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Message-ID: <YMaRxsfCOgkc6gjO@yury-ThinkPad>
Date: Sun, 13 Jun 2021 16:16:22 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Yoshinori Sato <ysato@...rs.sourceforge.jp>,
Brian Cain <bcain@...eaurora.org>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
Jonas Bonn <jonas@...thpole.se>,
Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
"James E.J. Bottomley" <James.Bottomley@...senpartnership.com>,
Palmer Dabbelt <palmer@...belt.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Rich Felker <dalias@...c.org>,
David Hildenbrand <david@...hat.com>,
Jaegeuk Kim <jaegeuk@...nel.org>,
Arnd Bergmann <arnd@...db.de>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Andrew Morton <akpm@...ux-foundation.org>,
Alexander Lobakin <alobakin@...me>,
Samuel Mendoza-Jonas <sam@...dozajonas.com>,
Jakub Kicinski <kuba@...nel.org>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Alexey Klimov <aklimov@...hat.com>,
Ingo Molnar <mingo@...hat.com>
Subject: [PATCH] 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@...il.com>
---
I found another ~10 spots where people use find_next_bit() instead
of find_first_bit(). This patch should be added to the series.
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(-)
diff --git a/arch/powerpc/include/asm/cputhreads.h b/arch/powerpc/include/asm/cputhreads.h
index 98c8bd155bf9..fb5bb080e5cd 100644
--- a/arch/powerpc/include/asm/cputhreads.h
+++ b/arch/powerpc/include/asm/cputhreads.h
@@ -52,7 +52,7 @@ static inline cpumask_t cpu_thread_mask_to_cores(const struct cpumask *threads)
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);
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4261adee9964..99644209d693 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2547,7 +2547,7 @@ 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 21ff7b9e49c2..2608e51fe6e9 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2080,7 +2080,7 @@ 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 acda8a5637c5..4d7b9caee1c4 100644
--- 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 96f74a1dc603..e23b60618c1a 100644
--- 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 6bee58600946..7831f406cad2 100644
--- 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 4485635b69f5..61f429fd9c0e 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -256,7 +256,7 @@ 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))
@@ -278,7 +278,7 @@ 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);
}
--
2.30.2
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