From cba4235e6031e9318d68186f6d765c531cbea4e1 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 20 Jun 2017 01:37:21 +0200
Subject: [PATCH] genirq: Remove mask argument from setup_affinity()
Git-commit: cba4235e6031e9318d68186f6d765c531cbea4e1
Patch-mainline: v4.13-rc1
References: bsc#1193231

No point to have this alloc/free dance of cpumasks. Provide a static mask
for setup_affinity() and protect it proper.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235444.851571573@linutronix.de
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 kernel/irq/internals.h |    2 -
 kernel/irq/manage.c    |   53 +++++++++++++++++++++----------------------------
 kernel/irq/proc.c      |    8 ++++---
 3 files changed, 29 insertions(+), 34 deletions(-)

--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -109,7 +109,7 @@ static inline void unregister_handler_pr
 
 extern bool irq_can_set_affinity_usr(unsigned int irq);
 
-extern int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask);
+extern int irq_select_affinity_usr(unsigned int irq);
 
 extern void irq_set_thread_affinity(struct irq_desc *desc);
 
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -345,15 +345,18 @@ EXPORT_SYMBOL_GPL(irq_set_affinity_notif
 /*
  * Generic version of the affinity autoselector.
  */
-static int setup_affinity(struct irq_desc *desc, struct cpumask *mask)
+static int irq_setup_affinity(struct irq_desc *desc)
 {
 	struct cpumask *set = irq_default_affinity;
-	int node = irq_desc_get_node(desc);
+	int ret, node = irq_desc_get_node(desc);
+	static DEFINE_RAW_SPINLOCK(mask_lock);
+	static struct cpumask mask;
 
 	/* Excludes PER_CPU and NO_BALANCE interrupts */
 	if (!__irq_can_set_affinity(desc))
 		return 0;
 
+	raw_spin_lock(&mask_lock);
 	/*
 	 * Preserve the managed affinity setting and a userspace affinity
 	 * setup, but make sure that one of the targets is online.
@@ -367,43 +370,42 @@ static int setup_affinity(struct irq_des
 			irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 	}
 
-	cpumask_and(mask, cpu_online_mask, set);
+	cpumask_and(&mask, cpu_online_mask, set);
 	if (node != NUMA_NO_NODE) {
 		const struct cpumask *nodemask = cpumask_of_node(node);
 
 		/* make sure at least one of the cpus in nodemask is online */
-		if (cpumask_intersects(mask, nodemask))
-			cpumask_and(mask, mask, nodemask);
+		if (cpumask_intersects(&mask, nodemask))
+			cpumask_and(&mask, &mask, nodemask);
 	}
-	irq_do_set_affinity(&desc->irq_data, mask, false);
-	return 0;
+	ret = irq_do_set_affinity(&desc->irq_data, &mask, false);
+	raw_spin_unlock(&mask_lock);
+	return ret;
 }
 #else
 /* Wrapper for ALPHA specific affinity selector magic */
-static inline int setup_affinity(struct irq_desc *d, struct cpumask *mask)
+int irq_setup_affinity(struct irq_desc *desc)
 {
-	return irq_select_affinity(irq_desc_get_irq(d));
+	return irq_select_affinity(irq_desc_get_irq(desc));
 }
 #endif
 
 /*
- * Called when affinity is set via /proc/irq
+ * Called when a bogus affinity is set via /proc/irq
  */
-int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
+int irq_select_affinity_usr(unsigned int irq)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned long flags;
 	int ret;
 
 	raw_spin_lock_irqsave(&desc->lock, flags);
-	ret = setup_affinity(desc, mask);
+	ret = irq_setup_affinity(desc);
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
 	return ret;
 }
-
 #else
-static inline int
-setup_affinity(struct irq_desc *desc, struct cpumask *mask)
+static inline int setup_affinity(struct irq_desc *desc)
 {
 	return 0;
 }
@@ -1128,7 +1130,6 @@ __setup_irq(unsigned int irq, struct irq
 	struct irqaction *old, **old_ptr;
 	unsigned long flags, thread_mask = 0;
 	int ret, nested, shared = 0;
-	cpumask_var_t mask;
 
 	if (!desc)
 		return -EINVAL;
@@ -1187,11 +1188,6 @@ __setup_irq(unsigned int irq, struct irq
 		}
 	}
 
-	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
-		ret = -ENOMEM;
-		goto out_thread;
-	}
-
 	/*
 	 * Drivers are often written to work w/o knowledge about the
 	 * underlying irq chip implementation, so a request for a
@@ -1256,7 +1252,7 @@ __setup_irq(unsigned int irq, struct irq
 		 */
 		if (thread_mask == ~0UL) {
 			ret = -EBUSY;
-			goto out_mask;
+			goto out_unlock;
 		}
 		/*
 		 * The thread_mask for the action is or'ed to
@@ -1300,7 +1296,7 @@ __setup_irq(unsigned int irq, struct irq
 		pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
 		       irq);
 		ret = -EINVAL;
-		goto out_mask;
+		goto out_unlock;
 	}
 
 	if (!shared) {
@@ -1308,7 +1304,7 @@ __setup_irq(unsigned int irq, struct irq
 		if (ret) {
 			pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
 			       new->name, irq, desc->irq_data.chip->name);
-			goto out_mask;
+			goto out_unlock;
 		}
 
 		init_waitqueue_head(&desc->wait_for_threads);
@@ -1320,7 +1316,7 @@ __setup_irq(unsigned int irq, struct irq
 
 			if (ret) {
 				irq_release_resources(desc);
-				goto out_mask;
+				goto out_unlock;
 			}
 		}
 
@@ -1349,7 +1345,7 @@ __setup_irq(unsigned int irq, struct irq
 		}
 
 		/* Set default affinity mask once everything is setup */
-		setup_affinity(desc, mask);
+		irq_setup_affinity(desc);
 
 	} else if (new->flags & IRQF_TRIGGER_MASK) {
 		unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
@@ -1392,8 +1388,6 @@ __setup_irq(unsigned int irq, struct irq
 	register_irq_proc(irq, desc);
 	new->dir = NULL;
 	register_handler_proc(irq, new);
-	free_cpumask_var(mask);
-
 	return 0;
 
 mismatch:
@@ -1406,9 +1400,8 @@ mismatch:
 	}
 	ret = -EBUSY;
 
-out_mask:
+out_unlock:
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
-	free_cpumask_var(mask);
 
 out_thread:
 	if (new->thread) {
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -120,9 +120,11 @@ static ssize_t write_irq_affinity(int ty
 	 * one online CPU still has to be targeted.
 	 */
 	if (!cpumask_intersects(new_value, cpu_online_mask)) {
-		/* Special case for empty set - allow the architecture
-		   code to set default SMP affinity. */
-		err = irq_select_affinity_usr(irq, new_value) ? -EINVAL : count;
+		/*
+		 * Special case for empty set - allow the architecture code
+		 * to set default SMP affinity.
+		 */
+		err = irq_select_affinity_usr(irq) ? -EINVAL : count;
 	} else {
 		irq_set_affinity(irq, new_value);
 		err = count;