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Revision eb4400e3a040b90a3ad805b01fcbc99a5f615c8f authored by Maciej Sosnowski on 03 February 2009, 07:26:57 UTC, committed by David S. Miller on 03 February 2009, 07:26:57 UTC 
dca: redesign locks to fix deadlocks
 
Change spin_locks to irqsave to prevent dead-locks.
Protect adding and deleting to/from dca_providers list.
Drop the lock during dca_sysfs_add_req() and dca_sysfs_remove_req() calls
as they might sleep (use GFP_KERNEL allocation).

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent ff01b91
Raw File
smp_processor_id.c 
/*
 * lib/smp_processor_id.c
 *
 * DEBUG_PREEMPT variant of smp_processor_id().
 */
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/sched.h>

notrace unsigned int debug_smp_processor_id(void)
{
	unsigned long preempt_count = preempt_count();
	int this_cpu = raw_smp_processor_id();

	if (likely(preempt_count))
		goto out;

	if (irqs_disabled())
		goto out;

	/*
	 * Kernel threads bound to a single CPU can safely use
	 * smp_processor_id():
	 */
	if (cpus_equal(current->cpus_allowed, cpumask_of_cpu(this_cpu)))
		goto out;

	/*
	 * It is valid to assume CPU-locality during early bootup:
	 */
	if (system_state != SYSTEM_RUNNING)
		goto out;

	/*
	 * Avoid recursion:
	 */
	preempt_disable_notrace();

	if (!printk_ratelimit())
		goto out_enable;

	printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
			"code: %s/%d\n",
			preempt_count() - 1, current->comm, current->pid);
	print_symbol("caller is %s\n", (long)__builtin_return_address(0));
	dump_stack();

out_enable:
	preempt_enable_no_resched_notrace();
out:
	return this_cpu;
}

EXPORT_SYMBOL(debug_smp_processor_id);
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