Failed to add File In proc system. Depressed. Please advise me

Failed to add File In proc system. Depressed. For more information, see Linux programming and kernel. The main problem is
[Root @ localhost proc_example] # make-C/usr/src/kernels/2.6.21-1.3194.fc7-i686 SUBDIRS = $ PWD modules
Make: Entering directory '/usr/src/kernels/2.6.21-1.3194.fc7-i686'
CC [M]/home/OS/module/proc_example/proc_example.o
/Home/OS/module/proc_example/proc_example.c: 8: 1: Warning: "MODULE_VERSION" redefinition
In a file containing/home/OS/module/proc_example/proc_example.c: 1:
Include/linux/module. h: 155: 1: Warning: This is the previously defined location
/Home/OS/module/proc_example/proc_example.c: In the 'init _ module' function:
/Home/OS/module/proc_example/proc_example.c: 64: Warning: Assignment of incompatible pointer types
/Home/OS/module/proc_example/proc_example.c: 70: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 71: Warning: transfer between incompatible pointer types when passing parameter 3 (belonging to 'create _ proc_read_entry ')
/Home/OS/module/proc_example/proc_example.c: 71: Warning: Assignment of incompatible pointer types
/Home/OS/module/proc_example/proc_example.c: 77: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 80: Warning: conversion between incompatible pointer types when passing parameter 3 ('create _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 80: Warning: Assignment of incompatible pointer types
/Home/OS/module/proc_example/proc_example.c: 81: warning: we recommend that you add parentheses before and after the value assignment statement used as the true value.
/Home/OS/module/proc_example/proc_example.c: 88: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 89: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 90: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 91: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 93: Warning: transfer between incompatible pointer types when passing parameter 3 (which belongs to 'create _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 93: Warning: Assignment of incompatible pointer types
/Home/OS/module/proc_example/proc_example.c: 101: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 102: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 103: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 104: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 107: Warning: Implicit declaration function 'proc _ mkdnod'
/Home/OS/module/proc_example/proc_example.c: 107: Warning: assign an integer to the pointer when assigning a value without type conversion
/Home/OS/module/proc_example/proc_example.c: 112: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 114: Warning: conversion between incompatible pointer types when passing parameter 2 (belonging to 'proc _ symlink ')
/Home/OS/module/proc_example/proc_example.c: 114: Warning: Assignment of incompatible pointer types
/Home/OS/module/proc_example/proc_example.c: 119: Error: Leading pointer to incomplete type
/Home/OS/module/proc_example/proc_example.c: 123: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 126: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 131: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 134: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: In the 'cleanup _ module' function:
/Home/OS/module/proc_example/proc_example.c: 144: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 146: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 149: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 151: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: 153: Warning: conversion between incompatible pointer types when passing parameter 2 (which belongs to 'remove _ proc_entry ')
/Home/OS/module/proc_example/proc_example.c: At the top layer:
/Home/OS/module/proc_example/proc_example.c: 159: Warning: No data type or storage class is defined.
/Home/OS/module/proc_example/proc_example.c: 159: Warning: In the 'export _ NO_SYMBOLS 'Declaration, the default type is 'int'
Make [1]: *** [/home/OS/module/proc_example/proc_example.o] Error 1
Make: *** [_ module _/home/OS/module/proc_example] Error 2
Make: Leaving directory '/usr/src/kernels/2.6.21-1.3194.fc7-i686'
Can the old birds tell us the cause of the error. Thank you.