ACPI: SBS: fix initialization, sem2mutex

cm_sbs_sem is being downed (via acpi_ac_init->acpi_lock_ac_dir) before it is
initialised, with grave results.

- Make it a mutex

- Initialise it

- Make it static

- Clean other stuff up.

Thanks to Paul Drynoff <pauldrynoff@gmail.com> for reporting and testing.

Cc: Rich Townsend <rhdt@bartol.udel.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 14 insertions, 32 deletions

diff --git a/drivers/acpi/cm_sbs.c b/drivers/acpi/cm_sbs.c
index 574a75a166c5..a01ce6700bfe 100644
--- a/drivers/acpi/cm_sbs.c
+++ b/drivers/acpi/cm_sbs.c
@@ -39,50 +39,43 @@ ACPI_MODULE_NAME("cm_sbs")
 static struct proc_dir_entry *acpi_ac_dir;
 static struct proc_dir_entry *acpi_battery_dir;
 
-static struct semaphore cm_sbs_sem;
+static DEFINE_MUTEX(cm_sbs_mutex);
 
-static int lock_ac_dir_cnt = 0;
-static int lock_battery_dir_cnt = 0;
+static int lock_ac_dir_cnt;
+static int lock_battery_dir_cnt;
 
 struct proc_dir_entry *acpi_lock_ac_dir(void)
 {
-
-        down(&cm_sbs_sem);
-        if (!acpi_ac_dir) {
+        mutex_lock(&cm_sbs_mutex);
+        if (!acpi_ac_dir)
                 acpi_ac_dir = proc_mkdir(ACPI_AC_CLASS, acpi_root_dir);
-        }
         if (acpi_ac_dir) {
                 lock_ac_dir_cnt++;
         } else {
                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                   "Cannot create %s\n", ACPI_AC_CLASS));
         }
-        up(&cm_sbs_sem);
+        mutex_unlock(&cm_sbs_mutex);
         return acpi_ac_dir;
 }
-
 EXPORT_SYMBOL(acpi_lock_ac_dir);
 
 void acpi_unlock_ac_dir(struct proc_dir_entry *acpi_ac_dir_param)
 {
-
-        down(&cm_sbs_sem);
-        if (acpi_ac_dir_param) {
+        mutex_lock(&cm_sbs_mutex);
+        if (acpi_ac_dir_param)
                 lock_ac_dir_cnt--;
-        }
         if (lock_ac_dir_cnt == 0 && acpi_ac_dir_param && acpi_ac_dir) {
                 remove_proc_entry(ACPI_AC_CLASS, acpi_root_dir);
                 acpi_ac_dir = 0;
         }
-        up(&cm_sbs_sem);
+        mutex_unlock(&cm_sbs_mutex);
 }
-
 EXPORT_SYMBOL(acpi_unlock_ac_dir);
 
 struct proc_dir_entry *acpi_lock_battery_dir(void)
 {
-
-        down(&cm_sbs_sem);
+        mutex_lock(&cm_sbs_mutex);
         if (!acpi_battery_dir) {
                 acpi_battery_dir =
                     proc_mkdir(ACPI_BATTERY_CLASS, acpi_root_dir);
@@ -93,39 +86,28 @@ struct proc_dir_entry *acpi_lock_battery_dir(void)
                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                   "Cannot create %s\n", ACPI_BATTERY_CLASS));
         }
-        up(&cm_sbs_sem);
+        mutex_unlock(&cm_sbs_mutex);
         return acpi_battery_dir;
 }
-
 EXPORT_SYMBOL(acpi_lock_battery_dir);
 
 void acpi_unlock_battery_dir(struct proc_dir_entry *acpi_battery_dir_param)
 {
-
-        down(&cm_sbs_sem);
-        if (acpi_battery_dir_param) {
+        mutex_lock(&cm_sbs_mutex);
+        if (acpi_battery_dir_param)
                 lock_battery_dir_cnt--;
-        }
         if (lock_battery_dir_cnt == 0 && acpi_battery_dir_param
             && acpi_battery_dir) {
                 remove_proc_entry(ACPI_BATTERY_CLASS, acpi_root_dir);
                 acpi_battery_dir = 0;
         }
-        up(&cm_sbs_sem);
+        mutex_unlock(&cm_sbs_mutex);
         return;
 }
-
 EXPORT_SYMBOL(acpi_unlock_battery_dir);
 
 static int __init acpi_cm_sbs_init(void)
 {
-
-        if (acpi_disabled)
-                return 0;
-
-        init_MUTEX(&cm_sbs_sem);
-
         return 0;
 }
-
 subsys_initcall(acpi_cm_sbs_init);