Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull CPU hotplug updates from Thomas Gleixner:
 "A small update for the SMP hotplug code code:

   - Track "booted once" CPUs in a cpumask so the x86 APIC code has an
     easy way to decide whether broadcast IPIs are safe to use or not.

   - Implement a cpumask_or_equal() helper for the IPI broadcast
     evaluation.

     The above two changes have been also pulled into the x86/apic
     branch for implementing the conditional IPI broadcast feature.

   - Cache the number of online CPUs instead of reevaluating it over and
     over. num_online_cpus() is an unreliable snapshot anyway except
     when it is used outside a cpu hotplug locked region. The cached
     access is not changing this, but it's definitely faster than
     calculating the bitmap wheight especially in hot paths"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Cache number of online CPUs
  cpumask: Implement cpumask_or_equal()
  smp/hotplug: Track booted once CPUs in a cpumask

1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index f58e97446abc..90528f12bdfa 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -120,6 +120,10 @@ extern int __bitmap_empty(const unsigned long *bitmap, unsigned int nbits);
 extern int __bitmap_full(const unsigned long *bitmap, unsigned int nbits);
 extern int __bitmap_equal(const unsigned long *bitmap1,
 			  const unsigned long *bitmap2, unsigned int nbits);
+extern bool __pure __bitmap_or_equal(const unsigned long *src1,
+				     const unsigned long *src2,
+				     const unsigned long *src3,
+				     unsigned int nbits);
 extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
 			unsigned int nbits);
 extern void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
@@ -321,6 +325,25 @@ static inline int bitmap_equal(const unsigned long *src1,
 	return __bitmap_equal(src1, src2, nbits);
 }
 
+/**
+ * bitmap_or_equal - Check whether the or of two bitnaps is equal to a third
+ * @src1:	Pointer to bitmap 1
+ * @src2:	Pointer to bitmap 2 will be or'ed with bitmap 1
+ * @src3:	Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
+ *
+ * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
+ */
+static inline bool bitmap_or_equal(const unsigned long *src1,
+				   const unsigned long *src2,
+				   const unsigned long *src3,
+				   unsigned int nbits)
+{
+	if (!small_const_nbits(nbits))
+		return __bitmap_or_equal(src1, src2, src3, nbits);
+
+	return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
+}
+
 static inline int bitmap_intersects(const unsigned long *src1,
 			const unsigned long *src2, unsigned int nbits)
 {