x86/hyperv: Add callback filter to cpumask_to_vpset()

When copying CPUs from a Linux cpumask to a Hyper-V VPset,
cpumask_to_vpset() currently has a "_noself" variant that doesn't copy
the current CPU to the VPset. Generalize this variant by replacing it
with a "_skip" variant having a callback function that is invoked for
each CPU to decide if that CPU should be copied. Update the one caller
of cpumask_to_vpset_noself() to use the new "_skip" variant instead.

No functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1679922967-26582-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

1 files changed, 14 insertions, 8 deletions

diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index afcd9ae9588c..402a8c1c202d 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -210,10 +210,9 @@ static inline int hv_cpu_number_to_vp_number(int cpu_number)
 
 static inline int __cpumask_to_vpset(struct hv_vpset *vpset,
 				    const struct cpumask *cpus,
-				    bool exclude_self)
+				    bool (*func)(int cpu))
 {
 	int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;
-	int this_cpu = smp_processor_id();
 	int max_vcpu_bank = hv_max_vp_index / HV_VCPUS_PER_SPARSE_BANK;
 
 	/* vpset.valid_bank_mask can represent up to HV_MAX_SPARSE_VCPU_BANKS banks */
@@ -232,7 +231,7 @@ static inline int __cpumask_to_vpset(struct hv_vpset *vpset,
 	 * Some banks may end up being empty but this is acceptable.
 	 */
 	for_each_cpu(cpu, cpus) {
-		if (exclude_self && cpu == this_cpu)
+		if (func && func(cpu))
 			continue;
 		vcpu = hv_cpu_number_to_vp_number(cpu);
 		if (vcpu == VP_INVAL)
@@ -248,17 +247,24 @@ static inline int __cpumask_to_vpset(struct hv_vpset *vpset,
 	return nr_bank;
 }
 
+/*
+ * Convert a Linux cpumask into a Hyper-V VPset. In the _skip variant,
+ * 'func' is called for each CPU present in cpumask.  If 'func' returns
+ * true, that CPU is skipped -- i.e., that CPU from cpumask is *not*
+ * added to the Hyper-V VPset. If 'func' is NULL, no CPUs are
+ * skipped.
+ */
 static inline int cpumask_to_vpset(struct hv_vpset *vpset,
 				    const struct cpumask *cpus)
 {
-	return __cpumask_to_vpset(vpset, cpus, false);
+	return __cpumask_to_vpset(vpset, cpus, NULL);
 }
 
-static inline int cpumask_to_vpset_noself(struct hv_vpset *vpset,
-				    const struct cpumask *cpus)
+static inline int cpumask_to_vpset_skip(struct hv_vpset *vpset,
+				    const struct cpumask *cpus,
+				    bool (*func)(int cpu))
 {
-	WARN_ON_ONCE(preemptible());
-	return __cpumask_to_vpset(vpset, cpus, true);
+	return __cpumask_to_vpset(vpset, cpus, func);
 }
 
 void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die);