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>

1 files changed, 16 insertions, 36 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 7dd6c860773b..5419df9cc5c4 100644
--- 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)