[tip: x86/cache] cpumask: Relax cpumask_any_but()

[tip-bot2 for Yury Norov [NVIDIA]]

The following commit has been merged into the x86/cache branch of tip:

Commit-ID:     189572bf4e005431051319def435ac4b7e4489ca
Gitweb:        https://git.kernel.org/tip/189572bf4e005431051319def435ac4b7e4489ca
Author:        Yury Norov [NVIDIA] <yury.norov@xxxxxxxxx>
AuthorDate:    Thu, 15 May 2025 16:58:31 
Committer:     Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Thu, 15 May 2025 20:24:22 +02:00

cpumask: Relax cpumask_any_but()

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@xxxxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: James Morse <james.morse@xxxxxxx>
Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Reviewed-by: Fenghua Yu <fenghuay@xxxxxxxxxx>
Tested-by: James Morse <james.morse@xxxxxxx>
Tested-by: Tony Luck <tony.luck@xxxxxxxxx>
Tested-by: Fenghua Yu <fenghuay@xxxxxxxxxx>
Link: https://lore.kernel.org/20250515165855.31452-2-james.morse@xxxxxxx
---
 include/linux/cpumask.h | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index f9a8683..a3ee875 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -413,14 +413,18 @@ 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
-unsigned int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
+unsigned int cpumask_any_but(const struct cpumask *mask, 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;
@@ -433,16 +437,20 @@ 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
 unsigned int cpumask_any_and_but(const struct cpumask *mask1,
 				 const struct cpumask *mask2,
-				 unsigned int cpu)
+				 int cpu)
 {
 	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;