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Subject[PATCH 4.4 330/342] x86/irq: Get rid of code duplication
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

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
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