[PATCH 1/4] cpumask: relax cpumask_any_but()

Yury Norov
2025-04-07T15:39:01Z

From: Yury Norov [NVIDIA] <yury.norov@gmail.com>

Similarly to other cpumask search functions, accept -1, and consider
it as 'any cpu' hint. This helps users to avoid coding special cases.

Signed-off-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
---
include/linux/cpumask.h | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index beff4d26e605..0f816092c891 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -413,6 +413,7 @@ unsigned int cpumask_next_wrap(int n, const struct cpumask *src)
* @cpu: the cpu to ignore.
*
* Often used to find any cpu but smp_processor_id() in a mask.
+ * If @cpu == -1, the function is equivalent to cpumask_any().
* Return: >= nr_cpu_ids if no cpus set.
*/
static __always_inline
@@ -420,7 +421,10 @@ unsigned int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
{
unsigned int i;

- cpumask_check(cpu);
+ /* -1 is a legal arg here. */
+ if (cpu != -1)
+ cpumask_check(cpu);
+
for_each_cpu(i, mask)
if (i != cpu)
break;
@@ -433,6 +437,7 @@ unsigned int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
* @mask2: the second input cpumask
* @cpu: the cpu to ignore
*
+ * If @cpu == -1, the function is equivalent to cpumask_any_and().
* Returns >= nr_cpu_ids if no cpus set.
*/
static __always_inline
@@ -442,7 +447,10 @@ unsigned int cpumask_any_and_but(const struct cpumask *mask1,
{
unsigned int i;

- cpumask_check(cpu);
+ /* -1 is a legal arg here. */
+ if (cpu != -1)
+ cpumask_check(cpu);
+
i = cpumask_first_and(mask1, mask2);
if (i != cpu)
return i;
--
2.43.0