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- /*
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- */
- #include <linux/init.h>
- #include <linux/irq.h>
- #include <linux/types.h>
- #include <asm/barrier.h>
- static DECLARE_BITMAP(irq_map, NR_IRQS);
- int allocate_irqno(void)
- {
- int irq;
- again:
- irq = find_first_zero_bit(irq_map, NR_IRQS);
- if (irq >= NR_IRQS)
- return -ENOSPC;
- if (test_and_set_bit(irq, irq_map))
- goto again;
- return irq;
- }
- /*
- * Allocate the 16 legacy interrupts for i8259 devices. This happens early
- * in the kernel initialization so treating allocation failure as BUG() is
- * ok.
- */
- void __init alloc_legacy_irqno(void)
- {
- int i;
- for (i = 0; i <= 16; i++)
- BUG_ON(test_and_set_bit(i, irq_map));
- }
- void free_irqno(unsigned int irq)
- {
- smp_mb__before_atomic();
- clear_bit(irq, irq_map);
- smp_mb__after_atomic();
- }
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