Patch "x86/irq: Get rid of code duplication" has been added to the 4.4-stable tree

Patch "x86/irq: Get rid of code duplication" has been added to the 4.4-stable tree

[gregkh]

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

    x86/irq: Get rid of code duplication

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-get-rid-of-code-duplication.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 <stable@vger.kernel.org> know about it.


>From ab25ac02148b600e645f77cfb8b8ea415ed75bb4 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 31 Dec 2015 16:30:49 +0000
Subject: x86/irq: Get rid of code duplication

From: Thomas Gleixner <tglx@linutronix.de>

commit ab25ac02148b600e645f77cfb8b8ea415ed75bb4 upstream.

Reusing an existing vector and assigning a new vector has duplicated
code. Consolidate it.

This is also a preparatory patch for finally plugging the cleanup race.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe 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>
Link: http://lkml.kernel.org/r/20151231160106.721599216@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/apic/vector.c |   33 +++++++++++++++------------------
 1 file changed, 15 insertions(+), 18 deletions(-)

--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -116,7 +116,7 @@ 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;
+	int cpu, vector;
 
 	if (d->move_in_progress)
 		return -EBUSY;
@@ -126,7 +126,7 @@ static int __assign_irq_vector(int irq,
 	cpumask_clear(searched_cpumask);
 	cpu = cpumask_first_and(mask, cpu_online_mask);
 	while (cpu < nr_cpu_ids) {
-		int new_cpu, vector, offset;
+		int new_cpu, offset;
 
 		/* Get the possible target cpus for @mask/@cpu from the apic */
 		apic->vector_allocation_domain(cpu, vector_cpumask, mask);
@@ -146,16 +146,12 @@ static int __assign_irq_vector(int irq,
 			if (cpumask_equal(vector_cpumask, d->domain))
 				goto success;
 			/*
-			 * New cpumask using the vector is a proper subset of
-			 * the current in use mask. So cleanup the vector
-			 * allocation for the members that are not used anymore.
+			 * Mark the cpus which are not longer in the mask for
+			 * cleanup.
 			 */
-			cpumask_andnot(d->old_domain, d->domain,
-				       vector_cpumask);
-			d->move_in_progress =
-			   cpumask_intersects(d->old_domain, cpu_online_mask);
-			cpumask_copy(d->domain, vector_cpumask);
-			goto success;
+			cpumask_andnot(d->old_domain, d->domain, vector_cpumask);
+			vector = d->cfg.vector;
+			goto update;
 		}
 
 		vector = current_vector;
@@ -181,16 +177,12 @@ next:
 		/* Found one! */
 		current_vector = vector;
 		current_offset = offset;
-		if (d->cfg.vector) {
+		/* Schedule the old vector for cleanup on all cpus */
+		if (d->cfg.vector)
 			cpumask_copy(d->old_domain, d->domain);
-			d->move_in_progress =
-			   cpumask_intersects(d->old_domain, cpu_online_mask);
-		}
 		for_each_cpu(new_cpu, vector_searchmask)
 			per_cpu(vector_irq, new_cpu)[vector] = irq_to_desc(irq);
-		d->cfg.vector = vector;
-		cpumask_copy(d->domain, vector_cpumask);
-		goto success;
+		goto update;
 
 next_cpu:
 		/*
@@ -207,6 +199,11 @@ next_cpu:
 	}
 	return -ENOSPC;
 
+update:
+	/* Cleanup required ? */
+	d->move_in_progress = cpumask_intersects(d->old_domain, cpu_online_mask);
+	d->cfg.vector = vector;
+	cpumask_copy(d->domain, vector_cpumask);
 success:
 	/*
 	 * Cache destination APIC IDs into cfg->dest_apicid. This cannot fail


Patches currently in stable-queue which might be from tglx@linutronix.de 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