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Subject[patch 08/28] x86: Remove BKL from apm_32
The lock/unlock kernel pair in do_open() got there with the BKL push
down and protects nothing. Remove it.

Replace the lock/unlock kernel in the ioctl code with a mutex to
protect standbys_pending and suspends_pending.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/apm_32.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

Index: linux-2.6-tip/arch/x86/kernel/apm_32.c
===================================================================
--- linux-2.6-tip.orig/arch/x86/kernel/apm_32.c
+++ linux-2.6-tip/arch/x86/kernel/apm_32.c
@@ -204,7 +204,6 @@
#include <linux/module.h>

#include <linux/poll.h>
-#include <linux/smp_lock.h>
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/timer.h>
@@ -403,6 +402,7 @@ static DECLARE_WAIT_QUEUE_HEAD(apm_waitq
static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
static struct apm_user *user_list;
static DEFINE_SPINLOCK(user_list_lock);
+static DEFINE_MUTEX(apm_mutex);

/*
* Set up a segment that references the real mode segment 0x40
@@ -1531,7 +1531,7 @@ static long do_ioctl(struct file *filp,
return -EPERM;
switch (cmd) {
case APM_IOC_STANDBY:
- lock_kernel();
+ mutex_lock(&apm_mutex);
if (as->standbys_read > 0) {
as->standbys_read--;
as->standbys_pending--;
@@ -1540,10 +1540,10 @@ static long do_ioctl(struct file *filp,
queue_event(APM_USER_STANDBY, as);
if (standbys_pending <= 0)
standby();
- unlock_kernel();
+ mutex_unlock(&apm_mutex);
break;
case APM_IOC_SUSPEND:
- lock_kernel();
+ mutex_lock(&apm_mutex);
if (as->suspends_read > 0) {
as->suspends_read--;
as->suspends_pending--;
@@ -1552,13 +1552,14 @@ static long do_ioctl(struct file *filp,
queue_event(APM_USER_SUSPEND, as);
if (suspends_pending <= 0) {
ret = suspend(1);
+ mutex_unlock(&apm_mutex);
} else {
as->suspend_wait = 1;
+ mutex_unlock(&apm_mutex);
wait_event_interruptible(apm_suspend_waitqueue,
as->suspend_wait == 0);
ret = as->suspend_result;
}
- unlock_kernel();
return ret;
default:
return -ENOTTY;
@@ -1608,12 +1609,10 @@ static int do_open(struct inode *inode,
{
struct apm_user *as;

- lock_kernel();
as = kmalloc(sizeof(*as), GFP_KERNEL);
if (as == NULL) {
printk(KERN_ERR "apm: cannot allocate struct of size %d bytes\n",
sizeof(*as));
- unlock_kernel();
return -ENOMEM;
}
as->magic = APM_BIOS_MAGIC;
@@ -1635,7 +1634,6 @@ static int do_open(struct inode *inode,
user_list = as;
spin_unlock(&user_list_lock);
filp->private_data = as;
- unlock_kernel();
return 0;
}




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