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Unknown symbol问题！！急！ [复制链接]

lianxi1999

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发表于 2008-12-05 10:41 |只看该作者 |倒序浏览

我在修改iscsi—target代码的时候遇到了这个问题，自己定义的函数可以编译通过，但是当加载模块的时候就提示我定义的函数和全局变量是Unknown symbol！！
我没有添加代码的时候结果是正确的～～iscsi.h是整个工程的头文件，其他的.c文件的函数都是在这里面定义的。
请高手一定帮忙阿！！我搞了好久了～～
通过dmesg查看结果：
iSCSI Enterprise Target Software - version 0.4.15
iotype_init(92) register fileio
iotype_init(92) register blockio
iotype_init(92) register nullio
iscsi_trgt: Unknown symbol get_ppos
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol init_ppos_table
iscsi_trgt: Unknown symbol set_ppos
iscsi_trgt: Unknown symbol get_ppos
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol set_ppos
iscsi_trgt: Unknown symbol get_ppos
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol set_ppos
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol ppos_table
iscsi_trgt: Unknown symbol ppos_table
iscsi_trgt: Unknown symbol ppos_table
我认为有关的源代码如下：
iscsi.h是原有的代码，table.c注释下的代码是我添加的。

/*
* Copyright (C) 2002-2003 Ardis Technolgies <[email]roman@ardistech.com[/email]>
*
* Released under the terms of the GNU GPL v2.0.
*/
#ifndef __ISCSI_H__
#define __ISCSI_H__
#include <linux/pagemap.h>
#include <linux/seq_file.h>
#include <linux/mm.h>
#include <linux/crypto.h>
#include <net/sock.h>
#include <asm/scatterlist.h>
#include "iscsi_hdr.h"
#include "iet_u.h"
struct iscsi_sess_param {
int initial_r2t;
int immediate_data;
int max_connections;
int max_recv_data_length;
int max_xmit_data_length;
int max_burst_length;
int first_burst_length;
int default_wait_time;
int default_retain_time;
int max_outstanding_r2t;
int data_pdu_inorder;
int data_sequence_inorder;
int error_recovery_level;
int header_digest;
int data_digest;
int ofmarker;
int ifmarker;
int ofmarkint;
int ifmarkint;
};
struct iscsi_trgt_param {
int wthreads;
int target_type;
int queued_cmnds;
};
struct tio {
u32 pg_cnt;
pgoff_t idx;
u32 offset;
u32 size;
struct page **pvec;
atomic_t count;
};
struct network_thread_info {
struct task_struct *task;
unsigned long flags;
struct list_head active_conns;
spinlock_t nthread_lock;
void (*old_state_change)(struct sock *);
void (*old_data_ready)(struct sock *, int);
};
struct worker_thread_info;
struct worker_thread {
struct task_struct *w_task;
struct list_head w_list;
struct worker_thread_info *w_info;
};
struct worker_thread_info {
spinlock_t wthread_lock;
u32 nr_running_wthreads;
struct list_head wthread_list;
struct list_head work_queue;
wait_queue_head_t wthread_sleep;
};
struct iscsi_cmnd;
struct target_type {
int id;
int (*execute_cmnd) (struct iscsi_cmnd *);
};
enum iscsi_device_state {
IDEV_RUNNING,
IDEV_DEL,
};
struct iscsi_target {
struct list_head t_list;
u32 tid;
char name[ISCSI_NAME_LEN];
struct iscsi_sess_param sess_param;
struct iscsi_trgt_param trgt_param;
atomic_t nr_volumes;
struct list_head volumes;
struct list_head session_list;
struct network_thread_info nthread_info;
struct worker_thread_info wthread_info;
struct semaphore target_sem;
struct list_head initiator_list;
u32 initiator_iid_count;
};
struct iscsi_queue {
spinlock_t queue_lock;
struct iscsi_cmnd *ordered_cmnd;
struct list_head wait_list;
int active_cnt;
};
struct iet_volume {
u32 lun;
enum iscsi_device_state l_state;
atomic_t l_count;
struct iscsi_target *target;
struct list_head list;
struct iscsi_queue queue;
u8 scsi_id[SCSI_ID_LEN];
u8 scsi_sn[SCSI_SN_LEN];
u32 blk_shift;
u64 blk_cnt;
u64 reserve_sid;
spinlock_t reserve_lock;
unsigned long flags;
struct iotype *iotype;
void *private;
};
