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.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8874a63..ef56e75 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2967,7 +2967,7 @@ static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
 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;

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b107835..8c70ab3 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2101,7 +2101,7 @@ static void virtnet_set_affinity(struct virtnet_info *vi)
        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);

diff --git a/drivers/soc/fsl/qbman/bman_portal.c b/drivers/soc/fsl/qbman/bman_portal.c
index acda8a5..4d7b9ca 100644 (file)
--- a/drivers/soc/fsl/qbman/bman_portal.c
+++ b/drivers/soc/fsl/qbman/bman_portal.c
@@ -155,7 +155,7 @@ static int bman_portal_probe(struct platform_device *pdev)
        }
 
        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 */

diff --git a/drivers/soc/fsl/qbman/qman_portal.c b/drivers/soc/fsl/qbman/qman_portal.c
index 96f74a1..e23b606 100644 (file)
--- a/drivers/soc/fsl/qbman/qman_portal.c
+++ b/drivers/soc/fsl/qbman/qman_portal.c
@@ -248,7 +248,7 @@ static int qman_portal_probe(struct platform_device *pdev)
        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 */

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index c4e1b9e..64dae70 100644 (file)
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -123,6 +123,11 @@ static inline unsigned int cpumask_first(const struct cpumask *srcp)
        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)
 {
@@ -201,6 +206,17 @@ static inline unsigned int cpumask_first(const struct cpumask *srcp)
        return find_first_bit(cpumask_bits(srcp), nr_cpumask_bits);
 }
 
+/**
+ * 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

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index b8a14d2..f29d1a5 100644 (file)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -257,7 +257,7 @@ static void clocksource_verify_choose_cpus(void)
                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_cpus(void)
                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);
        }