2.6.36中struct file_operations 的变化

最近在做Linux驱动方面的东西。发现涉及到.ioctl部分存在着问题。我的电脑是2.6.32.127的内核，这个用起来没有问题。而我把它放到2.6.36的内核中就有了问题，报错为.ioctl不存在。我特意查了源码中的相关定义，发现2.6.36中少了

int (*ioctl) (struct inode *, struct file *, unsigned int,unsigned long);

这一行，而仅剩下

 long (*unlocked_ioctl) (struct file *,unsigned int, unsigned long);
 long (*compat_ioctl) (struct file *, unsignedint, unsigned long);

这两行关于ioctl操作的函数

 

在这种情况下，我们只能用long (*unlocked_ioctl) (struct file *, unsigned int,unsigned long);来替换掉之前的int (*ioctl) (struct inode *, struct file *,unsigned int, unsigned long);但是还是存在着问题，即他们的返回值是不同的。

unlocked_ioctl: long ioctl(struct file *filp, unsigned int cmd,unsigned long args);

old ioctl: int ioctl(struct inode *inode, struct file *filp,unsigned int cmd, unsigned long args);

同时unlocked_ioctl去除了"inode" 函数指针(which can be obtained anywaysthrough the filp),

另外The 'inode' value that was passed to 'ioctl' function isavailable for use with the'unlocked_ioctl' function by way offilp->d_entry->d_inode:
    long(*unlocked_ioctl) (struct file *filp, unsigned intcmd, unsigned long arg);
    ...
    struct inode*inode = filp->d_entry->d_inode;

There is a nice explanation of this at http://lwn.net/Articles/119652/

 

其在几个版本中的具体定义如下：

 

2.6.36的fs.h中file_operations 定义

#define HAVE_COMPAT_IOCTL 1
#define HAVE_UNLOCKED_IOCTL 1

struct file_operations {
 struct module *owner;
 loff_t (*llseek) (struct file *, loff_t,int);
 ssize_t (*read) (struct file *, char __user *,size_t, loff_t *);
 ssize_t (*write) (struct file *, const char__user *, size_t, loff_t *);
 ssize_t (*aio_read) (struct kiocb *, const structiovec *, unsigned long, loff_t);
 ssize_t (*aio_write) (struct kiocb *, conststruct iovec *, unsigned long, loff_t);
 int (*readdir) (struct file *, void *,filldir_t);
 unsigned int (*poll) (struct file *, structpoll_table_struct *);
 long (*unlocked_ioctl) (struct file *, unsignedint, unsigned long);
 long (*compat_ioctl) (struct file *, unsignedint, unsigned long);
 int (*mmap) (struct file *, struct vm_area_struct*);
 int (*open) (struct inode *, struct file*);
 int (*flush) (struct file *, fl_owner_tid);
 int (*release) (struct inode *, struct file*);
 int (*fsync) (struct file *, int datasync);
 int (*aio_fsync) (struct kiocb *, intdatasync);
 int (*fasync) (int, struct file *, int);
 int (*lock) (struct file *, int, struct file_lock*);
 ssize_t (*sendpage) (struct file *, struct page*, int, size_t, loff_t *, int);
 unsigned long (*get_unmapped_area)(struct file *,unsigned long, unsigned long,

unsigned long, unsigned long);
 int (*check_flags)(int);
 int (*flock) (struct file *, int, structfile_lock *);
 ssize_t (*splice_write)(struct pipe_inode_info *,struct file *, loff_t *, size_t,

unsigned int);
 ssize_t (*splice_read)(struct file *, loff_t *,struct pipe_inode_info *, size_t,

unsigned int);
 int (*setlease)(struct file *, long, structfile_lock **);
};

 

