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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     Chen Zhou <chenzhou10@huawei.com>
Cc:     linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
        chenzhou10@huawei.com, tglx@linutronix.de, mingo@redhat.com
Subject: Re: [PATCH] x86/hyper-v: remove unnecessary conversions to bool
In-Reply-To: <20200110072047.85398-1-chenzhou10@huawei.com>
References: <20200110072047.85398-1-chenzhou10@huawei.com>
Date:   Fri, 10 Jan 2020 12:59:59 +0100
Message-ID: <875zhjr074.fsf@vitty.brq.redhat.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Chen Zhou <chenzhou10@huawei.com> writes:

> The conversions to bool are not needed, remove these.
>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/x86/hyperv/hv_apic.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
> index 40e0e32..3112cf6 100644
> --- a/arch/x86/hyperv/hv_apic.c
> +++ b/arch/x86/hyperv/hv_apic.c
> @@ -133,7 +133,7 @@ static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector)
>  
>  ipi_mask_ex_done:
>  	local_irq_restore(flags);
> -	return ((ret == 0) ? true : false);
> +	return ret == 0;
>  }
>  
>  static bool __send_ipi_mask(const struct cpumask *mask, int vector)
> @@ -186,7 +186,7 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector)
>  
>  	ret = hv_do_fast_hypercall16(HVCALL_SEND_IPI, ipi_arg.vector,
>  				     ipi_arg.cpu_mask);
> -	return ((ret == 0) ? true : false);
> +	return ret == 0;
>  
>  do_ex_hypercall:
>  	return __send_ipi_mask_ex(mask, vector);

I'd suggest we get rid of bool functions completely instead, something
like (untested):

diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index 40e0e322161d..440bda338763 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -97,16 +97,16 @@ static void hv_apic_eoi_write(u32 reg, u32 val)
 /*
  * IPI implementation on Hyper-V.
  */
-static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector)
+static u16 __send_ipi_mask_ex(const struct cpumask *mask, int vector)
 {
 	struct hv_send_ipi_ex **arg;
 	struct hv_send_ipi_ex *ipi_arg;
 	unsigned long flags;
 	int nr_bank = 0;
-	int ret = 1;
+	u16 ret;
 
 	if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
-		return false;
+		return U16_MAX;
 
 	local_irq_save(flags);
 	arg = (struct hv_send_ipi_ex **)this_cpu_ptr(hyperv_pcpu_input_arg);
@@ -129,29 +129,28 @@ static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector)
 		ipi_arg->vp_set.format = HV_GENERIC_SET_ALL;
 
 	ret = hv_do_rep_hypercall(HVCALL_SEND_IPI_EX, 0, nr_bank,
-			      ipi_arg, NULL);
+				  ipi_arg, NULL);
 
 ipi_mask_ex_done:
 	local_irq_restore(flags);
-	return ((ret == 0) ? true : false);
+	return ret;
 }
 
-static bool __send_ipi_mask(const struct cpumask *mask, int vector)
+static u16 __send_ipi_mask(const struct cpumask *mask, int vector)
 {
 	int cur_cpu, vcpu;
 	struct hv_send_ipi ipi_arg;
-	int ret = 1;
 
 	trace_hyperv_send_ipi_mask(mask, vector);
 
 	if (cpumask_empty(mask))
-		return true;
+		return 0;
 
 	if (!hv_hypercall_pg)
-		return false;
+		return U16_MAX;
 
 	if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
-		return false;
+		return U16_MAX;
 
 	/*
 	 * From the supplied CPU set we need to figure out if we can get away
@@ -172,7 +171,7 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector)
 	for_each_cpu(cur_cpu, mask) {
 		vcpu = hv_cpu_number_to_vp_number(cur_cpu);
 		if (vcpu == VP_INVAL)
-			return false;
+			return U16_MAX;
 
 		/*
 		 * This particular version of the IPI hypercall can
@@ -184,41 +183,40 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector)
 		__set_bit(vcpu, (unsigned long *)&ipi_arg.cpu_mask);
 	}
 
-	ret = hv_do_fast_hypercall16(HVCALL_SEND_IPI, ipi_arg.vector,
-				     ipi_arg.cpu_mask);
-	return ((ret == 0) ? true : false);
+	return (u16)hv_do_fast_hypercall16(HVCALL_SEND_IPI, ipi_arg.vector,
+					   ipi_arg.cpu_mask);
 
 do_ex_hypercall:
 	return __send_ipi_mask_ex(mask, vector);
 }
 
-static bool __send_ipi_one(int cpu, int vector)
+static u16 __send_ipi_one(int cpu, int vector)
 {
 	int vp = hv_cpu_number_to_vp_number(cpu);
 
 	trace_hyperv_send_ipi_one(cpu, vector);
 
 	if (!hv_hypercall_pg || (vp == VP_INVAL))
-		return false;
+		return U16_MAX;
 
 	if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
-		return false;
+		return U16_MAX;
 
 	if (vp >= 64)
 		return __send_ipi_mask_ex(cpumask_of(cpu), vector);
 
-	return !hv_do_fast_hypercall16(HVCALL_SEND_IPI, vector, BIT_ULL(vp));
+	return (u16)hv_do_fast_hypercall16(HVCALL_SEND_IPI, vector, BIT_ULL(vp));
 }
 
 static void hv_send_ipi(int cpu, int vector)
 {
-	if (!__send_ipi_one(cpu, vector))
+	if (__send_ipi_one(cpu, vector))
 		orig_apic.send_IPI(cpu, vector);
 }
 
 static void hv_send_ipi_mask(const struct cpumask *mask, int vector)
 {
-	if (!__send_ipi_mask(mask, vector))
+	if (__send_ipi_mask(mask, vector))
 		orig_apic.send_IPI_mask(mask, vector);
 }
 
@@ -231,7 +229,7 @@ static void hv_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
 	cpumask_copy(&new_mask, mask);
 	cpumask_clear_cpu(this_cpu, &new_mask);
 	local_mask = &new_mask;
-	if (!__send_ipi_mask(local_mask, vector))
+	if (__send_ipi_mask(local_mask, vector))
 		orig_apic.send_IPI_mask_allbutself(mask, vector);
 }
 
@@ -242,13 +240,13 @@ static void hv_send_ipi_allbutself(int vector)
 
 static void hv_send_ipi_all(int vector)
 {
-	if (!__send_ipi_mask(cpu_online_mask, vector))
+	if (__send_ipi_mask(cpu_online_mask, vector))
 		orig_apic.send_IPI_all(vector);
 }
 
 static void hv_send_ipi_self(int vector)
 {
-	if (!__send_ipi_one(smp_processor_id(), vector))
+	if (__send_ipi_one(smp_processor_id(), vector))
 		orig_apic.send_IPI_self(vector);
 }

-- 
Vitaly