enum lu_flags {
LU_READONLY,
LU_ASYNC,
};
#define LUReadonly(lu) test_bit(LU_READONLY, &(lu)->flags)
#define SetLUReadonly(lu) set_bit(LU_READONLY, &(lu)->flags)
#define LUAsync(lu) test_bit(LU_ASYNC, &(lu)->flags)
#define SetLUAsync(lu) set_bit(LU_ASYNC, &(lu)->flags)
#define IET_HASH_ORDER 8
#define cmnd_hashfn(itt) hash_long((itt), IET_HASH_ORDER)
struct iscsi_session {
struct list_head list;
struct iscsi_target *target;
char *initiator;
u64 sid;
u32 exp_cmd_sn;
u32 max_cmd_sn;
struct iscsi_sess_param param;
u32 max_queued_cmnds;
struct list_head conn_list;
struct list_head pending_list;
spinlock_t cmnd_hash_lock;
struct list_head cmnd_hash[1 << IET_HASH_ORDER];
u32 next_ttt;
struct iscsi_initiator *rinitiator;
};
enum connection_state_bit {
CONN_ACTIVE,
CONN_CLOSING,
};
#define ISCSI_CONN_IOV_MAX (((256 << 10) >> PAGE_SHIFT) + 1)
struct iscsi_conn {
struct list_head list; /* list entry in session list */
struct iscsi_session *session; /* owning session */
u16 cid;
unsigned long state;
u32 stat_sn;
u32 exp_stat_sn;
int hdigest_type;
int ddigest_type;
struct list_head poll_list;
struct file *file;
struct socket *sock;
spinlock_t list_lock;
atomic_t nr_cmnds;
atomic_t nr_busy_cmnds;
struct list_head pdu_list; /* in/outcoming pdus */
struct list_head write_list; /* list of data pdus to be sent */
struct iscsi_cmnd *read_cmnd;
struct msghdr read_msg;
struct iovec read_iov[ISCSI_CONN_IOV_MAX];
u32 read_size;
u32 read_overflow;
int read_state;
struct iscsi_cmnd *write_cmnd;
struct iovec write_iov[ISCSI_CONN_IOV_MAX];
struct iovec *write_iop;
struct tio *write_tcmnd;
u32 write_size;
u32 write_offset;
int write_state;
struct hash_desc rx_hash;
struct hash_desc tx_hash;
struct scatterlist hash_sg[ISCSI_CONN_IOV_MAX];
};
struct iscsi_pdu {
struct iscsi_hdr bhs;
void *ahs;
unsigned int ahssize;
unsigned int datasize;
};
typedef void (iet_show_info_t)(struct seq_file *seq, struct iscsi_target *target);
struct iscsi_cmnd {
struct list_head list;
struct list_head conn_list;
unsigned long flags;
struct iscsi_conn *conn;
struct iet_volume *lun;
struct iscsi_pdu pdu;
struct list_head pdu_list;
struct list_head hash_list;
struct tio *tio;
u32 r2t_sn;
u32 r2t_length;
u32 is_unsolicited_data;
u32 target_task_tag;
u32 outstanding_r2t;
u32 hdigest;
u32 ddigest;
struct iscsi_cmnd *req;
};
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//映射表数据结构
struct ppos_list_node
{
loff_t ppos;
u32 offset;
struct ppos_list_node *next;
};
struct ppos
{
struct ppos_list_node *newppos;
int node_num;
};
struct ppos_table
{
struct ppos ppos_item[1024];
loff_t ppos_now;
};
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#define ISCSI_OP_SCSI_REJECT ISCSI_OP_VENDOR1_CMD
#define ISCSI_OP_PDU_REJECT ISCSI_OP_VENDOR2_CMD
#define ISCSI_OP_DATA_REJECT ISCSI_OP_VENDOR3_CMD
#define ISCSI_OP_SCSI_ABORT ISCSI_OP_VENDOR4_CMD
/* iscsi.c */
extern struct iscsi_cmnd *cmnd_alloc(struct iscsi_conn *, int);
extern void cmnd_rx_start(struct iscsi_cmnd *);
extern void cmnd_rx_end(struct iscsi_cmnd *);
extern void cmnd_tx_start(struct iscsi_cmnd *);
extern void cmnd_tx_end(struct iscsi_cmnd *);
extern void cmnd_release(struct iscsi_cmnd *, int);
extern void send_data_rsp(struct iscsi_cmnd *, int (*)(struct iscsi_cmnd *));
extern void send_scsi_rsp(struct iscsi_cmnd *, int (*)(struct iscsi_cmnd *));
/* tio.c */
extern int tio_init(void);
extern void tio_exit(void);
extern struct tio *tio_alloc(int);
extern void tio_get(struct tio *);
extern void tio_put(struct tio *);
extern void tio_set(struct tio *, u32, loff_t);
extern int tio_read(struct iet_volume *, struct tio *);
