linux-kernel - [PATCH 03/20] riscv: cleanup send_ipi

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Message-Id: <20190903093239.21278-4-hch@lst.de>
Date:   Tue,  3 Sep 2019 11:32:22 +0200
From:   Christoph Hellwig <hch@....de>
To:     Palmer Dabbelt <palmer@...ive.com>,
        Paul Walmsley <paul.walmsley@...ive.com>
Cc:     Damien Le Moal <damien.lemoal@....com>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Atish Patra <atish.patra@....com>
Subject: [PATCH 03/20] riscv: cleanup send_ipi_mask

Use the special barriers for atomic bitops to make the intention
a little more clear, and use riscv_cpuid_to_hartid_mask instead of
open coding it.

Signed-off-by: Christoph Hellwig <hch@....de>
Reviewed-by: Atish Patra <atish.patra@....com>
---
 arch/riscv/kernel/smp.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 8cd730239613..2e21669aa068 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -80,17 +80,15 @@ static void ipi_stop(void)
 
 static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
 {
-	int cpuid, hartid;
 	struct cpumask hartid_mask;
+	int cpu;
 
-	cpumask_clear(&hartid_mask);
-	mb();
-	for_each_cpu(cpuid, mask) {
-		set_bit(op, &ipi_data[cpuid].bits);
-		hartid = cpuid_to_hartid_map(cpuid);
-		cpumask_set_cpu(hartid, &hartid_mask);
-	}
-	mb();
+	smp_mb__before_atomic();
+	for_each_cpu(cpu, mask)
+		set_bit(op, &ipi_data[cpu].bits);
+	smp_mb__after_atomic();
+
+	riscv_cpuid_to_hartid_mask(mask, &hartid_mask);
 	sbi_send_ipi(cpumask_bits(&hartid_mask));
 }
 
-- 
2.20.1