();
return 0;
}
symnum -= mod->num_symtab;
}
- preempt_enable();
+ rcu_read_unlock_sched();
return -ERANGE;
}
@@ -3241,7 +3241,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
unsigned long ret = 0;
/* Don't lock: we're in enough trouble already. */
- preempt_disable();
+ rcu_read_lock_sched();
if ((colon = strchr(name, ':')) != NULL) {
*colon = '\0';
if ((mod = find_module(name)) != NULL)
@@ -3252,7 +3252,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
if ((ret = mod_find_symname(mod, name)) != 0)
break;
}
- preempt_enable();
+ rcu_read_unlock_sched();
return ret;
}
@@ -3379,7 +3379,7 @@ const struct exception_table_entry *search_module_extables(unsigned long addr)
const struct exception_table_entry *e = NULL;
struct module *mod;
- preempt_disable();
+ rcu_read_lock_sched();
list_for_each_entry_rcu(mod, &modules, list) {
if (mod->num_exentries == 0)
continue;
@@ -3390,7 +3390,7 @@ const struct exception_table_entry *search_module_extables(unsigned long addr)
if (e)
break;
}
- preempt_enable();
+ rcu_read_unlock_sched();
/* Now, if we found one, we are running inside it now, hence
we cannot unload the module, hence no refcnt needed. */
@@ -3408,9 +3408,9 @@ bool is_module_address(unsigned long addr)
{
bool ret;
- preempt_disable();
+ rcu_read_lock_sched();
ret = __module_address(addr) != NULL;
- preempt_enable();
+ rcu_read_unlock_sched();
return ret;
}
@@ -3419,7 +3419,7 @@ bool is_module_address(unsigned long addr)
* __module_address - get the module which contains an address.
* @addr: the address.
*
- * Must be called with preempt disabled or module mutex held so that
+ * Must be called with rcu_read_lock_sched or module mutex held so that
* module doesn't get freed during this.
*/
struct module *__module_address(unsigned long addr)
@@ -3449,9 +3449,9 @@ bool is_module_text_address(unsigned long addr)
{
bool ret;
- preempt_disable();
+ rcu_read_lock_sched();
ret = __module_text_address(addr) != NULL;
- preempt_enable();
+ rcu_read_unlock_sched();
return ret;
}
@@ -3460,7 +3460,7 @@ bool is_module_text_address(unsigned long addr)
* __module_text_address - get the module whose code contains an address.
* @addr: the address.
*
- * Must be called with preempt disabled or module mutex held so that
+ * Must be called with rcu_read_lock_sched or module mutex held so that
* module doesn't get freed during this.
*/
struct module *__module_text_address(unsigned long addr)
@@ -3483,11 +3483,11 @@ void print_modules(void)
char buf[8];
printk(KERN_DEFAULT "Modules linked in:");
- /* Most callers should already have preempt disabled, but make sure */
- preempt_disable();
+ /* Most callers should already have rcu_read_lock_sched, but make sure */
+ rcu_read_lock_sched();
list_for_each_entry_rcu(mod, &modules, list)
printk(" %s%s", mod->name, module_flags(mod, buf));
- preempt_enable();
+ rcu_read_unlock_sched();
if (last_unloaded_module[0])
printk(" [last unloaded: %s]", last_unloaded_module);
printk("\n");
--
1.7.7.6
--
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