Can you past the panic log, please?
On Fri, Apr 3, 2009 at 4:22 PM, nidhi mittal <nidhimittal19@xxxxxxxxx> wrote:
> Hi all
> i have already posted this also .but still not solved ..really need help
>
> MY aim :
> in simple ram based block dev driver
> wherein
> in request function -- dequeue the req from req queue and add it to the
> linked list
> then in the function triggered by timer
> handle each req from the linked list
> then blk_end_requets is called upon completion of request .
>
>
> i have tried all possible code modifications so many of times but each time
> i have to reboot after crash ...and that too doesnt leave any log message
> i am sending important parts of code it will be very kind if someone sees
> thru it some mistake i am making ...
> .
> i am highlighting error prone areas what i am guessing ..some prob in handle
> timer is there
>
> Important point pl consider
> the request processing code used in handle_timer has been successfully
> running
> when i dont use that in timer and just process request segment by segment in
> normal request function only .
> i guess some problem is with using __bio_kmap_atomic in timer function i
> guess is it ?
>
>
> Important Data Structures are :
>
> struct filtered_request_queue {
> spinlock_t lock;
> struct list_head link;
> };/*this queue is in kernel space only */
>
> struct filtered_request {
> struct request* req;
> struct list_head link; /* linked list of requests
> */
> };
>
> struct filtered_request_queue *frqp=NULL;
> *************************************************************************************************************************
> /*This function is called from init_module function */
>
> static void init_filtered_linked_list(void)
> {
> /*
> just initializes frqp --- nothing more than that can be ignored
> */
> frqp=(struct filtered_request_queue*)kzalloc(sizeof(struct
> filtered_request_queue),GFP_KERNEL);
> INIT_LIST_HEAD(&(frqp->link));
> spin_lock_init(&(frqp->lock));
> }
>
>
>
> static void blkdev_req_fn(struct request_queue *q)
> {
> struct request *req;
> struct filtered_request * my_req=NULL;
> unsigned long flags=0;
> while((req = elv_next_request(q)) != NULL){
> if(!blk_fs_request(req)){
> end_request(req, 0);
> continue;
> }
> blkdev_dequeue_request(req);
> my_req = (struct filtered_request*)kzalloc(sizeof(struct
> filtered_request),GFP_ATOMIC);
> my_req->req=req;
> spin_lock_irqsave(&(frqp->lock),flags);
> list_add_tail(&(my_req->link),&(frqp->link));
> spin_unlock_irqrestore(&(frqp->lock),flags);
> printk(KERN_ALERT"i m going out of req function ");
>
> }//while
> }
>
>
> static void set_timer_req_process(void)
> {
> init_timer(&timer);
> timer.function=handle_timer;
> timer.expires=jiffies+(5*HZ);
> add_timer(&timer);
> }
>
>
> static void handle_timer(unsigned long data)
> {
> struct filtered_request *pos;
> struct request *my_req;
>
> struct bio_vec *bvec;
> struct req_iterator iter;
> struct bio *curr_bio;
> int i;
>
> sector_t sector ;
> int nsect = 0;
> unsigned long nr_bytes;
>
> unsigned long flags;
> struct blkdev_device *dev;
> char *buffer;
> dev = dev_struct;
>
> spin_lock_irqsave(&(frqp->lock),flags);
> if(!list_empty(&(frqp->link)))
> {
> list_for_each_entry(pos,&(frqp->link),link)
> {
> my_req = pos->req;
> sector=my_req->sector;
> rq_for_each_segment(bvec, my_req, iter)
> {
> curr_bio = iter.bio;
> i=iter.i;
> buffer = __bio_kmap_atomic(curr_bio,i,KM_USER0);
>
> data_transfer(dev,sector,bio_cur_sectors(curr_bio),buffer,
> bio_data_dir(curr_bio) == WRITE);
> sector += bio_cur_sectors(curr_bio);
> nsect += bio_cur_sectors(curr_bio);
> __bio_kunmap_atomic(curr_bio, KM_USER0);
> }
> nr_bytes=nsect*512;
> blk_end_request(my_req,0,nr_bytes)
> pos->req=NULL;
> }//list_for_each_entry
> }//!list_empty
> if(!list_empty(&(frqp->link)))
> {
> list_for_each_entry(pos,&(frqp->link),link)
> {
> list_del(&(pos->link));
> kfree(pos);
> }
> }
> spin_unlock_irqrestore(&(frqp->lock),flags);
> set_timer_req_process();
> }//function
>
>
> pl help i m stuck here totallygetting no clue at all ....same code works
> when used in normal request function ...but same code when processes request
> segment by segment in timer function ...crashes kernel ..pl pl help ...
>
> **if someone needs i can send full code too ...
>
>
>
> --
> Thanks & Regards
> Nidhi
>
--
Pradeep
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