extern int tio_write(struct iet_volume *, struct tio *);
extern int tio_sync(struct iet_volume *, struct tio *);
/* iotype.c */
extern struct iotype *get_iotype(const char *name);
extern void put_iotype(struct iotype *iot);
/* params.c */
extern int iscsi_param_set(struct iscsi_target *, struct iscsi_param_info *, int);
/* target_disk.c */
extern struct target_type disk_ops;
/* event.c */
extern int event_send(u32, u64, u32, u32, int);
extern int event_init(void);
extern void event_exit(void);
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/*table.c*/
extern int table_init(void);
extern void table_exit(void);
extern void insert_list(struct ppos_list_node *, struct ppos_list_node *);
extern int init_ppos_table(struct ppos_table *);
extern loff_t set_ppos(loff_t, struct ppos_table *);
extern loff_t get_ppos(loff_t, struct ppos_table *);
extern struct ppos_table *ppos_table;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#define get_pgcnt(size, offset) ((((size) + ((offset) & ~PAGE_CACHE_MASK)) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT)
static inline void iscsi_cmnd_get_length(struct iscsi_pdu *pdu)
{
#if defined(__BIG_ENDIAN)
pdu->ahssize = pdu->bhs.length.ahslength * 4;
pdu->datasize = pdu->bhs.length.datalength;
#elif defined(__LITTLE_ENDIAN)
pdu->ahssize = (pdu->bhs.length & 0xff) * 4;
pdu->datasize = be32_to_cpu(pdu->bhs.length & ~0xff);
#else
#error
#endif
}
static inline void iscsi_cmnd_set_length(struct iscsi_pdu *pdu)
{
#if defined(__BIG_ENDIAN)
pdu->bhs.length.ahslength = pdu->ahssize / 4;
pdu->bhs.length.datalength = pdu->datasize;
#elif defined(__LITTLE_ENDIAN)
pdu->bhs.length = cpu_to_be32(pdu->datasize) | (pdu->ahssize / 4);
#else
#error
#endif
}
#define cmnd_hdr(cmnd) ((struct iscsi_scsi_cmd_hdr *) (&((cmnd)->pdu.bhs)))
#define cmnd_ttt(cmnd) cpu_to_be32((cmnd)->pdu.bhs.ttt)
#define cmnd_itt(cmnd) cpu_to_be32((cmnd)->pdu.bhs.itt)
#define cmnd_opcode(cmnd) ((cmnd)->pdu.bhs.opcode & ISCSI_OPCODE_MASK)
#define cmnd_scsicode(cmnd) cmnd_hdr(cmnd)->scb[0]
#define SECTOR_SIZE_BITS 9
enum cmnd_flags {
CMND_hashed,
CMND_queued,
CMND_final,
CMND_waitio,
CMND_close,
CMND_lunit,
CMND_pending,
CMND_tmfabort,
CMND_rxstart,
};
#define set_cmnd_hashed(cmnd) set_bit(CMND_hashed, &(cmnd)->flags)
#define cmnd_hashed(cmnd) test_bit(CMND_hashed, &(cmnd)->flags)
#define set_cmnd_queued(cmnd) set_bit(CMND_queued, &(cmnd)->flags)
#define cmnd_queued(cmnd) test_bit(CMND_queued, &(cmnd)->flags)
#define set_cmnd_final(cmnd) set_bit(CMND_final, &(cmnd)->flags)
#define cmnd_final(cmnd) test_bit(CMND_final, &(cmnd)->flags)
#define set_cmnd_waitio(cmnd) set_bit(CMND_waitio, &(cmnd)->flags)
#define cmnd_waitio(cmnd) test_bit(CMND_waitio, &(cmnd)->flags)
#define set_cmnd_close(cmnd) set_bit(CMND_close, &(cmnd)->flags)
#define cmnd_close(cmnd) test_bit(CMND_close, &(cmnd)->flags)
#define set_cmnd_lunit(cmnd) set_bit(CMND_lunit, &(cmnd)->flags)
#define cmnd_lunit(cmnd) test_bit(CMND_lunit, &(cmnd)->flags)
#define set_cmnd_pending(cmnd) set_bit(CMND_pending, &(cmnd)->flags)
#define clear_cmnd_pending(cmnd) clear_bit(CMND_pending, &(cmnd)->flags)
#define cmnd_pending(cmnd) test_bit(CMND_pending, &(cmnd)->flags)
#define set_cmnd_tmfabort(cmnd) set_bit(CMND_tmfabort, &(cmnd)->flags)
#define cmnd_tmfabort(cmnd) test_bit(CMND_tmfabort, &(cmnd)->flags)
#define set_cmnd_rxstart(cmnd) set_bit(CMND_rxstart, &(cmnd)->flags)
#define cmnd_rxstart(cmnd) test_bit(CMND_rxstart, &(cmnd)->flags)
#define VENDOR_ID "IET"
#define PRODUCT_ID "VIRTUAL-DISK"
#define PRODUCT_REV "0"
#endif /* __ISCSI_H__ */

