proc: : uninline name_to_int()

Save ~360 bytes.

	add/remove: 1/0 grow/shrink: 0/4 up/down: 104/-463 (-359)
	function                                     old     new   delta
	name_to_int                                    -     104    +104
	proc_pid_lookup                              217     126     -91
	proc_lookupfd_common                         212     121     -91
	proc_task_lookup                             289     194     -95
	__proc_create                                588     402    -186

Link: http://lkml.kernel.org/r/20170912194850.GA17730@avx2
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>
diff --git a/fs/proc/util.c b/fs/proc/util.c
new file mode 100644
index 0000000..c29aa49
--- /dev/null
+++ b/fs/proc/util.c
@@ -0,0 +1,23 @@
+#include <linux/dcache.h>
+
+unsigned name_to_int(const struct qstr *qstr)
+{
+	const char *name = qstr->name;
+	int len = qstr->len;
+	unsigned n = 0;
+
+	if (len > 1 && *name == '0')
+		goto out;
+	while (len-- > 0) {
+		unsigned c = *name++ - '0';
+		if (c > 9)
+			goto out;
+		if (n >= (~0U-9)/10)
+			goto out;
+		n *= 10;
+		n += c;
+	}
+	return n;
+out:
+	return ~0U;
+}