diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/kexec.c | 66 | ||||
| -rw-r--r-- | kernel/sched.c | 46 | ||||
| -rw-r--r-- | kernel/sys.c | 2 |
3 files changed, 71 insertions, 43 deletions
diff --git a/kernel/kexec.c b/kernel/kexec.c index c8a4370e2a3..59f3f0df35d 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -12,7 +12,7 @@ #include <linux/slab.h> #include <linux/fs.h> #include <linux/kexec.h> -#include <linux/spinlock.h> +#include <linux/mutex.h> #include <linux/list.h> #include <linux/highmem.h> #include <linux/syscalls.h> @@ -77,7 +77,7 @@ int kexec_should_crash(struct task_struct *p) * * The code for the transition from the current kernel to the * the new kernel is placed in the control_code_buffer, whose size - * is given by KEXEC_CONTROL_CODE_SIZE. In the best case only a single + * is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single * page of memory is necessary, but some architectures require more. * Because this memory must be identity mapped in the transition from * virtual to physical addresses it must live in the range @@ -242,7 +242,7 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry, */ result = -ENOMEM; image->control_code_page = kimage_alloc_control_pages(image, - get_order(KEXEC_CONTROL_CODE_SIZE)); + get_order(KEXEC_CONTROL_PAGE_SIZE)); if (!image->control_code_page) { printk(KERN_ERR "Could not allocate control_code_buffer\n"); goto out; @@ -317,7 +317,7 @@ static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry, */ result = -ENOMEM; image->control_code_page = kimage_alloc_control_pages(image, - get_order(KEXEC_CONTROL_CODE_SIZE)); + get_order(KEXEC_CONTROL_PAGE_SIZE)); if (!image->control_code_page) { printk(KERN_ERR "Could not allocate control_code_buffer\n"); goto out; @@ -924,19 +924,14 @@ static int kimage_load_segment(struct kimage *image, */ struct kimage *kexec_image; struct kimage *kexec_crash_image; -/* - * A home grown binary mutex. - * Nothing can wait so this mutex is safe to use - * in interrupt context :) - */ -static int kexec_lock; + +static DEFINE_MUTEX(kexec_mutex); asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, struct kexec_segment __user *segments, unsigned long flags) { struct kimage **dest_image, *image; - int locked; int result; /* We only trust the superuser with rebooting the system. */ @@ -972,8 +967,7 @@ asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, * * KISS: always take the mutex. */ - locked = xchg(&kexec_lock, 1); - if (locked) + if (!mutex_trylock(&kexec_mutex)) return -EBUSY; dest_image = &kexec_image; @@ -1015,8 +1009,7 @@ asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, image = xchg(dest_image, image); out: - locked = xchg(&kexec_lock, 0); /* Release the mutex */ - BUG_ON(!locked); + mutex_unlock(&kexec_mutex); kimage_free(image); return result; @@ -1063,10 +1056,7 @@ asmlinkage long compat_sys_kexec_load(unsigned long entry, void crash_kexec(struct pt_regs *regs) { - int locked; - - - /* Take the kexec_lock here to prevent sys_kexec_load + /* Take the kexec_mutex here to prevent sys_kexec_load * running on one cpu from replacing the crash kernel * we are using after a panic on a different cpu. * @@ -1074,8 +1064,7 @@ void crash_kexec(struct pt_regs *regs) * of memory the xchg(&kexec_crash_image) would be * sufficient. But since I reuse the memory... */ - locked = xchg(&kexec_lock, 1); - if (!locked) { + if (mutex_trylock(&kexec_mutex)) { if (kexec_crash_image) { struct pt_regs fixed_regs; crash_setup_regs(&fixed_regs, regs); @@ -1083,8 +1072,7 @@ void crash_kexec(struct pt_regs *regs) machine_crash_shutdown(&fixed_regs); machine_kexec(kexec_crash_image); } - locked = xchg(&kexec_lock, 0); - BUG_ON(!locked); + mutex_unlock(&kexec_mutex); } } @@ -1426,25 +1414,23 @@ static