复制代码

table.c是我自己实现的文件

#include "iscsi.h"
#include "iscsi_dbg.h"
#include "iotype.h"
void insert_list(struct ppos_list_node *ppos_list, struct ppos_list_node *list_node)
{
list_node->next = ppos_list;
ppos_list = list_node;
}
int init_ppos_table(struct ppos_table *mytable)
{
int i;
mytable = (struct ppos_table *)kzalloc(sizeof(*mytable), GFP_KERNEL);
if(!mytable)
return -ENOMEM;
for(i = 0; i < 1024; i++)
{
mytable->ppos_item[i].newppos = NULL;
mytable->ppos_item[i].node_num = 0;
}
mytable->ppos_now = -1;
return 0;
}
loff_t get_ppos(loff_t ppos, struct ppos_table *mytable)//参数是页面偏移加页内偏移量
{
u32 myoffset;
loff_t myppos;
int i;
i = (int) ppos >> PAGE_CACHE_SHIFT;
myoffset = ppos & ~PAGE_CACHE_MASK;
myppos = mytable->ppos_item[i].newppos->ppos << PAGE_CACHE_SHIFT;
myppos += myoffset;
return myppos;
}
loff_t set_ppos(loff_t ppos, struct ppos_table *mytable) //参数是页面偏移加页内偏移量
{
u32 myoffset;
loff_t myppos;
struct ppos_list_node *newnode;
newnode = kzalloc(sizeof(*newnode), GFP_KERNEL);
newnode->next = NULL;
myoffset = ppos & ~PAGE_CACHE_MASK;
myppos = (int) ppos >> PAGE_CACHE_SHIFT;
newnode->ppos = ++(mytable->ppos_now);
newnode->offset = myoffset;
insert_list(mytable->ppos_item[myppos].newppos, newnode);
return ((mytable->ppos_now << PAGE_CACHE_SHIFT) + myoffset);
}
int table_init(void)
{
int i = init_ppos_table(ppos_table);
return i;
}
void table_exit(void)
{
}

