On Sun, Jun 05, 2011 at 06:09:50PM +0430, Amirali Shambayati wrote:

Hello all,
I wanted to use list data structure implemented inside kernel. It seems that
it is too different with usual concept from a list data structure. I studied
about it, and I thought that I got familiar enough to use it. I have
implemented a two-dimensioned list, using what I understood about kernel
list.  But as I debugged my code, it seems that my concept is wrong. Would
anyone guide me how to implement a two-dimensioned list, or introduce me a
manual to learn about it more?

http://lwn.net/Articles/262464/ (What is RCU, Fundamentally?) includes
a bit of description of the linked lists used in the kernel, maybe this
helps a bit.

A good example of a structure with two list_heads is struct task_struct
(include/linux/sched.h, line 1311):
	...
	/*
	 * children/sibling forms the list of my natural children
	 */
	struct list_head children;	/* list of my children */
	struct list_head sibling;       /* linkage in my parent's children list */
	...

I have two data structures called "noop_data" and "bundle". I have a list of
bundles, which each one has a list of requests.
I implemented it, this way:
"noop_data" has a reference to start point of bundles list, called
"writeQueue"
"bundle" has a reference to start point of requests list, called
"reqsQueue".
"bundle" knows its related list using "bundlesQueue".
"request" knows its related list using "queuelist". (request struct is
already implemented in kernel)

struct bundle {
    int bundleNumber;
    int size;
    struct list_head bundlesQueue;
    struct list_head reqsQueue;
    int filled[8];
};

struct noop_data {
    struct list_head readQueue;
    struct list_head writeQueue;
    struct bundle bun;

Why are you embedding a struct bundle here?

    unsigned int starved;
};

I can't see anything fundamentally wrong with this. Maybe your list-
walking code is wrong, somewhere.

HTH,
	Jonathan Neusch?fer