int __init crash_save_vmcoreinfo_init(void) module_init(crash_save_vmcoreinfo_init) -/** - * kernel_kexec - reboot the system - * - * Move into place and start executing a preloaded standalone - * executable. If nothing was preloaded return an error. +/* + * Move into place and start executing a preloaded standalone + * executable. If nothing was preloaded return an error. */ int kernel_kexec(void) { int error = 0; - if (xchg(&kexec_lock, 1)) + if (!mutex_trylock(&kexec_mutex)) return -EBUSY; if (!kexec_image) { error = -EINVAL; goto Unlock; } - if (kexec_image->preserve_context) { #ifdef CONFIG_KEXEC_JUMP + if (kexec_image->preserve_context) { mutex_lock(&pm_mutex); pm_prepare_console(); error = freeze_processes(); @@ -1459,6 +1445,7 @@ int kernel_kexec(void) error = disable_nonboot_cpus(); if (error) goto Resume_devices; + device_pm_lock(); local_irq_disable(); /* At this point, device_suspend() has been called, * but *not* device_power_down(). We *must* @@ -1470,26 +1457,22 @@ int kernel_kexec(void) error = device_power_down(PMSG_FREEZE); if (error) goto Enable_irqs; - save_processor_state(); + } else #endif - } else { - blocking_notifier_call_chain(&reboot_notifier_list, - SYS_RESTART, NULL); - system_state = SYSTEM_RESTART; - device_shutdown(); - sysdev_shutdown(); + { + kernel_restart_prepare(NULL); printk(KERN_EMERG "Starting new kernel\n"); machine_shutdown(); } machine_kexec(kexec_image); - if (kexec_image->preserve_context) { #ifdef CONFIG_KEXEC_JUMP - restore_processor_state(); + if (kexec_image->preserve_context) { device_power_up(PMSG_RESTORE); Enable_irqs: local_irq_enable(); + device_pm_unlock(); enable_nonboot_cpus(); Resume_devices: device_resume(PMSG_RESTORE); @@ -1499,11 +1482,10 @@ int kernel_kexec(void) Restore_console: pm_restore_console(); mutex_unlock(&pm_mutex); -#endif } +#endif Unlock: - xchg(&kexec_lock, 0); - + mutex_unlock(&kexec_mutex); return error; } diff --git a/kernel/sched.c b/kernel/sched.c index d601fb0406c..95e6ad3c231 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4669,6 +4669,52 @@ int __sched wait_for_completion_killable(struct completion *x) } EXPORT_SYMBOL(wait_for_completion_killable); +/** + * try_wait_for_completion - try to decrement a completion without blocking + * @x: completion structure + * + * Returns: 0 if a decrement cannot be done without blocking + * 1 if a decrement succeeded. + * + * If a completion is being used as a counting completion, + * attempt to decrement the counter without blocking. This + * enables us to avoid waiting if the resource the completion + * is protecting is not available. + */ +bool try_wait_for_completion(struct completion *x) +{ + int ret = 1; + + spin_lock_irq(&x->wait.lock); + if (!x->done) + ret = 0; + else + x->done--; + spin_unlock_irq(&x->wait.lock); + return ret; +} +EXPORT_SYMBOL(try_wait_for_completion); + +/** + * completion_done - Test to see if a completion has any waiters + * @x: completion structure + * + * Returns: 0 if there are waiters (wait_for_completion() in progress) + * 1 if there are no waiters. + * + */ +bool completion_done(struct completion *x) +{ + int ret = 1; + + spin_lock_irq(&x->wait.lock); + if (!x->done) + ret = 0; + spin_unlock_irq(&x->wait.lock); + return ret; +} +EXPORT_SYMBOL(completion_done); + static long __sched sleep_on_common(wait_queue_head_t *q, int state, long timeout) { diff --git a/kernel/sys.c b/kernel/sys.c index c01858090a9..3dacb00a7f7 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -274,7 +274,7 @@ void emergency_restart(void) } EXPORT_SYMBOL_GPL(emergency_restart); -static void kernel_restart_prepare(char *cmd) +void kernel_restart_prepare(char *cmd) { blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); system_state = SYSTEM_RESTART; |