sched: switch sched_features to seqfile

Impact: cleanup

So handling of sched_features read is simplified.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 7dd6c860773b858d7b95821d7e216880c1f1d3be..5419df9cc5c472c6bcce82a138223d26d761f177 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -703,45 +703,18 @@ static __read_mostly char *sched_feat_names[] = {
 
 #undef SCHED_FEAT
 
-static int sched_feat_open(struct inode *inode, struct file *filp)
+static int sched_feat_show(struct seq_file *m, void *v)
 {
-       filp->private_data = inode->i_private;
-       return 0;
-}
-
-static ssize_t
-sched_feat_read(struct file *filp, char __user *ubuf,
-               size_t cnt, loff_t *ppos)
-{
-       char *buf;
-       int r = 0;
-       int len = 0;
        int i;
 
        for (i = 0; sched_feat_names[i]; i++) {
-               len += strlen(sched_feat_names[i]);
-               len += 4;
+               if (!(sysctl_sched_features & (1UL << i)))
+                       seq_puts(m, "NO_");
+               seq_printf(m, "%s ", sched_feat_names[i]);
        }
+       seq_puts(m, "\n");
 
-       buf = kmalloc(len + 2, GFP_KERNEL);
-       if (!buf)
-               return -ENOMEM;
-
-       for (i = 0; sched_feat_names[i]; i++) {
-               if (sysctl_sched_features & (1UL << i))
-                       r += sprintf(buf + r, "%s ", sched_feat_names[i]);
-               else
-                       r += sprintf(buf + r, "NO_%s ", sched_feat_names[i]);
-       }
-
-       r += sprintf(buf + r, "\n");
-       WARN_ON(r >= len + 2);
-
-       r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
-
-       kfree(buf);
-
-       return r;
+       return 0;
 }
 
 static ssize_t
@@ -786,10 +759,17 @@ sched_feat_write(struct file *filp, const char __user *ubuf,
        return cnt;
 }
 
+static int sched_feat_open(struct inode *inode, struct file *filp)
+{
+       return single_open(filp, sched_feat_show, NULL);
+}
+
 static struct file_operations sched_feat_fops = {
-       .open   = sched_feat_open,
-       .read   = sched_feat_read,
-       .write  = sched_feat_write,
+       .open           = sched_feat_open,
+       .write          = sched_feat_write,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = single_release,
 };
 
 static __init int sched_init_debug(void)