Re: [patch V6 08/16] genirq: Expose nr_irqs in core code

[Shrikanth Hegde <sshegde@linux.ibm.com>]

On 5/18/26 1:32 AM, Thomas Gleixner wrote:
> From: Thomas Gleixner <tglx@kernel.org>
> 
> ... 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>
> ---
> V3: Fix up the missing usage sites and gdb script - Radu
> ---
>   kernel/irq/internals.h          |    1 +
>   kernel/irq/irqdesc.c            |   28 ++++++++++++++--------------
>   kernel/irq/proc.c               |    4 ++--
>   scripts/gdb/linux/interrupts.py |    2 +-
>   4 files changed, 18 insertions(+), 17 deletions(-)
> --- 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;
>   
> --- a/kernel/irq/irqdesc.c
> +++ b/kernel/irq/irqdesc.c
> @@ -140,14 +140,14 @@ static void desc_set_defaults(unsigned i
>   	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
>   	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
>   {
>   	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, u
>   {
>   	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, uns
>   	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)
>   {
> --- a/kernel/irq/proc.c
> +++ b/kernel/irq/proc.c
> @@ -447,7 +447,7 @@ int __weak arch_show_interrupts(struct s
>   }
>   
>   #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) */
> @@ -489,7 +489,7 @@ void irq_proc_emit_counts(struct seq_fil
>   
>   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;
> --- a/scripts/gdb/linux/interrupts.py
> +++ b/scripts/gdb/linux/interrupts.py
> @@ -174,7 +174,7 @@ irq_desc_type = utils.CachedType("struct
>           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:
> 

nr_irqs was used as arg in some of those irq_chip methods.
This can help avoid any such confusion.

Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>