genirq: Expose nr_irqs in core code

... to avoid function calls in the core code to retrieve the maximum number
of interrupts.

Rename it to 'total_nr_irqs' as 'nr_irqs' is too generic and fix up the
'nr_irqs' reference in the related GDB script as well.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://patch.msgid.link/20260517194931.522168332@kernel.org

4 files changed, 18 insertions, 17 deletions

diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 9412e57056f5..db359acdf27f 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -21,6 +21,7 @@
 
 extern bool noirqdebug;
 extern int irq_poll_cpu;
+extern unsigned int total_nr_irqs;
 
 extern struct irqaction chained_action;
 
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 7173b8b634f2..a7ce1e8165a6 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -140,14 +140,14 @@ static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
 	desc_smp_init(desc, node, affinity);
 }
 
-static unsigned int nr_irqs = NR_IRQS;
+unsigned int total_nr_irqs __read_mostly = NR_IRQS;
 
 /**
  * irq_get_nr_irqs() - Number of interrupts supported by the system.
  */
 unsigned int irq_get_nr_irqs(void)
 {
-	return nr_irqs;
+	return total_nr_irqs;
 }
 EXPORT_SYMBOL_GPL(irq_get_nr_irqs);
 
@@ -159,7 +159,7 @@ EXPORT_SYMBOL_GPL(irq_get_nr_irqs);
  */
 unsigned int irq_set_nr_irqs(unsigned int nr)
 {
-	nr_irqs = nr;
+	total_nr_irqs = nr;
 
 	return nr;
 }
@@ -187,9 +187,9 @@ static unsigned int irq_find_at_or_after(unsigned int offset)
 	struct irq_desc *desc;
 
 	guard(rcu)();
-	desc = mt_find(&sparse_irqs, &index, nr_irqs);
+	desc = mt_find(&sparse_irqs, &index, total_nr_irqs);
 
-	return desc ? irq_desc_get_irq(desc) : nr_irqs;
+	return desc ? irq_desc_get_irq(desc) : total_nr_irqs;
 }
 
 static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
@@ -543,7 +543,7 @@ static bool irq_expand_nr_irqs(unsigned int nr)
 {
 	if (nr > MAX_SPARSE_IRQS)
 		return false;
-	nr_irqs = nr;
+	total_nr_irqs = nr;
 	return true;
 }
 
@@ -557,16 +557,16 @@ int __init early_irq_init(void)
 	/* Let arch update nr_irqs and return the nr of preallocated irqs */
 	initcnt = arch_probe_nr_irqs();
 	printk(KERN_INFO "NR_IRQS: %d, nr_irqs: %d, preallocated irqs: %d\n",
-	       NR_IRQS, nr_irqs, initcnt);
+	       NR_IRQS, total_nr_irqs, initcnt);
 
-	if (WARN_ON(nr_irqs > MAX_SPARSE_IRQS))
-		nr_irqs = MAX_SPARSE_IRQS;
+	if (WARN_ON(total_nr_irqs > MAX_SPARSE_IRQS))
+		total_nr_irqs = MAX_SPARSE_IRQS;
 
 	if (WARN_ON(initcnt > MAX_SPARSE_IRQS))
 		initcnt = MAX_SPARSE_IRQS;
 
-	if (initcnt > nr_irqs)
-		nr_irqs = initcnt;
+	if (initcnt > total_nr_irqs)
+		total_nr_irqs = initcnt;
 
 	for (i = 0; i < initcnt; i++) {
 		desc = alloc_desc(i, node, 0, NULL, NULL);
@@ -862,7 +862,7 @@ void irq_free_descs(unsigned int from, unsigned int cnt)
 {
 	int i;
 
-	if (from >= nr_irqs || (from + cnt) > nr_irqs)
+	if (from >= total_nr_irqs || (from + cnt) > total_nr_irqs)
 		return;
 
 	guard(mutex)(&sparse_irq_lock);
@@ -911,7 +911,7 @@ int __ref __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int no
 	if (irq >=0 && start != irq)
 		return -EEXIST;
 
-	if (start + cnt > nr_irqs) {
+	if (start + cnt > total_nr_irqs) {
 		if (!irq_expand_nr_irqs(start + cnt))
 			return -ENOMEM;
 	}
@@ -923,7 +923,7 @@ 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 after offset or total_nr_irqs if none is found.
  */
 unsigned int irq_get_next_irq(unsigned int offset)
 {
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 5a1805b0b8a9..d5b812680f5c 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -448,7 +448,7 @@ int __weak arch_show_interrupts(struct seq_file *p, int prec)
 }
 
 #ifndef ACTUAL_NR_IRQS
-# define ACTUAL_NR_IRQS irq_get_nr_irqs()
+# define ACTUAL_NR_IRQS total_nr_irqs
 #endif
 
 /* Same as seq_put_decimal_ull_width(p, " ", cnt, 10) */
@@ -490,7 +490,7 @@ void irq_proc_emit_counts(struct seq_file *p, unsigned int __percpu *cnts)
 
 int show_interrupts(struct seq_file *p, void *v)
 {
-	const unsigned int nr_irqs = irq_get_nr_irqs();
+	const unsigned int nr_irqs = total_nr_irqs;
 	static int prec;
 
 	int i = *(loff_t *) v, j;
diff --git a/scripts/gdb/linux/interrupts.py b/scripts/gdb/linux/interrupts.py
index b794e013c360..a4e25d2bf123 100644
--- a/scripts/gdb/linux/interrupts.py
+++ b/scripts/gdb/linux/interrupts.py
@@ -174,7 +174,7 @@ class LxInterruptList(gdb.Command):
         super(LxInterruptList, self).__init__("lx-interruptlist", gdb.COMMAND_DATA)
 
     def invoke(self, arg, from_tty):
-        nr_irqs = gdb.parse_and_eval("nr_irqs")
+        nr_irqs = gdb.parse_and_eval("total_nr_irqs")
         prec = 3
         j = 1000
         while prec < 10 and j <= nr_irqs: