diff options
| -rw-r--r-- | include/linux/kmod.h | 21 | ||||
| -rw-r--r-- | kernel/kmod.c | 47 | ||||
| -rw-r--r-- | kernel/power/process.c | 3 |
3 files changed, 58 insertions, 13 deletions
diff --git a/include/linux/kmod.h b/include/linux/kmod.h index b087377ae2c4..dd99c329e161 100644 --- a/include/linux/kmod.h +++ b/include/linux/kmod.h @@ -110,10 +110,27 @@ call_usermodehelper(char *path, char **argv, char **envp, int wait) extern struct ctl_table usermodehelper_table[]; +enum umh_disable_depth { + UMH_ENABLED = 0, + UMH_FREEZING, + UMH_DISABLED, +}; + extern void usermodehelper_init(void); -extern int usermodehelper_disable(void); -extern void usermodehelper_enable(void); +extern int __usermodehelper_disable(enum umh_disable_depth depth); +extern void __usermodehelper_set_disable_depth(enum umh_disable_depth depth); + +static inline int usermodehelper_disable(void) +{ + return __usermodehelper_disable(UMH_DISABLED); +} + +static inline void usermodehelper_enable(void) +{ + __usermodehelper_set_disable_depth(UMH_ENABLED); +} + extern int usermodehelper_read_trylock(void); extern long usermodehelper_read_lock_wait(long timeout); extern void usermodehelper_read_unlock(void); diff --git a/kernel/kmod.c b/kernel/kmod.c index da7fcca279f9..05698a7415fe 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -322,7 +322,7 @@ static void __call_usermodehelper(struct work_struct *work) * land has been frozen during a system-wide hibernation or suspend operation). * Should always be manipulated under umhelper_sem acquired for write. */ -static int usermodehelper_disabled = 1; +static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED; /* Number of helpers running */ static atomic_t running_helpers = ATOMIC_INIT(0); @@ -347,13 +347,30 @@ static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq); int usermodehelper_read_trylock(void) { + DEFINE_WAIT(wait); int ret = 0; down_read(&umhelper_sem); - if (usermodehelper_disabled) { + for (;;) { + prepare_to_wait(&usermodehelper_disabled_waitq, &wait, + TASK_INTERRUPTIBLE); + if (!usermodehelper_disabled) + break; + + if (usermodehelper_disabled == UMH_DISABLED) + ret = -EAGAIN; + up_read(&umhelper_sem); - ret = -EAGAIN; + + if (ret) + break; + + schedule(); + try_to_freeze(); + + down_read(&umhelper_sem); } + finish_wait(&usermodehelper_disabled_waitq, &wait); return ret; } EXPORT_SYMBOL_GPL(usermodehelper_read_trylock); @@ -392,25 +409,35 @@ void usermodehelper_read_unlock(void) EXPORT_SYMBOL_GPL(usermodehelper_read_unlock); /** - * usermodehelper_enable - allow new helpers to be started again + * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled. + * depth: New value to assign to usermodehelper_disabled. + * + * Change the value of usermodehelper_disabled (under umhelper_sem locked for + * writing) and wakeup tasks waiting for it to change. */ -void usermodehelper_enable(void) +void __usermodehelper_set_disable_depth(enum umh_disable_depth depth) { down_write(&umhelper_sem); - usermodehelper_disabled = 0; + usermodehelper_disabled = depth; wake_up(&usermodehelper_disabled_waitq); up_write(&umhelper_sem); } /** - * usermodehelper_disable - prevent new helpers from being started + * __usermodehelper_disable - Prevent new helpers from being started. + * @depth: New value to assign to usermodehelper_disabled. + * + * Set usermodehelper_disabled to @depth and wait for running helpers to exit. */ -int usermodehelper_disable(void) +int __usermodehelper_disable(enum umh_disable_depth depth) { long retval; + if (!depth) + return -EINVAL; + down_write(&umhelper_sem); - usermodehelper_disabled = 1; + usermodehelper_disabled = depth; up_write(&umhelper_sem); /* @@ -425,7 +452,7 @@ int usermodehelper_disable(void) if (retval) return 0; - usermodehelper_enable(); + __usermodehelper_set_disable_depth(UMH_ENABLED); return -EAGAIN; } diff --git a/kernel/power/process.c b/kernel/power/process.c index 56eaac7e88ab..19db29f67558 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -123,7 +123,7 @@ int freeze_processes(void) { int error; - error = usermodehelper_disable(); + error = __usermodehelper_disable(UMH_FREEZING); if (error) return error; @@ -135,6 +135,7 @@ int freeze_processes(void) error = try_to_freeze_tasks(true); if (!error) { printk("done."); + __usermodehelper_set_disable_depth(UMH_DISABLED); oom_killer_disable(); } printk("\n"); |