x86/irq: Get rid of code duplication

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>

diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 641d592f524af6dc70a093485c5658d578d579f1..c604ca651b8a5d22336d58910d77fcf27f62b326 100644 (file)
--- 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, struct apic_chip_data *d,
         */
        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, struct apic_chip_data *d,
        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, struct apic_chip_data *d,
                        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