sorry...let me debug my statement, one more thing to do: d. and from the function user side (whoever use the function) "extern drop_pagecache()" have to be declared. On Tue, Jul 21, 2009 at 8:03 AM, Peter Teoh<htmldeveloper@xxxxxxxxx> wrote: > since drop_cache is part of kernel, u have to do 3 things: > > a. declare EXPORT_SYMBOL() at the end of the fs/drop_caches.c file. > b. remove the "static" in front of drop_pagecache() declaration. > c. recompile the kernel + modules etc, and reboot into the new kernel. > > On Tue, Jul 21, 2009 at 12:35 AM, er krishna<erkrishna@xxxxxxxxx> wrote: >> >> >> On Mon, Jul 20, 2009 at 9:54 PM, SandeepKsinha <sandeepksinha@xxxxxxxxx> >> wrote: >>> >>> Hi Krishna, >>> >>> >>> >>> On Mon, Jul 20, 2009 at 8:10 PM, er krishna <erkrishna@xxxxxxxxx> wrote: >>>> >>>> >>>> >>>> Dear All, >>>> >>>> >>>> >>>> I have one simple problem in exporting the function. Everything is >>>> fine, but its not working as per the expectation. Actually I have to export >>>> some function from fs/dropcache.c, but it is not working as per the >>>> expectataion, [ I am able to export any function from other files like >>>> fs/buffer.c and block/genhd.c but dropcache.c creates a problem] .I am >>>> attaching the file. Just once check & please tell if something is missing, >>>> what I have done is as follows: >>>> >>>> >>>> >>>> I have exported three functions from fs/dropcaches.c by making their >>>> function declaration in linux/mm.h, compiled the corresponding 2.6.26 >>>> kernel & got their entries in System.map file as follows: >>>> >>>> >>>> c0174d98 T drop_slab >>>> c0174db2 T drop_pagecache >>>> c0174ea7 T drop_caches_sysctl_handler >>>> >>>> These entries are quite different from the actual exported functions from >>>> other files, it has only T option. Can antbody elaborate what is the meaning >>>> of these options like T, t, r , u and so on? >>>> >>>> I have booted with same 2.6.26 kernel. I included linux/mm.h and all >>>> the above three function in my module done make & found following warnings >>>> in compilation & following error message in insmod due to some linking >>>> error: >>>> >>>> >>>> [root@CENTOS2 kernel]# make >>>> make -C /lib/modules/2.6.26/build M=/root/kernel modules >>>> make[1]: Entering directory `/root/Desktop/linux-2.6.26' >>>> Building modules, stage 2. >>>> MODPOST 2 modules >>>> WARNING: "drop_slab" [/root/kernel/dropcache.ko] undefined! >>>> WARNING: "drop_pagecache" [/root/kernel/dropcache.ko] undefined! >>>> WARNING: "drop_caches_sysctl_handler" [/root/kernel/dropcache.ko] >>>> undefined! >>>> make[1]: Leaving directory `/root/Desktop/linux-2.6.26' >>>> [root@CENTOS2 kernel]# >>>> [root@CENTOS2 kernel]# >>>> [root@CENTOS2 kernel]# insmod dropcache.ko >>>> insmod: error inserting 'dropcache.ko': -1 Unknown symbol in module >>> >>> Do a dmesg and provide the results? >>> >>> You will see that which symbol still remains unresolved. May be you need >>> to export some more of them. >> >> dropcache: module license 'unspecified' taints kernel. >> dropcache: Unknown symbol drop_slab >> dropcache: Unknown symbol drop_pagecache >> dropcache: Unknown symbol drop_caches_sysctl_handler >> >> >> Actually what happend I have made some own functiion and put those function >> in different files, all of the function from other files are exported easily >> but the function from this particular file is not exported due to linking >> error. I suspect the entries which it created in System.map file is also not >> good. Anybody knows various options of system.map file the please tell me. I >> am attaching system.map file . >> >> >>> >>> >>>> >>>> [root@CENTOS2 kernel]# >>>> [root@CENTOS2 kernel]# >>>> >>>> >>>> Any idea how to trace it & what is missing, as I got all the exported >>>> entries in System.map file & I have included the function declaration file >>>> linux/mm.h on the same compiled kernel, it should do the things in right >>>> manner. >>>> >>>> Please suggest, If I am missing something or you want any more >>>> information. I am attaching my kernel module and these are some more snippet >>>> : >>>> [root@CENTOS2 kernel]# uname -a >>>> Linux CENTOS2 2.6.26 #1 SMP Sun Jul 19 10:54:05 IST 2009 i686 i686 i386 >>>> GNU/Linux >>>> [root@CENTOS2 kernel]# >>>> [root@CENTOS2 kernel]# tail -1 >>>> /root/Desktop/linux-2.6.26/fs/drop_caches.c >>>> EXPORT_SYMBOL(drop_caches_sysctl_handler); >>>> [root@CENTOS2 kernel]# >>>> [root@CENTOS2 kernel]# >>>> >>>> >>>> >>> >>> Regards, >>> Sandeep. >>> >>> >>> >>> >>> >>> >>> “To learn is to change. Education is a process that changes the learner.” >>> >>> >>> >>> >>> >>>> >>>> >>>> >>>> >>>> >>>> Thanks and Best Regards, >>>> ------------------------ >>>> Krishna Kumar >>>> >>>> >>> >> >> > > > > -- > Regards, > Peter Teoh > -- Regards, Peter Teoh -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
