From 6714796edcce27f7a1845e2f79783cd51bb4799b Mon Sep 17 00:00:00 2001
From: Wen Yaxng <wen.yang99@zte.com.cn>
Date: Wed, 8 Nov 2017 09:55:03 +0800
Subject: [PATCH] genirq/proc: Return proper error code when irq_set_affinity()
 fails
Git-commit: 6714796edcce27f7a1845e2f79783cd51bb4799b
Patch-mainline: 4.15-rc1
References: bnc#1105392

write_irq_affinity() returns the number of written bytes, which means
success, unconditionally whether the actual irq_set_affinity() call
succeeded or not.

Add proper error handling and pass the error code returned from
irq_set_affinity() back to user space in case of failure.

[ tglx: Fixed coding style and massaged changelog ]

Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn>
Cc: zhong.weidong@zte.com.cn
Link: https://lkml.kernel.org/r/1510106103-184761-1-git-send-email-wen.yang99@zte.com.cn
Acked-by: Michal Hocko <mhocko@suse.com>

---
 kernel/irq/proc.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -124,8 +124,9 @@ static ssize_t write_irq_affinity(int ty
 		   code to set default SMP affinity. */
 		err = irq_select_affinity_usr(irq, new_value) ? -EINVAL : count;
 	} else {
-		irq_set_affinity(irq, new_value);
-		err = count;
+		err = irq_set_affinity(irq, new_value);
+		if (!err)
+			err = count;
 	}
 
 free_cpumask: