proc: switch /proc/version to seq_file

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

fs/proc/Makefile

@@ -12,6 +12,7 @@ proc-y       += inode.o root.o base.o generic.o array.o \
 proc-y	+= loadavg.o
 proc-y	+= meminfo.o
 proc-y	+= uptime.o
+proc-y	+= version.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

@@ -115,18 +115,6 @@ static const struct file_operations proc_zoneinfo_file_operations = {
 	.release	= seq_release,
 };
 
-static int version_read_proc(char *page, char **start, off_t off,
-				 int count, int *eof, void *data)
-{
-	int len;
-
-	len = snprintf(page, PAGE_SIZE, linux_proc_banner,
-		utsname()->sysname,
-		utsname()->release,
-		utsname()->version);
-	return proc_calc_metrics(page, start, off, count, eof, len);
-}
-
 extern const struct seq_operations cpuinfo_op;
 static int cpuinfo_open(struct inode *inode, struct file *file)
 {
@@ -680,7 +668,6 @@ void __init proc_misc_init(void)
 		char *name;
 		int (*read_proc)(char*,char**,off_t,int,int*,void*);
 	} *p, simple_ones[] = {
-		{"version",	version_read_proc},
 #ifdef CONFIG_PROC_HARDWARE
 		{"hardware",	hardware_read_proc},
 #endif

fs/proc/version.c

+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/utsname.h>
+
+static int version_proc_show(struct seq_file *m, void *v)
+{
+	seq_printf(m, linux_proc_banner,
+		utsname()->sysname,
+		utsname()->release,
+		utsname()->version);
+	return 0;
+}
+
+static int version_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, version_proc_show, NULL);
+}
+
+static const struct file_operations version_proc_fops = {
+	.open		= version_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init proc_version_init(void)
+{
+	proc_create("version", 0, NULL, &version_proc_fops);
+	return 0;
+}
+module_init(proc_version_init);