复制代码

file-io.c是调用这些函数的文件,调用代码都在fileio_make_request函数中～～

/*
* Target device file I/O.
* (C) 2004 - 2005 FUJITA Tomonori <[email]tomof@acm.org[/email]>
* This code is licenced under the GPL.
*/
#include <linux/blkdev.h>
#include <linux/writeback.h>
#include <linux/parser.h>
#include "iscsi.h"
#include "iscsi_dbg.h"
#include "iotype.h"
struct fileio_data {
char *path;
struct file *filp;
};
static int fileio_make_request(struct iet_volume *lu, struct tio *tio, int rw)
{
struct fileio_data *p = lu->private;
struct file *filp;
mm_segment_t oldfs;
struct page *page;
u32 offset, size;
loff_t ppos, count,newppos;
char *buf;
int i, err = 0;
ssize_t ret;
assert(p);
filp = p->filp;
size = tio->size;
offset= tio->offset;
ppos = (loff_t) tio->idx << (PAGE_CACHE_SHIFT + 2);
ppos += offset;
for (i = 0; i < tio->pg_cnt; i++) {
page = tio->pvec[i];
assert(page);
buf = page_address(page);
buf += offset;
if (offset + size > PAGE_CACHE_SIZE)
count = PAGE_CACHE_SIZE - offset;
else
count = size;
oldfs = get_fs();
set_fs(get_ds());
[color=Red] if (rw == READ)
{
newppos = get_ppos(ppos, ppos_table);
ret = do_sync_read(filp, buf, count, &newppos);
}
else
{
newppos = set_ppos(ppos, ppos_table);
ret = do_sync_write(filp, buf, count, &newppos);
}[/color]
set_fs(oldfs);
if (ret != count) {
eprintk("I/O error %lld, %ld\n", count, (long) ret);
err = -EIO;
}
size -= count;
offset = 0;
}
assert(!size);
return err;
}
static int fileio_sync(struct iet_volume *lu, struct tio *tio)
{
struct fileio_data *p = lu->private;
struct inode *inode = p->filp->f_dentry->d_inode;
struct address_space *mapping = inode->i_mapping;
loff_t ppos, count;
int res;
if (tio) {
ppos = (loff_t) tio->idx << PAGE_CACHE_SHIFT;
count = tio->size;
} else {
ppos = 0;
count = lu->blk_cnt << lu->blk_shift;
}
res = sync_page_range(inode, mapping, ppos, count);
if (res) {
eprintk("I/O error: syncing pages failed: %d\n", res);
return -EIO;
} else
return 0;
}
static int open_path(struct iet_volume *volume, const char *path)
{
int err = 0;
struct fileio_data *info = volume->private;
struct file *filp;
mm_segment_t oldfs;
int flags;
info->path = kstrdup(path, GFP_KERNEL);
if (!info->path)
return -ENOMEM;
oldfs = get_fs();
set_fs(get_ds());
flags = (LUReadonly(volume) ? O_RDONLY : O_RDWR) | O_LARGEFILE;
filp = filp_open(path, flags, 0);
set_fs(oldfs);
if (IS_ERR(filp)) {
err = PTR_ERR(filp);
eprintk("Can't open %s %d\n", path, err);
info->filp = NULL;
} else
info->filp = filp;
return err;
}
static int set_scsiid(struct iet_volume *volume, const char *id)
{
size_t len;
if ((len = strlen(id)) > SCSI_ID_LEN - VENDOR_ID_LEN) {
eprintk("SCSI ID too long, %zd provided, %u max\n", len,
SCSI_ID_LEN - VENDOR_ID_LEN);
return -EINVAL;
}
memcpy(volume->scsi_id + VENDOR_ID_LEN, id, len);
return 0;
}
static void gen_scsiid(struct iet_volume *volume, struct inode *inode)
{
int i;
u32 *p;
strlcpy(volume->scsi_id, VENDOR_ID, VENDOR_ID_LEN);
for (i = VENDOR_ID_LEN; i < SCSI_ID_LEN; i++)
if (volume->scsi_id[i])
return;
p = (u32 *) (volume->scsi_id + VENDOR_ID_LEN);
*(p + 0) = volume->target->trgt_param.target_type;
*(p + 1) = volume->target->tid;
*(p + 2) = (unsigned int) inode->i_ino;
*(p + 3) = (unsigned int) inode->i_sb->s_dev;
}
static int set_scsisn(struct iet_volume *volume, const char *sn)
