Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fixes from Thomas Gleixner:
 "This update contains:

   - Fix for a long standing race affecting /proc/irq/NNN

   - One line fix for ARM GICV3-ITS counting the wrong data

   - Warning silencing in ARM GICV3-ITS.  Another GCC trying to be
     overly clever issue"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3-its: Count additional LPIs for the aliased devices
  irqchip/gic-v3-its: Silence warning when its_lpi_alloc_chunks gets inlined
  genirq: Fix race in register_irq_proc()

3 files changed, 21 insertions, 3 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
index cf351c637464..a7c8c9ffbafd 100644
--- a/drivers/irqchip/irq-gic-v3-its-pci-msi.c
+++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
@@ -62,7 +62,7 @@ static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
 
         dev_alias->dev_id = alias;
         if (pdev != dev_alias->pdev)
-                dev_alias->count += its_pci_msi_vec_count(dev_alias->pdev);
+                dev_alias->count += its_pci_msi_vec_count(pdev);
 
         return 0;
 }
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ac7ae2b3cb83..25ceae9f7348 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -719,6 +719,9 @@ static unsigned long *its_lpi_alloc_chunks(int nr_irqs, int *base, int *nr_ids)
 out:
         spin_unlock(&lpi_lock);
 
+        if (!bitmap)
+                *base = *nr_ids = 0;
+
         return bitmap;
 }
 
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index e3a8c9577ba6..a50ddc9417ff 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -12,6 +12,7 @@
 #include <linux/seq_file.h>
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
+#include <linux/mutex.h>
 
 #include "internals.h"
 
@@ -323,18 +324,29 @@ void register_handler_proc(unsigned int irq, struct irqaction *action)
 
 void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 {
+        static DEFINE_MUTEX(register_lock);
         char name [MAX_NAMELEN];
 
-        if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip) || desc->dir)
+        if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
                 return;
 
+        /*
+         * irq directories are registered only when a handler is
+         * added, not when the descriptor is created, so multiple
+         * tasks might try to register at the same time.
+         */
+        mutex_lock(&register_lock);
+
+        if (desc->dir)
+                goto out_unlock;
+
         memset(name, 0, MAX_NAMELEN);
         sprintf(name, "%d", irq);
 
         /* create /proc/irq/1234 */
         desc->dir = proc_mkdir(name, root_irq_dir);
         if (!desc->dir)
-                return;
+                goto out_unlock;
 
 #ifdef CONFIG_SMP
         /* create /proc/irq/<irq>/smp_affinity */
@@ -355,6 +367,9 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 
         proc_create_data("spurious", 0444, desc->dir,
                          &irq_spurious_proc_fops, (void *)(long)irq);
+
+out_unlock:
+        mutex_unlock(&register_lock);
 }
 
 void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)