Merge tag 'bitmap-6.1-rc1' of https://github.com/norov/linux

Pull bitmap updates from Yury Norov:

 - Fix unsigned comparison to -1 in CPUMAP_FILE_MAX_BYTES (Phil Auld)

 - cleanup nr_cpu_ids vs nr_cpumask_bits mess (me)

   This series cleans that mess and adds new config FORCE_NR_CPUS that
   allows to optimize cpumask subsystem if the number of CPUs is known
   at compile-time.

 - optimize find_bit() functions (me)

   Reworks find_bit() functions based on new FIND_{FIRST,NEXT}_BIT()
   macros.

 - add find_nth_bit() (me)

   Adds find_nth_bit(), which is ~70 times faster than bitcounting with
   for_each() loop:

	for_each_set_bit(bit, mask, size)
		if (n-- == 0)
			return bit;

   Also adds bitmap_weight_and() to let people replace this pattern:

	tmp = bitmap_alloc(nbits);
	bitmap_and(tmp, map1, map2, nbits);
	weight = bitmap_weight(tmp, nbits);
	bitmap_free(tmp);

   with a single bitmap_weight_and() call.

 - repair cpumask_check() (me)

   After switching cpumask to use nr_cpu_ids, cpumask_check() started
   generating many false-positive warnings. This series fixes it.

 - Add for_each_cpu_andnot() and for_each_cpu_andnot() (Valentin
   Schneider)

   Extends the API with one more function and applies it in sched/core.

* tag 'bitmap-6.1-rc1' of https://github.com/norov/linux: (28 commits)
  sched/core: Merge cpumask_andnot()+for_each_cpu() into for_each_cpu_andnot()
  lib/test_cpumask: Add for_each_cpu_and(not) tests
  cpumask: Introduce for_each_cpu_andnot()
  lib/find_bit: Introduce find_next_andnot_bit()
  cpumask: fix checking valid cpu range
  lib/bitmap: add tests for for_each() loops
  lib/find: optimize for_each() macros
  lib/bitmap: introduce for_each_set_bit_wrap() macro
  lib/find_bit: add find_next{,_and}_bit_wrap
  cpumask: switch for_each_cpu{,_not} to use for_each_bit()
  net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and}
  cpumask: add cpumask_nth_{,and,andnot}
  lib/bitmap: remove bitmap_ord_to_pos
  lib/bitmap: add tests for find_nth_bit()
  lib: add find_nth{,_and,_andnot}_bit()
  lib/bitmap: add bitmap_weight_and()
  lib/bitmap: don't call __bitmap_weight() in kernel code
  tools: sync find_bit() implementation
  lib/find_bit: optimize find_next_bit() functions
  lib/find_bit: create find_first_zero_bit_le()
  ...

2 files changed, 5 insertions, 6 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 8cd1b5a8f613..f4d02201f424 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -357,10 +357,7 @@ static void __sched_core_flip(bool enabled)
 	/*
 	 * Toggle the offline CPUs.
 	 */
-	cpumask_copy(&sched_core_mask, cpu_possible_mask);
-	cpumask_andnot(&sched_core_mask, &sched_core_mask, cpu_online_mask);
-
-	for_each_cpu(cpu, &sched_core_mask)
+	for_each_cpu_andnot(cpu, cpu_possible_mask, cpu_online_mask)
 		cpu_rq(cpu)->core_enabled = enabled;
 
 	cpus_read_unlock();
diff --git a/kernel/smp.c b/kernel/smp.c
index e8cdc025a046..06a413987a14 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -1069,7 +1069,7 @@ static int __init nrcpus(char *str)
 	int nr_cpus;
 
 	if (get_option(&str, &nr_cpus) && nr_cpus > 0 && nr_cpus < nr_cpu_ids)
-		nr_cpu_ids = nr_cpus;
+		set_nr_cpu_ids(nr_cpus);
 
 	return 0;
 }
@@ -1087,14 +1087,16 @@ static int __init maxcpus(char *str)
 
 early_param("maxcpus", maxcpus);
 
+#if (NR_CPUS > 1) && !defined(CONFIG_FORCE_NR_CPUS)
 /* Setup number of possible processor ids */
 unsigned int nr_cpu_ids __read_mostly = NR_CPUS;
 EXPORT_SYMBOL(nr_cpu_ids);
+#endif
 
 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
 void __init setup_nr_cpu_ids(void)
 {
-	nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
+	set_nr_cpu_ids(find_last_bit(cpumask_bits(cpu_possible_mask), NR_CPUS) + 1);
 }
 
 /* Called by boot processor to activate the rest. */