Messages in this thread Patch in this message | | | From | Cong Wang <> | Subject | [V3 PATCH 1/7] module: replace preempt_disable with rcu_read_lock_sched | Date | Thu, 15 Mar 2012 22:48:55 +0800 |
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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@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Reported-by: <Dennis1.Chen@amd.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.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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