2.6.34版本的fs.h这里如下

1480 // 
1481 // NOTE: 
1482 // read, write, poll, fsync, readv, writev,unlocked_ioctl and compat_ioctl 
1483 // can be called without the big kernel lockheld in all filesystems. 
1484 // 
1485 struct file_operations{  
1486        struct module *owner;  
1487        loff_t (*llseek) (struct file *, loff_t,int);  
1488        ssize_t (*read) (struct file *, char __user *, size_t, loff_t*);  
1489        ssize_t (*write) (struct file *, const char __user *, size_t,loff_t *);  
1490        ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsignedlong, loff_t);  
1491        ssize_t (*aio_write) (struct kiocb *, const struct iovec *,unsigned long, loff_t);  
1492        int (*readdir) (struct file *, void *,filldir_t);  
1493        unsigned int (*poll) (struct file *, struct poll_table_struct*);  
1494        int (*ioctl) (struct inode *, struct file *, unsigned int, unsignedlong);  
1495        long (*unlocked_ioctl) (struct file *, unsigned int, unsignedlong);  
1496        long (*compat_ioctl) (struct file *, unsigned int, unsignedlong);  
1497        int (*mmap) (struct file *, struct vm_area_struct*);  
1498        int (*open) (struct inode *, struct file*);  
1499        int (*flush) (struct file *, fl_owner_tid);  
1500        int (*release) (struct inode *, struct file*);  
1501        int (*fsync) (struct file *, struct dentry *, intdatasync);  
1502        int (*aio_fsync) (struct kiocb *, intdatasync);  
1503        int (*fasync) (int, struct file *,int);  
1504        int (*lock) (struct file *, int, struct file_lock*);  
1505        ssize_t (*sendpage) (struct file *, struct page *, int, size_t,loff_t *, int);  
1506        unsigned long (*get_unmapped_area)(struct file *, unsigned long,unsigned long, unsigned long, unsignedlong);  
1507        int (*check_flags)(int);  
1508        int (*flock) (struct file *, int, struct file_lock*);  
1509        ssize_t (*splice_write)(struct pipe_inode_info *, struct file *,loff_t *, size_t, unsignedint);  
1510        ssize_t (*splice_read)(struct file *, loff_t *, structpipe_inode_info *, size_t, unsignedint);  
1511        int (*setlease)(struct file *, long, struct file_lock**);  
1512 }; 

2.6.32.2的fs.h中file_operations 定义

//These macros are for out of kernel modules to test that
// the kernel supports the unlocked_ioctl andcompat_ioctl
// fields in struct file_operations.
#define HAVE_COMPAT_IOCTL 1
#define HAVE_UNLOCKED_IOCTL 1

//
// NOTE:
// read, write, poll, fsync, readv, writev,unlocked_ioctl and compat_ioctl
 // can be called without the big kernel lock heldin all filesystems.
 //
struct file_operations {
 struct module *owner;
 loff_t (*llseek) (struct file *, loff_t,int);
 ssize_t (*read) (struct file *, char __user *,size_t, loff_t *);
 ssize_t (*write) (struct file *, const char__user *, size_t, loff_t *);
 ssize_t (*aio_read) (struct kiocb *, const structiovec *, unsigned long, loff_t);
 ssize_t (*aio_write) (struct kiocb *, conststruct iovec *, unsigned long, loff_t);
 int (*readdir) (struct file *, void *,filldir_t);
 unsigned int (*poll) (struct file *, structpoll_table_struct *);
 int (*ioctl) (struct inode *, struct file *,unsigned int, unsigned long);
 long (*unlocked_ioctl) (struct file *, unsignedint, unsigned long);
 long (*compat_ioctl) (struct file *, unsignedint, unsigned long);
 int (*mmap) (struct file *, struct vm_area_struct*);
 int (*open) (struct inode *, struct file*);
 int (*flush) (struct file *, fl_owner_tid);
 int (*release) (struct inode *, struct file*);
 int (*fsync) (struct file *, struct dentry *, intdatasync);
 int (*aio_fsync) (struct kiocb *, intdatasync);
 int (*fasync) (int, struct file *, int);
 int (*lock) (struct file *, int, struct file_lock*);
 ssize_t (*sendpage) (struct file *, struct page*, int, size_t, loff_t *, int);
 unsigned long (*get_unmapped_area)(struct file *,unsigned long, unsigned long,

unsigned long, unsigned long);
 int (*check_flags)(int);
 int (*flock) (struct file *, int, structfile_lock *);
 ssize_t (*splice_write)(struct pipe_inode_info *,struct file *, loff_t *, size_t,

unsigned int);
 ssize_t (*splice_read)(struct file *, loff_t *,struct pipe_inode_info *, size_t,

unsigned int);
 int (*setlease)(struct file *, long, structfile_lock **);
};