cpumask: add cpumask_weight_andnot()

Similarly to cpumask_weight_and(), cpumask_weight_andnot() is a handy
helper that may help to avoid creating an intermediate mask just to
calculate number of bits that set in a 1st given mask, and clear in 2nd
one.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index cfb545841a2c..228c23eb36d2 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -720,6 +720,19 @@ static inline unsigned int cpumask_weight_and(const struct cpumask *srcp1,
 }
 
 /**
+ * cpumask_weight_andnot - Count of bits in (*srcp1 & ~*srcp2)
+ * @srcp1: the cpumask to count bits (< nr_cpu_ids) in.
+ * @srcp2: the cpumask to count bits (< nr_cpu_ids) in.
+ *
+ * Return: count of bits set in both *srcp1 and *srcp2
+ */
+static inline unsigned int cpumask_weight_andnot(const struct cpumask *srcp1,
+						const struct cpumask *srcp2)
+{
+	return bitmap_weight_andnot(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
+}
+
+/**
  * cpumask_shift_right - *dstp = *srcp >> n
  * @dstp: the cpumask result
  * @srcp: the input to shift