linux-kernel - [PATCH v2 2/3] IRQ,x86: normalize return value of chip->irq_set

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Date:	Fri, 30 Mar 2012 00:44:52 +0800
From:	Jiang Liu <liuj97@...il.com>
To:	Greg KH <greg@...ah.com>, Thomas Gleixner <tglx@...utronix.de>
Cc:	Jiang Liu <jiang.liu@...wei.com>, Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Naga Chumbalkar <nagananda.chumbalkar@...com>,
	Jacob Pan <jacob.jun.pan@...ux.intel.com>,
	Cliff Wickman <cpw@....com>, x86@...nel.org,
	linux-kernel@...r.kernel.org, Jiang Liu <liuj97@...il.com>,
	Keping Chen <chenkeping@...wei.com>
Subject: [PATCH v2 2/3] IRQ,x86: normalize return value of chip->irq_set_affinity() method

On x86 platforms, interrupt controller chip's irq_set_affinity() method
always copies affinity mask to irq_data->affinity field but still returns
0(IRQ_SET_MASK_OK). That return value causes the interrupt core logic
unnecessarily copies the mask to irq_data->affinity field again.
So return IRQ_SET_MASK_OK_NOCOPY instead of IRQ_SET_MASK_OK to get rid of
the duplicated copy operation.

Signed-off-by: Jiang Liu <jiang.liu@...wei.com>
---
 arch/x86/kernel/apic/io_apic.c |   11 ++++++-----
 arch/x86/platform/uv/uv_irq.c  |    2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 6d10a66..092a715 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2346,6 +2346,7 @@ ioapic_set_affinity(struct irq_data *data, const struct cpumask *mask,
 		/* Only the high 8 bits are valid. */
 		dest = SET_APIC_LOGICAL_ID(dest);
 		__target_IO_APIC_irq(irq, dest, data->chip_data);
+		ret = IRQ_SET_MASK_OK_NOCOPY;
 	}
 	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 	return ret;
@@ -2404,7 +2405,7 @@ ir_ioapic_set_affinity(struct irq_data *data, const struct cpumask *mask,
 		send_cleanup_vector(cfg);
 
 	cpumask_copy(data->affinity, mask);
-	return 0;
+	return IRQ_SET_MASK_OK_NOCOPY;
 }
 
 #else
@@ -3209,7 +3210,7 @@ msi_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force)
 
 	__write_msi_msg(data->msi_desc, &msg);
 
-	return 0;
+	return IRQ_SET_MASK_OK_NOCOPY;
 }
 #endif /* CONFIG_SMP */
 
@@ -3366,7 +3367,7 @@ dmar_msi_set_affinity(struct irq_data *data, const struct cpumask *mask,
 
 	dmar_msi_write(irq, &msg);
 
-	return 0;
+	return IRQ_SET_MASK_OK_NOCOPY;
 }
 
 #endif /* CONFIG_SMP */
@@ -3419,7 +3420,7 @@ static int hpet_msi_set_affinity(struct irq_data *data,
 
 	hpet_msi_write(data->handler_data, &msg);
 
-	return 0;
+	return IRQ_SET_MASK_OK_NOCOPY;
 }
 
 #endif /* CONFIG_SMP */
@@ -3499,7 +3500,7 @@ ht_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force)
 		return -1;
 
 	target_ht_irq(data->irq, dest, cfg->vector);
-	return 0;
+	return IRQ_SET_MASK_OK_NOCOPY;
 }
 
 #endif
diff --git a/arch/x86/platform/uv/uv_irq.c b/arch/x86/platform/uv/uv_irq.c
index f25c276..a22c416 100644
--- a/arch/x86/platform/uv/uv_irq.c
+++ b/arch/x86/platform/uv/uv_irq.c
@@ -222,7 +222,7 @@ uv_set_irq_affinity(struct irq_data *data, const struct cpumask *mask,
 	if (cfg->move_in_progress)
 		send_cleanup_vector(cfg);
 
-	return 0;
+	return IRQ_SET_MASK_OK_NOCOPY;
 }
 
 /*
-- 
1.7.5.4

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