misc_request_fn panic!

[dinghuaming]

hi, when I add some code in misc_request_fn, the system is panic. why?
my os kernel is 3.10.0-1160.71.1.el7.x86_64.

void misc_request_fn(struct request_queue *q, struct bio *bio) {
bio_get(bio);
printk ("we are passing bios.\n");
// here is where we trace requests...
original_request_fn (q, bio);

bio_put(bio);
return;

}

[asimkadav]

what is your code doing? you cannot sleep or add interruptible code here?

[dinghuaming]

i have found the problem.
in function register_block_device(), i use make_request_fn instead of request_fn. then everything is ok.
thank you!

original_request_fn = blkdev_queue->make_request_fn;
blkdev_queue->make_request_fn = misc_request_fn;

// original_request_fn = blkdev_queue->request_fn;
// blkdev_queue->request_fn = misc_request_fn;