Revision efba01803c8570bab11d0d6188a630231d0ddccf authored by Michael Chan on 03 December 2008, 08:36:15 UTC, committed by David S. Miller on 03 December 2008, 08:36:15 UTC
The bnx2 chips do not support per MSI vector masking. On 5706/5708, new MSI address/data are stored only when the MSI enable bit is toggled. As a result, SMP affinity no longer works in the latest kernel. A more serious problem is that the driver will no longer receive interrupts when the MSI receiving CPU goes offline. The workaround in this patch only addresses the problem of CPU going offline. When that happens, the driver's timer function will detect that it is making no forward progress on pending interrupt events and will recover from it. Eric Dumazet reported the problem. We also found that if an interrupt is internally asserted while MSI and INTA are disabled, the chip will end up in the same state after MSI is re-enabled. The same workaround is needed for this problem. Signed-off-by: Michael Chan <mchan@broadcom.com> Tested-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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freezer.c
/*
* kernel/freezer.c - Function to freeze a process
*
* Originally from kernel/power/process.c
*/
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/module.h>
#include <linux/syscalls.h>
#include <linux/freezer.h>
/*
* freezing is complete, mark current process as frozen
*/
static inline void frozen_process(void)
{
if (!unlikely(current->flags & PF_NOFREEZE)) {
current->flags |= PF_FROZEN;
wmb();
}
clear_freeze_flag(current);
}
/* Refrigerator is place where frozen processes are stored :-). */
void refrigerator(void)
{
/* Hmm, should we be allowed to suspend when there are realtime
processes around? */
long save;
task_lock(current);
if (freezing(current)) {
frozen_process();
task_unlock(current);
} else {
task_unlock(current);
return;
}
save = current->state;
pr_debug("%s entered refrigerator\n", current->comm);
spin_lock_irq(¤t->sighand->siglock);
recalc_sigpending(); /* We sent fake signal, clean it up */
spin_unlock_irq(¤t->sighand->siglock);
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (!frozen(current))
break;
schedule();
}
pr_debug("%s left refrigerator\n", current->comm);
__set_current_state(save);
}
EXPORT_SYMBOL(refrigerator);
static void fake_signal_wake_up(struct task_struct *p)
{
unsigned long flags;
spin_lock_irqsave(&p->sighand->siglock, flags);
signal_wake_up(p, 0);
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
/**
* freeze_task - send a freeze request to given task
* @p: task to send the request to
* @sig_only: if set, the request will only be sent if the task has the
* PF_FREEZER_NOSIG flag unset
* Return value: 'false', if @sig_only is set and the task has
* PF_FREEZER_NOSIG set or the task is frozen, 'true', otherwise
*
* The freeze request is sent by setting the tasks's TIF_FREEZE flag and
* either sending a fake signal to it or waking it up, depending on whether
* or not it has PF_FREEZER_NOSIG set. If @sig_only is set and the task
* has PF_FREEZER_NOSIG set (ie. it is a typical kernel thread), its
* TIF_FREEZE flag will not be set.
*/
bool freeze_task(struct task_struct *p, bool sig_only)
{
/*
* We first check if the task is freezing and next if it has already
* been frozen to avoid the race with frozen_process() which first marks
* the task as frozen and next clears its TIF_FREEZE.
*/
if (!freezing(p)) {
rmb();
if (frozen(p))
return false;
if (!sig_only || should_send_signal(p))
set_freeze_flag(p);
else
return false;
}
if (should_send_signal(p)) {
if (!signal_pending(p))
fake_signal_wake_up(p);
} else if (sig_only) {
return false;
} else {
wake_up_state(p, TASK_INTERRUPTIBLE);
}
return true;
}
void cancel_freezing(struct task_struct *p)
{
unsigned long flags;
if (freezing(p)) {
pr_debug(" clean up: %s\n", p->comm);
clear_freeze_flag(p);
spin_lock_irqsave(&p->sighand->siglock, flags);
recalc_sigpending_and_wake(p);
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
}
static int __thaw_process(struct task_struct *p)
{
if (frozen(p)) {
p->flags &= ~PF_FROZEN;
return 1;
}
clear_freeze_flag(p);
return 0;
}
/*
* Wake up a frozen process
*
* task_lock() is needed to prevent the race with refrigerator() which may
* occur if the freezing of tasks fails. Namely, without the lock, if the
* freezing of tasks failed, thaw_tasks() might have run before a task in
* refrigerator() could call frozen_process(), in which case the task would be
* frozen and no one would thaw it.
*/
int thaw_process(struct task_struct *p)
{
task_lock(p);
if (__thaw_process(p) == 1) {
task_unlock(p);
wake_up_process(p);
return 1;
}
task_unlock(p);
return 0;
}
EXPORT_SYMBOL(thaw_process);
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