2002-02-04 19:57:52

by Bob Miller

Subject: [PATCH] 2.5.3 Can't use spin_lock_* with wait_queue_head_t object.

[PATCH] 2.5.3 Can't use spin_lock_* with wait_queue_head_t object.

There is code in sched.c that uses the spin_lock_* interfaces to acquire and
release the lock in the wait_queue_head_t embedded in the struct completion.

This is wrong and causes the system to OPPs on startup when compiled with
wait.h:USE_RW_WAIT_QUEUE_SPINLOCK set to 1. The patch below changes the
spin_lock_* calls to wq_write_lock_*.


--
Bob Miller Email: [email protected]
Open Software Development Lab Phone: 503.626.2455 Ext. 17


diff -ru linux.2.5.3-orig/include/linux/wait.h linux.2.5.3/include/linux/wait.h
--- linux.2.5.3-orig/include/linux/wait.h Mon Feb 4 11:23:12 2002
+++ linux.2.5.3/include/linux/wait.h Mon Feb 4 11:00:14 2002
@@ -45,6 +45,7 @@
# define wq_read_unlock read_unlock
# define wq_write_lock_irq write_lock_irq
# define wq_write_lock_irqsave write_lock_irqsave
+# define wq_write_unlock_irq write_unlock_irq
# define wq_write_unlock_irqrestore write_unlock_irqrestore
# define wq_write_unlock write_unlock
#else
@@ -57,6 +58,7 @@
# define wq_read_unlock_irqrestore spin_unlock_irqrestore
# define wq_write_lock_irq spin_lock_irq
# define wq_write_lock_irqsave spin_lock_irqsave
+# define wq_write_unlock_irq spin_unlock_irq
# define wq_write_unlock_irqrestore spin_unlock_irqrestore
# define wq_write_unlock spin_unlock
#endif
Only in linux.2.5.3-orig/include/linux: wait.h.orig
diff -ru linux.2.5.3-orig/kernel/sched.c linux.2.5.3/kernel/sched.c
--- linux.2.5.3-orig/kernel/sched.c Mon Jan 28 15:12:47 2002
+++ linux.2.5.3/kernel/sched.c Mon Feb 4 10:42:05 2002
@@ -757,15 +757,15 @@
{
unsigned long flags;

- spin_lock_irqsave(&x->wait.lock, flags);
+ wq_write_lock_irqsave(&x->wait.lock, flags);
x->done++;
__wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, 0);
- spin_unlock_irqrestore(&x->wait.lock, flags);
+ wq_write_unlock_irqrestore(&x->wait.lock, flags);
}

void wait_for_completion(struct completion *x)
{
- spin_lock_irq(&x->wait.lock);
+ wq_write_lock_irq(&x->wait.lock);
if (!x->done) {
DECLARE_WAITQUEUE(wait, current);

@@ -773,14 +773,14 @@
__add_wait_queue_tail(&x->wait, &wait);
do {
__set_current_state(TASK_UNINTERRUPTIBLE);
- spin_unlock_irq(&x->wait.lock);
+ wq_write_unlock_irq(&x->wait.lock);
schedule();
- spin_lock_irq(&x->wait.lock);
+ wq_write_lock_irq(&x->wait.lock);
} while (!x->done);
__remove_wait_queue(&x->wait, &wait);
}
x->done--;
- spin_unlock_irq(&x->wait.lock);
+ wq_write_unlock_irq(&x->wait.lock);
}

#define SLEEP_ON_VAR \