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Commit 95ffeb4b authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/irq: Reorganize the search in assign_irq_vector 



Split out the code which advances the target cpu for the search so we can
reuse it for the next patch which adds an early validation check for the
vectormask which we get from the apic.

Add comments while at it.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarBorislav Petkov <bp@alien8.de>
Tested-by: default avatarJoe Lawrence <joe.lawrence@stratus.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jeremiah Mahler <jmmahler@gmail.com>
Cc: andy.shevchenko@gmail.com
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org #4.3+
Link: http://lkml.kernel.org/r/20151231160106.484562040@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 433cbd57

arch/x86/kernel/apic/vector.c

+16 −8
Original line number Diff line number Diff line
@@ -157,14 +157,9 @@ static int __assign_irq_vector(int irq, struct apic_chip_data *d, 
			vector = FIRST_EXTERNAL_VECTOR + offset;

		}



		if (unlikely(current_vector == vector)) {

			cpumask_or(searched_cpumask, searched_cpumask,

				   vector_cpumask);

			cpumask_andnot(vector_cpumask, mask, searched_cpumask);

			cpu = cpumask_first_and(vector_cpumask,

						cpu_online_mask);

			continue;

		}

		/* If the search wrapped around, try the next cpu */

		if (unlikely(current_vector == vector))

			goto next_cpu;



		if (test_bit(vector, used_vectors))

			goto next;
@@ -186,6 +181,19 @@ static int __assign_irq_vector(int irq, struct apic_chip_data *d, 
		d->cfg.vector = vector;

		cpumask_copy(d->domain, vector_cpumask);

		goto success;



next_cpu:

		/*

		 * We exclude the current @vector_cpumask from the requested

		 * @mask and try again with the next online cpu in the

		 * result. We cannot modify @mask, so we use @vector_cpumask

		 * as a temporary buffer here as it will be reassigned when

		 * calling apic->vector_allocation_domain() above.

		 */

		cpumask_or(searched_cpumask, searched_cpumask, vector_cpumask);

		cpumask_andnot(vector_cpumask, mask, searched_cpumask);

		cpu = cpumask_first_and(vector_cpumask, cpu_online_mask);

		continue;

	}

	return -ENOSPC;