I am again repeating the steps, i found something interested, when I am doing make after making EXPORT_SYMBOL entries in fs/drop_caches.c ( during kernel compilation); I am getting following warning messages for each of the exported function from this file only, the messages are:
data definition has no type or storage class type defaults to 'int' in declaration of 'EXPORT_SYMBOL' parameter names (without types) in function declaration Although these are the warning messages, but why it is coming from fs/drop_caches file only. The function which I have exported from fs/buffer.c and block/genhd.c are easily exported and there is no warning messages against any exported function from other than fs/drop_caches.c On Tue, Jul 21, 2009 at 10:30 AM, Mulyadi Santosa <[email protected] > wrote: > On Mon, Jul 20, 2009 at 9:40 PM, er krishna<[email protected]> wrote: > > 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 > > Upper case T, according to "man nm" means it's a global symbol. In > other word, other function located in separate object file could > reference it. OK, seems you do correctly here in exporting symbol > > > These entries are quite different from the actual exported functions from > > other files, it has only T option. > > What do you mean by the above paragraph? > Mylyadi, Actually when we do compilation, there are warning messages and when i do insmod there is error and in dmesg it shows that the above symbols are not resolved (it means there is a linking error) , I have exported some other function from other file and checked all those entries in /proc/kallsyms and in System.map file. These are different in nature. Thats why I asked ? > Other than that, as Peter has suggested, are you sure you have > declared drop_slab() etc as "extern" function in your module? > As I have declared their definition in linux/mm.h, I dont think that i have to do extern in my module coz i have included linux/mm.h after making proper declaration of these functions. But let me check with extern once more. > > And as far as I can see here, they are warning messages so there's a > chance the final kernel module can be successfully build. What happen > if you do "insmod -f"? Does it work as expected? > I will let you know after repeating the above steps, coz I am once again compiling the kernel. > > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer > blog: the-hydra.blogspot.com >
