PM: wakelocks: Use seq_file for /proc/wakelocks so we can get more than 3K of stats.
Arve Hjønnevåg [Thu, 3 Dec 2009 02:22:00 +0000 (18:22 -0800)]
Change-Id: I42ed8bea639684f7a8a95b2057516764075c6b01
Signed-off-by: Arve Hjønnevåg <arve@android.com>

kernel/power/wakelock.c

index 263de24..4b0e260 100644 (file)
@@ -40,8 +40,6 @@ module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);
 #define WAKE_LOCK_AUTO_EXPIRE            (1U << 10)
 #define WAKE_LOCK_PREVENTING_SUSPEND     (1U << 11)
 
-#define TOO_MAY_LOCKS_WARNING          "\n\ntoo many wakelocks!!!\n"
-
 static DEFINE_SPINLOCK(list_lock);
 static LIST_HEAD(inactive_locks);
 static struct list_head active_wake_locks[WAKE_LOCK_TYPE_COUNT];
@@ -83,14 +81,13 @@ int get_expired_time(struct wake_lock *lock, ktime_t *expire_time)
 }
 
 
-static int print_lock_stat(char *buf, int len, struct wake_lock *lock)
+static int print_lock_stat(struct seq_file *m, struct wake_lock *lock)
 {
        int lock_count = lock->stat.count;
        int expire_count = lock->stat.expire_count;
        ktime_t active_time = ktime_set(0, 0);
        ktime_t total_time = lock->stat.total_time;
        ktime_t max_time = lock->stat.max_time;
-       int n;
 
        ktime_t prevent_suspend_time = lock->stat.prevent_suspend_time;
        if (lock->flags & WAKE_LOCK_ACTIVE) {
@@ -112,48 +109,34 @@ static int print_lock_stat(char *buf, int len, struct wake_lock *lock)
                        max_time = add_time;
        }
 
-       n = snprintf(buf, len,
+       return seq_printf(m,
                     "\"%s\"\t%d\t%d\t%d\t%lld\t%lld\t%lld\t%lld\t%lld\n",
                     lock->name, lock_count, expire_count,
                     lock->stat.wakeup_count, ktime_to_ns(active_time),
                     ktime_to_ns(total_time),
                     ktime_to_ns(prevent_suspend_time), ktime_to_ns(max_time),
                     ktime_to_ns(lock->stat.last_time));
-
-       return n > len ? len : n;
 }
 
-
-static int wakelocks_read_proc(char *page, char **start, off_t off,
-                              int count, int *eof, void *data)
+static int wakelock_stats_show(struct seq_file *m, void *unused)
 {
        unsigned long irqflags;
        struct wake_lock *lock;
-       int len = 0;
+       int ret;
        int type;
 
        spin_lock_irqsave(&list_lock, irqflags);
 
-       len += snprintf(page + len, count - len,
-                       "name\tcount\texpire_count\twake_count\tactive_since"
+       ret = seq_puts(m, "name\tcount\texpire_count\twake_count\tactive_since"
                        "\ttotal_time\tsleep_time\tmax_time\tlast_change\n");
-       list_for_each_entry(lock, &inactive_locks, link) {
-               len += print_lock_stat(page + len, count - len, lock);
-       }
+       list_for_each_entry(lock, &inactive_locks, link)
+               ret = print_lock_stat(m, lock);
        for (type = 0; type < WAKE_LOCK_TYPE_COUNT; type++) {
                list_for_each_entry(lock, &active_wake_locks[type], link)
-                       len += print_lock_stat(page + len, count - len, lock);
+                       ret = print_lock_stat(m, lock);
        }
        spin_unlock_irqrestore(&list_lock, irqflags);
-
-       if (len == count)
-               memcpy(page + len - strlen(TOO_MAY_LOCKS_WARNING),
-                      TOO_MAY_LOCKS_WARNING,
-                      strlen(TOO_MAY_LOCKS_WARNING));
-
-       *eof = 1;
-
-       return len;
+       return 0;
 }
 
 static void wake_unlock_stat_locked(struct wake_lock *lock, int expired)
@@ -535,6 +518,19 @@ int wake_lock_active(struct wake_lock *lock)
 }
 EXPORT_SYMBOL(wake_lock_active);
 
+static int wakelock_stats_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, wakelock_stats_show, NULL);
+}
+
+static const struct file_operations wakelock_stats_fops = {
+       .owner = THIS_MODULE,
+       .open = wakelock_stats_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release,
+};
+
 static int __init wakelocks_init(void)
 {
        int ret;
@@ -569,8 +565,7 @@ static int __init wakelocks_init(void)
        }
 
 #ifdef CONFIG_WAKELOCK_STAT
-       create_proc_read_entry("wakelocks", S_IRUGO, NULL,
-                               wakelocks_read_proc, NULL);
+       proc_create("wakelocks", S_IRUGO, NULL, &wakelock_stats_fops);
 #endif
 
        return 0;