Patch "x86/irq: Reorganize the return path in assign_irq_vector" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

x86/irq: Reorganize the return path in assign_irq_vector

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-irq-reorganize-the-return-path-in-assign_irq_vector.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Thomas Gleixner <[email protected]>
Date: Thu, 31 Dec 2015 16:30:46 +0000
Subject: x86/irq: Reorganize the return path in assign_irq_vector

From: Thomas Gleixner <[email protected]>

commit 433cbd57d190a1cdd02f243df41c3d7f55ec4b94 upstream.

Use an explicit goto for the cases where we have success in the search/update and return -ENOSPC if the search loop ends due to no space.

Preparatory patch for fixes. No functional change.

---
 arch/x86/kernel/apic/vector.c |   22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

@@ -116,13 +116,12 @@ static int __assign_irq_vector(int irq,
 	 */
 	static int current_vector = FIRST_EXTERNAL_VECTOR + VECTOR_OFFSET_START;
 	static int current_offset = VECTOR_OFFSET_START % 16;
-	int cpu, err;
+	int cpu;
 
 	if (d->move_in_progress)
 		return -EBUSY;
 
 	/* Only try and allocate irqs on cpus that are present */
-	err = -ENOSPC;
 	cpumask_clear(d->old_domain);
 	cpumask_clear(searched_cpumask);
 	cpu = cpumask_first_and(mask, cpu_online_mask);

@@ -132,9 +131,8 @@ static int __assign_irq_vector(int irq,
 		apic->vector_allocation_domain(cpu, vector_cpumask, mask);
 
 		if (cpumask_subset(vector_cpumask, d->domain)) {
-			err = 0;
 			if (cpumask_equal(vector_cpumask, d->domain))
-				break;
+				goto success;
 			/*
 			 * New cpumask using the vector is a proper subset of
 			 * the current in use mask. So cleanup the vector

@@ -145,7 +143,7 @@ static int __assign_irq_vector(int irq,
 			d->move_in_progress =
 			   cpumask_intersects(d->old_domain, cpu_online_mask);
 			cpumask_and(d->domain, d->domain, vector_cpumask);
-			break;
+			goto success;
 		}
 
 		vector = current_vector;

@@ -185,17 +183,13 @@ next:
 			per_cpu(vector_irq, new_cpu)[vector] = irq_to_desc(irq);
 		d->cfg.vector = vector;
 		cpumask_copy(d->domain, vector_cpumask);
-		err = 0;
-		break;
+		goto success;
 	}
+	return -ENOSPC;
 
-	if (!err) {
-		/* cache destination APIC IDs into cfg->dest_apicid */
-		err = apic->cpu_mask_to_apicid_and(mask, d->domain,
-						   &d->cfg.dest_apicid);
-	}
-
-	return err;
+success:
+	/* cache destination APIC IDs into cfg->dest_apicid */
+	return apic->cpu_mask_to_apicid_and(mask, d->domain, &d->cfg.dest_apicid);
 }
 
 static int assign_irq_vector(int irq, struct apic_chip_data *data,

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/x86-irq-validate-that-irq-descriptor-is-still-active.patch queue-4.4/x86-irq-remove-outgoing-cpu-from-vector-cleanup-mask.patch queue-4.4/x86-irq-get-rid-of-code-duplication.patch queue-4.4/x86-entry-compat-add-missing-clac-to-entry_int80_32.patch queue-4.4/tick-nohz-set-the-correct-expiry-when-switching-to-nohz-lowres-mode.patch queue-4.4/irqchip-mxs-add-missing-set_handle_irq.patch queue-4.4/genirq-validate-action-before-dereferencing-it-in-handle_irq_event_percpu.patch queue-4.4/x86-irq-remove-offline-cpus-from-vector-cleanup.patch queue-4.4/posix-clock-fix-return-code-on-the-poll-method-s-error-path.patch queue-4.4/x86-irq-reorganize-the-return-path-in-assign_irq_vector.patch queue-4.4/cputime-prevent-32bit-overflow-in-time_to_cputime.patch queue-4.4/x86-irq-copy-vectormask-instead-of-an-and-operation.patch queue-4.4/x86-irq-call-irq_force_move_complete-with-irq-descriptor.patch queue-4.4/x86-irq-call-chip-irq_set_affinity-in-proper-context.patch queue-4.4/x86-irq-plug-vector-cleanup-race.patch queue-4.4/x86-irq-do-not-use-apic_chip_data.old_domain-as-temporary-buffer.patch queue-4.4/clockevents-tcb_clksrc-prevent-disabling-an-already-disabled-clock.patch queue-4.4/x86-irq-reorganize-the-search-in-assign_irq_vector.patch queue-4.4/x86-irq-remove-the-cpumask-allocation-from-send_cleanup_vector.patch queue-4.4/x86-irq-fix-a-race-in-x86_vector_free_irqs.patch queue-4.4/x86-irq-check-vector-allocation-early.patch queue-4.4/irqchip-omap-intc-add-support-for-spurious-irq-handling.patch queue-4.4/x86-irq-clear-move_in_progress-before-sending-cleanup-ipi.patch queue-4.4/x86-mpx-fix-off-by-one-comparison-with-nr_registers.patch queue-4.4/irqchip-atmel-aic-fix-wrong-bit-operation-for-irq-priority.patch queue-4.4/revert-workqueue-make-sure-delayed-work-run-in-local-cpu.patch