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Subject[patch 16/28] sparc: Remove BKL from apc
commit ab772027 (sparc: arch/sparc/kernel/apc.c to unlocked_ioctl)
added lock/unlock_kernel() to the apc ioctl code.

The code needs no serialization at all. Neither put/get_user nor the
read/write access to the sbus devices require it. Remove BKL.

cycle_kernel_lock() was added during the big BKL pushdown. It should
ensure the serializiation against driver init code. In this case there
is nothing to serialize. Remove it as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David S. Miller <davem@davemloft.net>
---
arch/sparc/kernel/apc.c | 37 ++++++++++---------------------------
1 file changed, 10 insertions(+), 27 deletions(-)

Index: linux-2.6-tip/arch/sparc/kernel/apc.c
===================================================================
--- linux-2.6-tip.orig/arch/sparc/kernel/apc.c
+++ linux-2.6-tip/arch/sparc/kernel/apc.c
@@ -10,7 +10,6 @@
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
-#include <linux/smp_lock.h>
#include <linux/pm.h>
#include <linux/of.h>
#include <linux/of_device.h>
@@ -76,7 +75,6 @@ static inline void apc_free(struct of_de

static int apc_open(struct inode *inode, struct file *f)
{
- cycle_kernel_lock();
return 0;
}

@@ -87,61 +85,46 @@ static int apc_release(struct inode *ino

static long apc_ioctl(struct file *f, unsigned int cmd, unsigned long __arg)
{
- __u8 inarg, __user *arg;
-
- arg = (__u8 __user *) __arg;
-
- lock_kernel();
+ __u8 inarg, __user *arg = (__u8 __user *) __arg;

switch (cmd) {
case APCIOCGFANCTL:
- if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg)) {
- unlock_kernel();
+ if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg))
return -EFAULT;
- }
break;

case APCIOCGCPWR:
- if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg)) {
- unlock_kernel();
+ if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg))
return -EFAULT;
- }
break;

case APCIOCGBPORT:
- if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg)) {
- unlock_kernel();
+ if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg))
return -EFAULT;
- }
break;

case APCIOCSFANCTL:
- if (get_user(inarg, arg)) {
- unlock_kernel();
+ if (get_user(inarg, arg))
return -EFAULT;
- }
apc_writeb(inarg & APC_REGMASK, APC_FANCTL_REG);
break;
+
case APCIOCSCPWR:
- if (get_user(inarg, arg)) {
- unlock_kernel();
+ if (get_user(inarg, arg))
return -EFAULT;
- }
apc_writeb(inarg & APC_REGMASK, APC_CPOWER_REG);
break;
+
case APCIOCSBPORT:
- if (get_user(inarg, arg)) {
- unlock_kernel();
+ if (get_user(inarg, arg))
return -EFAULT;
- }
apc_writeb(inarg & APC_BPMASK, APC_BPORT_REG);
break;
+
default:
- unlock_kernel();
return -EINVAL;
};

- unlock_kernel();
return 0;
}




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