lkml.org 
[lkml]   [2006]   [Apr]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectIssues with removable media
Dear Linux Kernel Govers,

I have read through the LDD3 & LWN and got a fair understanding about
implementing Linux removable block driver. I made an attempt to
simulate the Removable media in a Simple block driver module.

I am doing the following when trying to simulate the Removable media:

/******* Simple block Driver request ********/

static void sbd_request(request_queue_t *q)
{
struct request *req;
int status;

while ((req = elv_next_request(q)) != NULL) {
if (! blk_fs_request(req)) {
printk (KERN_NOTICE "Skip non-CMD request\n");
end_request(req, 0);
continue;
}

/* Simple memcpy based on the request ; Returns success or
failure which is passed to end_that_request_first() */
status = sbd_transfer(&Device, req->sector, req->current_nr_sectors,
req->buffer, rq_data_dir(req));

if(!end_that_request_first(req, status, req->current_nr_sectors)) {
blkdev_dequeue_request(req);
end_that_request_last(req);
}
}

Then, I prepared an IOCTL to simulate the removable media to the kernel.

When the applications issues IOCTL, it performs the following to
notify the kernel of removed disk.

/* Simulate the Removal Media Disk */
Case REMOVE_MOUNTED_DISK:

if(Device.bdev)
invalidate_bdev(Device.bdev,1);
del_gendisk(Device.gd);
put_disk(Device.gd);
blk_cleanup_queue(Queue);
vfree(Device.data);
return 0;

when I issue #ls /mnt (mount point) ( i.e. after the application
issues the IOCTL)
the Kernel crashes,
OR
it crashes when tried to unload the module.

I have been trying hard to understand the real problem with this
module a long time from now.

What wrong am I doing in this module?
I will provide you with source code if you need it any time.
Please let me know what additional things should I handle when writing
code for removable media?

Regards,
Mukund Jampala
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-04-25 16:50    [W:0.030 / U:0.672 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site