[115/147] cpumask: replace cpumask_next_* with cpumask_first_* where appropriate

Commit Message

Andrew Morton Sept. 8, 2021, 2:59 a.m. UTC

From: Yury Norov <[e-mail]>
Subject: cpumask: replace cpumask_next_* with cpumask_first_* where appropriate

cpumask_first() is a more effective analogue of 'next' version if n == -1
(which means start == 0).  This patch replaces 'next' with 'first' where
things look trivial.

There's no cpumask_first_zero() function, so create it.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Yury Norov <[e-mail]>
Tested-by: Wolfram Sang <[e-mail]>
Cc: Alexander Lobakin <[e-mail]>
Cc: Alexey Klimov <[e-mail]>
Cc: Andy Shevchenko <[e-mail]>
Cc: Dennis Zhou <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Ulf Hansson <[e-mail]>
Cc: Will Deacon <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 arch/powerpc/include/asm/cputhreads.h |    2 +-
 block/blk-mq.c                        |    2 +-
 drivers/net/virtio_net.c              |    2 +-
 drivers/soc/fsl/qbman/bman_portal.c   |    2 +-
 drivers/soc/fsl/qbman/qman_portal.c   |    2 +-
 include/linux/cpumask.h               |   16 ++++++++++++++++
 kernel/time/clocksource.c             |    4 ++--
 7 files changed, 23 insertions(+), 7 deletions(-)

Patch

--- a/arch/powerpc/include/asm/cputhreads.h~cpumask-replace-cpumask_next_-with-cpumask_first_-where-appropriate
+++ a/arch/powerpc/include/asm/cputhreads.h
@@ -52,7 +52,7 @@  static inline cpumask_t cpu_thread_mask_
 	for (i = 0; i < NR_CPUS; i += threads_per_core) {
 		cpumask_shift_left(&tmp, &threads_core_mask, i);
 		if (cpumask_intersects(threads, &tmp)) {
-			cpu = cpumask_next_and(-1, &tmp, cpu_online_mask);
+			cpu = cpumask_first_and(&tmp, cpu_online_mask);
 			if (cpu < nr_cpu_ids)
 				cpumask_set_cpu(cpu, &res);
 		}
--- a/block/blk-mq.c~cpumask-replace-cpumask_next_-with-cpumask_first_-where-appropriate
+++ a/block/blk-mq.c
@@ -2524,7 +2524,7 @@  static bool blk_mq_hctx_has_requests(str
 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu,
 		struct blk_mq_hw_ctx *hctx)
 {
-	if (cpumask_next_and(-1, hctx->cpumask, cpu_online_mask) != cpu)
+	if (cpumask_first_and(hctx->cpumask, cpu_online_mask) != cpu)
 		return false;
 	if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids)
 		return false;
--- a/drivers/net/virtio_net.c~cpumask-replace-cpumask_next_-with-cpumask_first_-where-appropriate
+++ a/drivers/net/virtio_net.c
@@ -2091,7 +2091,7 @@  static void virtnet_set_affinity(struct
 	stragglers = num_cpu >= vi->curr_queue_pairs ?
 			num_cpu % vi->curr_queue_pairs :
 			0;
-	cpu = cpumask_next(-1, cpu_online_mask);
+	cpu = cpumask_first(cpu_online_mask);
 
 	for (i = 0; i < vi->curr_queue_pairs; i++) {
 		group_size = stride + (i < stragglers ? 1 : 0);
--- a/drivers/soc/fsl/qbman/bman_portal.c~cpumask-replace-cpumask_next_-with-cpumask_first_-where-appropriate
+++ a/drivers/soc/fsl/qbman/bman_portal.c
@@ -155,7 +155,7 @@  static int bman_portal_probe(struct plat
 	}
 
 	spin_lock(&bman_lock);
-	cpu = cpumask_next_zero(-1, &portal_cpus);
+	cpu = cpumask_first_zero(&portal_cpus);
 	if (cpu >= nr_cpu_ids) {
 		__bman_portals_probed = 1;
 		/* unassigned portal, skip init */
--- a/drivers/soc/fsl/qbman/qman_portal.c~cpumask-replace-cpumask_next_-with-cpumask_first_-where-appropriate
+++ a/drivers/soc/fsl/qbman/qman_portal.c
@@ -248,7 +248,7 @@  static int qman_portal_probe(struct plat
 	pcfg->pools = qm_get_pools_sdqcr();
 
 	spin_lock(&qman_lock);
-	cpu = cpumask_next_zero(-1, &portal_cpus);
+	cpu = cpumask_first_zero(&portal_cpus);
 	if (cpu >= nr_cpu_ids) {
 		__qman_portals_probed = 1;
 		/* unassigned portal, skip init */
--- a/include/linux/cpumask.h~cpumask-replace-cpumask_next_-with-cpumask_first_-where-appropriate
+++ a/include/linux/cpumask.h
@@ -123,6 +123,11 @@  static inline unsigned int cpumask_first
 	return 0;
 }
 
+static inline unsigned int cpumask_first_zero(const struct cpumask *srcp)
+{
+	return 0;
+}
+
 static inline unsigned int cpumask_first_and(const struct cpumask *srcp1,
 					     const struct cpumask *srcp2)
 {
@@ -202,6 +207,17 @@  static inline unsigned int cpumask_first
 }
 
 /**
+ * cpumask_first_zero - get the first unset cpu in a cpumask
+ * @srcp: the cpumask pointer
+ *
+ * Returns >= nr_cpu_ids if all cpus are set.
+ */
+static inline unsigned int cpumask_first_zero(const struct cpumask *srcp)
+{
+	return find_first_zero_bit(cpumask_bits(srcp), nr_cpumask_bits);
+}
+
+/**
  * cpumask_first_and - return the first cpu from *srcp1 & *srcp2
  * @src1p: the first input
  * @src2p: the second input
--- a/kernel/time/clocksource.c~cpumask-replace-cpumask_next_-with-cpumask_first_-where-appropriate
+++ a/kernel/time/clocksource.c
@@ -257,7 +257,7 @@  static void clocksource_verify_choose_cp
 		return;
 
 	/* Make sure to select at least one CPU other than the current CPU. */
-	cpu = cpumask_next(-1, cpu_online_mask);
+	cpu = cpumask_first(cpu_online_mask);
 	if (cpu == smp_processor_id())
 		cpu = cpumask_next(cpu, cpu_online_mask);
 	if (WARN_ON_ONCE(cpu >= nr_cpu_ids))
@@ -279,7 +279,7 @@  static void clocksource_verify_choose_cp
 		cpu = prandom_u32() % nr_cpu_ids;
 		cpu = cpumask_next(cpu - 1, cpu_online_mask);
 		if (cpu >= nr_cpu_ids)
-			cpu = cpumask_next(-1, cpu_online_mask);
+			cpu = cpumask_first(cpu_online_mask);
 		if (!WARN_ON_ONCE(cpu >= nr_cpu_ids))
 			cpumask_set_cpu(cpu, &cpus_chosen);
 	}