{
size_t len;
if ((len = strlen(sn)) > SCSI_SN_LEN) {
eprintk("SCSI SN too long, %zd provided, %u max\n", len,
SCSI_SN_LEN);
return -EINVAL;
}
memcpy(volume->scsi_sn, sn, len);
return 0;
}
enum {
Opt_scsiid, Opt_scsisn, Opt_path, Opt_ignore, Opt_err,
};
static match_table_t tokens = {
{Opt_scsiid, "ScsiId=%s"},
{Opt_scsisn, "ScsiSN=%s"},
{Opt_path, "Path=%s"},
{Opt_ignore, "Type=%s"},
{Opt_ignore, "IOMode=%s"},
{Opt_err, NULL},
};
static int parse_fileio_params(struct iet_volume *volume, char *params)
{
int err = 0;
char *p, *q;
while ((p = strsep(&params, ",")) != NULL) {
substring_t args[MAX_OPT_ARGS];
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_scsiid:
if (!(q = match_strdup(&args[0]))) {
err = -ENOMEM;
goto out;
}
err = set_scsiid(volume, q);
kfree(q);
if (err < 0)
goto out;
break;
case Opt_scsisn:
if (!(q = match_strdup(&args[0]))) {
err = -ENOMEM;
goto out;
}
err = set_scsisn(volume, q);
kfree(q);
if (err < 0)
goto out;
break;
case Opt_path:
if (!(q = match_strdup(&args[0]))) {
err = -ENOMEM;
goto out;
}
err = open_path(volume, q);
kfree(q);
if (err < 0)
goto out;
break;
case Opt_ignore:
break;
default:
eprintk("Unknown %s\n", p);
return -EINVAL;
}
}
out:
return err;
}
static void fileio_detach(struct iet_volume *lu)
{
struct fileio_data *p = lu->private;
kfree(p->path);
if (p->filp)
filp_close(p->filp, NULL);
kfree(p);
lu->private = NULL;
}
static int fileio_attach(struct iet_volume *lu, char *args)
{
int err = 0;
struct fileio_data *p;
struct inode *inode;
if (lu->private) {
printk("already attached ? %d\n", lu->lun);
return -EBUSY;
}
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;
lu->private = p;
if ((err = parse_fileio_params(lu, args)) < 0) {
eprintk("%d\n", err);
goto out;
}
inode = p->filp->f_dentry->d_inode;
gen_scsiid(lu, inode);
if (S_ISREG(inode->i_mode))
;
else if (S_ISBLK(inode->i_mode))
inode = inode->i_bdev->bd_inode;
else {
err = -EINVAL;
goto out;
}
lu->blk_shift = SECTOR_SIZE_BITS;
lu->blk_cnt = inode->i_size >> (lu->blk_shift + 2);
out:
if (err < 0)
fileio_detach(lu);
return err;
}
void fileio_show(struct iet_volume *lu, struct seq_file *seq)
{
struct fileio_data *p = lu->private;
seq_printf(seq, " path:%s\n", p->path);
}
struct iotype fileio =
{
.name = "fileio",
.attach = fileio_attach,
.make_request = fileio_make_request,
.sync = fileio_sync,
.detach = fileio_detach,
.show = fileio_show,
};

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[ 本帖最后由 lianxi1999 于 2008-12-5 11:29 编辑 ]

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发表于 2008-12-05 11:30 |只看该作者

这一系列的：
iscsi_trgt: Unknown symbol get_ppos
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol init_ppos_table
iscsi_trgt: Unknown symbol set_ppos
iscsi_trgt: Unknown symbol get_ppos
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol set_ppos
iscsi_trgt: Unknown symbol get_ppos
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol set_ppos
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol mytable
iscsi_trgt: Unknown symbol ppos_table
iscsi_trgt: Unknown symbol ppos_table
iscsi_trgt: Unknown symbol ppos_table

有两个可行的解决方案：
1. 你可以把定义这些symbol的源文件包进来，一起编译；
2. 这些symbol，他们的头文件可能你确实包进来了；但是，对于Linux内核模块，如果相应模块并没有调用EXPORT_SYMBOL() or EXPORT_SYMBOL_GPL()——模块导出符号表可供其它模块引用。那么其他模块去引用它，当然就不行了。