proc: move fs/proc/inode-alloc.txt comment into a source file

so that people will realize that it exists and can update it as needed.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

fs/proc/generic.c

@@ -307,6 +307,21 @@ static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
 /*
  * Return an inode number between PROC_DYNAMIC_FIRST and
  * 0xffffffff, or zero on failure.
+ *
+ * Current inode allocations in the proc-fs (hex-numbers):
+ *
+ * 00000000		reserved
+ * 00000001-00000fff	static entries	(goners)
+ *      001		root-ino
+ *
+ * 00001000-00001fff	unused
+ * 0001xxxx-7fffxxxx	pid-dir entries for pid 1-7fff
+ * 80000000-efffffff	unused
+ * f0000000-ffffffff	dynamic entries
+ *
+ * Goal:
+ *	Once we split the thing into several virtual filesystems,
+ *	we will get rid of magical ranges (and this comment, BTW).
  */
 static unsigned int get_inode_number(void)
 {