Messages in this thread Patch in this message | | | Date | Sat, 10 Oct 2009 15:35:57 -0000 | From | Thomas Gleixner <> | Subject | [patch 08/28] x86: Remove BKL from apm_32 |
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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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