proc: convert /proc/$PID/wchan to seq_file interface

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/base.c

@@ -234,7 +234,8 @@ static int proc_pid_auxv(struct seq_file *m, struct pid_namespace *ns,
  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
  * Returns the resolved symbol.  If that fails, simply return the address.
  */
-static int proc_pid_wchan(struct task_struct *task, char *buffer)
+static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
+			  struct pid *pid, struct task_struct *task)
 {
 	unsigned long wchan;
 	char symname[KSYM_NAME_LEN];
@@ -245,9 +246,9 @@ static int proc_pid_wchan(struct task_struct *task, char *buffer)
 		if (!ptrace_may_access(task, PTRACE_MODE_READ))
 			return 0;
 		else
-			return sprintf(buffer, "%lu", wchan);
+			return seq_printf(m, "%lu", wchan);
 	else
-		return sprintf(buffer, "%s", symname);
+		return seq_printf(m, "%s", symname);
 }
 #endif /* CONFIG_KALLSYMS */
 
@@ -2597,7 +2598,7 @@ static const struct pid_entry tgid_base_stuff[] = {
 	DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
 #endif
 #ifdef CONFIG_KALLSYMS
-	INF("wchan",      S_IRUGO, proc_pid_wchan),
+	ONE("wchan",      S_IRUGO, proc_pid_wchan),
 #endif
 #ifdef CONFIG_STACKTRACE
 	ONE("stack",      S_IRUSR, proc_pid_stack),
@@ -2935,7 +2936,7 @@ static const struct pid_entry tid_base_stuff[] = {
 	DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
 #endif
 #ifdef CONFIG_KALLSYMS
-	INF("wchan",     S_IRUGO, proc_pid_wchan),
+	ONE("wchan",     S_IRUGO, proc_pid_wchan),
 #endif
 #ifdef CONFIG_STACKTRACE
 	ONE("stack",      S_IRUSR, proc_pid_stack),