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Merge branch 'urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile into core/urgent

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This commit is contained in:
Ingo Molnar 2009-10-12 23:26:36 +02:00
commit c7cedb125b
1 changed files with 26 additions and 9 deletions
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35
drivers/oprofile/event_buffer.c
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@ -35,12 +35,23 @@ static size_t buffer_pos;
/* atomic_t because wait_event checks it outside of buffer_mutex */ /* atomic_t because wait_event checks it outside of buffer_mutex */
static atomic_t buffer_ready = ATOMIC_INIT(0); static atomic_t buffer_ready = ATOMIC_INIT(0);
/* Add an entry to the event buffer. When we /*
* get near to the end we wake up the process * Add an entry to the event buffer. When we get near to the end we
* sleeping on the read() of the file. * wake up the process sleeping on the read() of the file. To protect
* the event_buffer this function may only be called when buffer_mutex
* is set.
*/ */
void add_event_entry(unsigned long value) void add_event_entry(unsigned long value)
{ {
/*
* This shouldn't happen since all workqueues or handlers are
* canceled or flushed before the event buffer is freed.
*/
if (!event_buffer) {
WARN_ON_ONCE(1);
return;
}
if (buffer_pos == buffer_size) { if (buffer_pos == buffer_size) {
atomic_inc(&oprofile_stats.event_lost_overflow); atomic_inc(&oprofile_stats.event_lost_overflow);
return; return;
@ -69,7 +80,6 @@ void wake_up_buffer_waiter(void)
int alloc_event_buffer(void) int alloc_event_buffer(void)
{ {
int err = -ENOMEM;
unsigned long flags; unsigned long flags;
spin_lock_irqsave(&oprofilefs_lock, flags); spin_lock_irqsave(&oprofilefs_lock, flags);
@ -80,21 +90,22 @@ int alloc_event_buffer(void)
if (buffer_watershed >= buffer_size) if (buffer_watershed >= buffer_size)
return -EINVAL; return -EINVAL;
buffer_pos = 0;
event_buffer = vmalloc(sizeof(unsigned long) * buffer_size); event_buffer = vmalloc(sizeof(unsigned long) * buffer_size);
if (!event_buffer) if (!event_buffer)
goto out; return -ENOMEM;
err = 0; return 0;
out:
return err;
} }
void free_event_buffer(void) void free_event_buffer(void)
{ {
mutex_lock(&buffer_mutex);
vfree(event_buffer); vfree(event_buffer);
buffer_pos = 0;
event_buffer = NULL; event_buffer = NULL;
mutex_unlock(&buffer_mutex);
} }
@ -167,6 +178,12 @@ static ssize_t event_buffer_read(struct file *file, char __user *buf,
mutex_lock(&buffer_mutex); mutex_lock(&buffer_mutex);
/* May happen if the buffer is freed during pending reads. */
if (!event_buffer) {
retval = -EINTR;
goto out;
}
atomic_set(&buffer_ready, 0); atomic_set(&buffer_ready, 0);
retval = -EFAULT; retval = -EFAULT;