proc: switch /proc/uptime to seq_file

and move it to fs/proc/uptime.c while I'm at it.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

fs/proc/Makefile

@@ -10,6 +10,7 @@ proc-$(CONFIG_MMU)	:= mmu.o task_mmu.o
 proc-y       += inode.o root.o base.o generic.o array.o \
 		proc_tty.o proc_misc.o
 proc-y	+= loadavg.o
+proc-y	+= uptime.o
 proc-$(CONFIG_PROC_SYSCTL)	+= proc_sysctl.o
 proc-$(CONFIG_NET)		+= proc_net.o
 proc-$(CONFIG_PROC_KCORE)	+= kcore.o

fs/proc/proc_misc.c

@@ -78,26 +78,6 @@ static int proc_calc_metrics(char *page, char **start, off_t off,
 	return len;
 }
 
-static int uptime_read_proc(char *page, char **start, off_t off,
-				 int count, int *eof, void *data)
-{
-	struct timespec uptime;
-	struct timespec idle;
-	int len;
-	cputime_t idletime = cputime_add(init_task.utime, init_task.stime);
-
-	do_posix_clock_monotonic_gettime(&uptime);
-	monotonic_to_bootbased(&uptime);
-	cputime_to_timespec(idletime, &idle);
-	len = sprintf(page,"%lu.%02lu %lu.%02lu\n",
-			(unsigned long) uptime.tv_sec,
-			(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
-			(unsigned long) idle.tv_sec,
-			(idle.tv_nsec / (NSEC_PER_SEC / 100)));
-
-	return proc_calc_metrics(page, start, off, count, eof, len);
-}
-
 int __attribute__((weak)) arch_report_meminfo(char *page)
 {
 	return 0;
@@ -836,7 +816,6 @@ void __init proc_misc_init(void)
 		char *name;
 		int (*read_proc)(char*,char**,off_t,int,int*,void*);
 	} *p, simple_ones[] = {
-		{"uptime",	uptime_read_proc},
 		{"meminfo",	meminfo_read_proc},
 		{"version",	version_read_proc},
 #ifdef CONFIG_PROC_HARDWARE

fs/proc/uptime.c

+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/time.h>
+#include <asm/cputime.h>
+
+static int uptime_proc_show(struct seq_file *m, void *v)
+{
+	struct timespec uptime;
+	struct timespec idle;
+	cputime_t idletime = cputime_add(init_task.utime, init_task.stime);
+
+	do_posix_clock_monotonic_gettime(&uptime);
+	monotonic_to_bootbased(&uptime);
+	cputime_to_timespec(idletime, &idle);
+	seq_printf(m, "%lu.%02lu %lu.%02lu\n",
+			(unsigned long) uptime.tv_sec,
+			(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
+			(unsigned long) idle.tv_sec,
+			(idle.tv_nsec / (NSEC_PER_SEC / 100)));
+	return 0;
+}
+
+static int uptime_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, uptime_proc_show, NULL);
+}
+
+static const struct file_operations uptime_proc_fops = {
+	.open		= uptime_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init proc_uptime_init(void)
+{
+	proc_create("uptime", 0, NULL, &uptime_proc_fops);
+	return 0;
+}
+module_init(proc_uptime_init);