genirq: Encapsulate sparse bitmap handling

Move the open coded sparse bitmap handling into helper functions as
a preparatory step for converting the sparse interrupt management
to a maple tree.

No functional change.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230519134902.1495562-3-sdonthineni@nvidia.com

diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 51fc8c4..f3f2090 100644 (file)
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -12,9 +12,9 @@
 #include <linux/sched/clock.h>
 
 #ifdef CONFIG_SPARSE_IRQ
-# define IRQ_BITMAP_BITS       (NR_IRQS + 8196)
+# define MAX_SPARSE_IRQS       (NR_IRQS + 8196)
 #else
-# define IRQ_BITMAP_BITS       NR_IRQS
+# define MAX_SPARSE_IRQS       NR_IRQS
 #endif
 
 #define istate core_internal_state__do_not_mess_with_it

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index b401b89..e0d9dd9 100644 (file)
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -131,7 +131,18 @@ int nr_irqs = NR_IRQS;
 EXPORT_SYMBOL_GPL(nr_irqs);
 
 static DEFINE_MUTEX(sparse_irq_lock);
-static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
+static DECLARE_BITMAP(allocated_irqs, MAX_SPARSE_IRQS);
+
+static int irq_find_free_area(unsigned int from, unsigned int cnt)
+{
+       return bitmap_find_next_zero_area(allocated_irqs, MAX_SPARSE_IRQS,
+                                         from, cnt, 0);
+}
+
+static unsigned int irq_find_at_or_after(unsigned int offset)
+{
+       return find_next_bit(allocated_irqs, nr_irqs, offset);
+}
 
 #ifdef CONFIG_SPARSE_IRQ
 
@@ -517,7 +528,7 @@ err:
 
 static int irq_expand_nr_irqs(unsigned int nr)
 {
-       if (nr > IRQ_BITMAP_BITS)
+       if (nr > MAX_SPARSE_IRQS)
                return -ENOMEM;
        nr_irqs = nr;
        return 0;
@@ -535,11 +546,11 @@ int __init early_irq_init(void)
        printk(KERN_INFO "NR_IRQS: %d, nr_irqs: %d, preallocated irqs: %d\n",
               NR_IRQS, nr_irqs, initcnt);
 
-       if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
-               nr_irqs = IRQ_BITMAP_BITS;
+       if (WARN_ON(nr_irqs > MAX_SPARSE_IRQS))
+               nr_irqs = MAX_SPARSE_IRQS;
 
-       if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
-               initcnt = IRQ_BITMAP_BITS;
+       if (WARN_ON(initcnt > MAX_SPARSE_IRQS))
+               initcnt = MAX_SPARSE_IRQS;
 
        if (initcnt > nr_irqs)
                nr_irqs = initcnt;
@@ -812,8 +823,7 @@ __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
 
        mutex_lock(&sparse_irq_lock);
 
-       start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
-                                          from, cnt, 0);
+       start = irq_find_free_area(from, cnt);
        ret = -EEXIST;
        if (irq >=0 && start != irq)
                goto unlock;
@@ -834,11 +844,11 @@ EXPORT_SYMBOL_GPL(__irq_alloc_descs);
  * irq_get_next_irq - get next allocated irq number
  * @offset:    where to start the search
  *
- * Returns next irq number after offset or nr_irqs if none is found.
+ * Returns next irq number at or after offset or nr_irqs if none is found.
  */
 unsigned int irq_get_next_irq(unsigned int offset)
 {
-       return find_next_bit(allocated_irqs, nr_irqs, offset);
+       return irq_find_at_or_after(offset);
 }
 
 struct irq_desc *