linux-kernel - [PATCH v3 4/6] hwmon: use smp_call_sync_on_phys

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Date:	Fri,  1 Apr 2016 09:14:32 +0200
From:	Juergen Gross <jgross@...e.com>
To:	linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc:	konrad.wilk@...cle.com, boris.ostrovsky@...cle.com,
	david.vrabel@...rix.com, mingo@...hat.com, peterz@...radead.org,
	Douglas_Warzecha@...l.com, pali.rohar@...il.com, jdelvare@...e.com,
	linux@...ck-us.net, tglx@...utronix.de, hpa@...or.com,
	jeremy@...p.org, chrisw@...s-sol.org, akataria@...are.com,
	rusty@...tcorp.com.au, virtualization@...ts.linux-foundation.org,
	x86@...nel.org, Juergen Gross <jgross@...e.com>
Subject: [PATCH v3 4/6] hwmon: use smp_call_sync_on_phys_cpu() for dell-smm i8k

Use the smp_call_sync_on_phys_cpu() function to call system management
mode on cpu 0.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
 drivers/hwmon/dell-smm-hwmon.c | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index c43318d..4875462 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -130,23 +130,15 @@ static inline const char *i8k_get_dmi_data(int field)
 /*
  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
  */
-static int i8k_smm(struct smm_regs *regs)
+static int i8k_smm_func(void *par)
 {
 	int rc;
+	struct smm_regs *regs = par;
 	int eax = regs->eax;
-	cpumask_var_t old_mask;
 
 	/* SMM requires CPU 0 */
-	if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
-		return -ENOMEM;
-	cpumask_copy(old_mask, &current->cpus_allowed);
-	rc = set_cpus_allowed_ptr(current, cpumask_of(0));
-	if (rc)
-		goto out;
-	if (smp_processor_id() != 0) {
-		rc = -EBUSY;
-		goto out;
-	}
+	if (smp_processor_id() != 0)
+		return -EBUSY;
 
 #if defined(CONFIG_X86_64)
 	asm volatile("pushq %%rax\n\t"
@@ -204,13 +196,18 @@ static int i8k_smm(struct smm_regs *regs)
 	if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
 		rc = -EINVAL;
 
-out:
-	set_cpus_allowed_ptr(current, old_mask);
-	free_cpumask_var(old_mask);
 	return rc;
 }
 
 /*
+ * Call the System Management Mode BIOS.
+ */
+static int i8k_smm(struct smm_regs *regs)
+{
+	return smp_call_sync_on_phys_cpu(0, i8k_smm_func, regs);
+}
+
+/*
  * Read the fan status.
  */
 static int i8k_get_fan_status(int fan)
-- 
2.6.2