/*
* If the request contains only one semaphore operation, and there are
* no complex transactions pending, lock only the semaphore involved.
* Otherwise, lock the entire semaphore array, since we either have
* multiple semaphores in our own semops, or we need to look at
* semaphores from other pending complex operations.
*
* Carefully guard against sma->complex_count changing between zero
* and non-zero while we are spinning for the lock. The value of
* sma->complex_count cannot change while we are holding the lock,
* so sem_unlock should be fine.
*
* The global lock path checks that all the local locks have been released,
* checking each local lock once. This means that the local lock paths
* cannot start their critical sections while the global lock is held.
*/
static inline int sem_lock(struct sem_array *sma, struct sembuf *sops,
int nsops)
{
int locknum;
again:
if (nsops == 1 && !sma->complex_count) {
struct sem *sem = sma->sem_base + sops->sem_num;
/* Lock just the semaphore we are interested in. */
spin_lock(&sem->lock);
/*
* If sma->complex_count was set while we were spinning,
* we may need to look at things we did not lock here.
*/
if (unlikely(sma->complex_count)) {
spin_unlock(&sem->lock);
goto lock_array;
}
/*
* Another process is holding the global lock on the
* sem_array; we cannot enter our critical section,
* but have to wait for the global lock to be released.
*/
if (unlikely(spin_is_locked(&sma->sem_perm.lock))) {
spin_unlock(&sem->lock);
spin_unlock_wait(&sma->sem_perm.lock);
goto again;
}
locknum = sops->sem_num;
} else {
int i;
/*
* Lock the semaphore array, and wait for all of the
* individual semaphore locks to go away. The code
* above ensures no new single-lock holders will enter
* their critical section while the array lock is held.
*/
lock_array:
spin_lock(&sma->sem_perm.lock);
for (i = 0; i < sma->sem_nsems; i++) {
struct sem *sem = sma->sem_base + i;
spin_unlock_wait(&sem->lock);
}
locknum = -1;
}
return locknum;
}
/* Drop into the prom, with the chance to continue with the 'go'
* prom command.
*/
void
prom_cmdline(void)
{
unsigned long flags;
__save_and_cli(flags);
#ifdef CONFIG_SUN_CONSOLE
if(!serial_console && prom_palette)
prom_palette (1);
#endif
#ifdef CONFIG_SMP
smp_capture();
#endif
p1275_cmd ("enter", P1275_INOUT(0,0));
#ifdef CONFIG_SMP
smp_release();
spin_unlock_wait(&__br_write_locks[BR_GLOBALIRQ_LOCK].lock);
#endif
#ifdef CONFIG_SUN_CONSOLE
if(!serial_console && prom_palette)
prom_palette (0);
#endif
__restore_flags(flags);
}
void dev_deactivate(struct net_device *dev)
{
struct Qdisc *qdisc;
spin_lock_bh(&dev->queue_lock);
qdisc = dev->qdisc;
dev->qdisc = &noop_qdisc;
qdisc_reset(qdisc);
spin_unlock_bh(&dev->queue_lock);
dev_watchdog_down(dev);
while (test_bit(__LINK_STATE_SCHED, &dev->state))
yield();
spin_unlock_wait(&dev->xmit_lock);
}
/* Drop into the prom, with the chance to continue with the 'go'
* prom command.
*/
void
prom_cmdline(void)
{
unsigned long flags;
__save_and_cli(flags);
#ifdef CONFIG_SUN_CONSOLE
if(!serial_console && prom_palette)
prom_palette (1);
#endif
/* We always arrive here via a serial interrupt.
* So in order for everything to work reliably, even
* on SMP, we need to drop the IRQ locks we hold.
*/
#ifdef CONFIG_SMP
irq_exit(smp_processor_id(), 0);
smp_capture();
#else
local_irq_count(smp_processor_id())--;
#endif
p1275_cmd ("enter", P1275_INOUT(0,0));
#ifdef CONFIG_SMP
smp_release();
irq_enter(smp_processor_id(), 0);
spin_unlock_wait(&__br_write_locks[BR_GLOBALIRQ_LOCK].lock);
#else
local_irq_count(smp_processor_id())++;
#endif
#ifdef CONFIG_SUN_CONSOLE
if(!serial_console && prom_palette)
prom_palette (0);
#endif
__restore_flags(flags);
}
static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
{
struct mm_struct * mm, *oldmm;
int retval;
tsk->min_flt = tsk->maj_flt = 0;
tsk->nvcsw = tsk->nivcsw = 0;
tsk->mm = NULL;
tsk->active_mm = NULL;
/*
* Are we cloning a kernel thread?
*
* We need to steal a active VM for that..
*/
oldmm = current->mm;
if (!oldmm)
return 0;
if (clone_flags & CLONE_VM) {
atomic_inc(&oldmm->mm_users);
mm = oldmm;
/*
* There are cases where the PTL is held to ensure no
* new threads start up in user mode using an mm, which
* allows optimizing out ipis; the tlb_gather_mmu code
* is an example.
*/
spin_unlock_wait(&oldmm->page_table_lock);
goto good_mm;
}
retval = -ENOMEM;
mm = allocate_mm();
if (!mm)
goto fail_nomem;
/* Copy the current MM stuff.. */
memcpy(mm, oldmm, sizeof(*mm));
if (!mm_init(mm))
goto fail_nomem;
if (init_new_context(tsk,mm))
goto fail_nocontext;
retval = dup_mmap(mm, oldmm);
if (retval)
goto free_pt;
mm->hiwater_rss = mm->rss;
mm->hiwater_vm = mm->total_vm;
good_mm:
tsk->mm = mm;
tsk->active_mm = mm;
return 0;
free_pt:
mmput(mm);
fail_nomem:
return retval;
fail_nocontext:
/*
* If init_new_context() failed, we cannot use mmput() to free the mm
* because it calls destroy_context()
*/
mm_free_pgd(mm);
free_mm(mm);
return retval;
}
static __inline__ void net_family_read_lock(void)
{
atomic_inc(&net_family_lockct);
spin_unlock_wait(&net_family_lock);
}
static inline void ccids_read_lock(void)
{
atomic_inc(&ccids_lockct);
smp_mb__after_atomic_inc();
spin_unlock_wait(&ccids_lock);
}
