linux-kernel - [PATCH v5 08/13] LoongArch: KVM: Use concise api _

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Message-Id: <20250701030842.1136519-9-maobibo@loongson.cn>
Date: Tue,  1 Jul 2025 11:08:37 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Tianrui Zhao <zhaotianrui@...ngson.cn>,
	Huacai Chen <chenhuacai@...nel.org>,
	Xianglai Li <lixianglai@...ngson.cn>
Cc: kvm@...r.kernel.org,
	loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH v5 08/13] LoongArch: KVM: Use concise api __ffs()

Function __ffs() is simpler than API find_first_bit() since parameter
data is unsigned long type.

Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
---
 arch/loongarch/kvm/intc/eiointc.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/loongarch/kvm/intc/eiointc.c b/arch/loongarch/kvm/intc/eiointc.c
index 31f2c7476d6f..5b5b3a73a4fb 100644
--- a/arch/loongarch/kvm/intc/eiointc.c
+++ b/arch/loongarch/kvm/intc/eiointc.c
@@ -471,7 +471,7 @@ static int loongarch_eiointc_writeq(struct kvm_vcpu *vcpu,
 				struct loongarch_eiointc *s,
 				gpa_t addr, const void *val)
 {
-	int i, index, irq, bits, ret = 0;
+	int i, index, irq, ret = 0;
 	u8 cpu;
 	u64 data, old_data;
 	gpa_t offset;
@@ -528,12 +528,10 @@ static int loongarch_eiointc_writeq(struct kvm_vcpu *vcpu,
 		/* write 1 to clear interrupt */
 		s->coreisr.reg_u64[cpu][index] = old_data & ~data;
 		data &= old_data;
-		bits = sizeof(data) * 8;
-		irq = find_first_bit((void *)&data, bits);
-		while (irq < bits) {
-			eiointc_update_irq(s, irq + index * bits, 0);
-			bitmap_clear((void *)&data, irq, 1);
-			irq = find_first_bit((void *)&data, bits);
+		while (data) {
+			irq = __ffs(data);
+			eiointc_update_irq(s, irq + index * 64, 0);
+			data &= ~BIT_ULL(irq);
 		}
 		break;
 	case EIOINTC_COREMAP_START ... EIOINTC_COREMAP_END:
-- 
2.39.3