>>> On 23.02.11 at 11:38, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:
> Any reason why in .32 and newer you still don't use
> __register_chrdev() (and __unregister_chrdev())? And even
> if this still needs to be this way, I note that unregister_chrdev()
> calls __unregister_chrdev_region() before cdev_del(), while
> blktap_ring_exit() does it the other way around?
I think this could be cleaned up like this:
--- a/drivers/xen/blktap/ring.c
+++ b/drivers/xen/blktap/ring.c
@@ -8,7 +8,6 @@
#include "blktap.h"
int blktap_ring_major;
-static struct cdev blktap_ring_cdev;
/*
* BLKTAP - immediately before the mmap area,
@@ -511,26 +510,16 @@ blktap_ring_debug(struct blktap *tap, ch
int __init
blktap_ring_init(void)
{
- dev_t dev = 0;
int err;
- cdev_init(&blktap_ring_cdev, &blktap_ring_file_operations);
- blktap_ring_cdev.owner = THIS_MODULE;
-
- err = alloc_chrdev_region(&dev, 0, MAX_BLKTAP_DEVICE, "blktap2");
+ err = __register_chrdev(0, 0, MAX_BLKTAP_DEVICE, "blktap2",
+ &blktap_ring_file_operations);
if (err < 0) {
BTERR("error registering ring devices: %d\n", err);
return err;
}
- err = cdev_add(&blktap_ring_cdev, dev, MAX_BLKTAP_DEVICE);
- if (err) {
- BTERR("error adding ring device: %d\n", err);
- unregister_chrdev_region(dev, MAX_BLKTAP_DEVICE);
- return err;
- }
-
- blktap_ring_major = MAJOR(dev);
+ blktap_ring_major = err;
BTINFO("blktap ring major: %d\n", blktap_ring_major);
return 0;
@@ -542,9 +531,8 @@ blktap_ring_exit(void)
if (!blktap_ring_major)
return;
- cdev_del(&blktap_ring_cdev);
- unregister_chrdev_region(MKDEV(blktap_ring_major, 0),
- MAX_BLKTAP_DEVICE);
+ __unregister_chrdev(blktap_ring_major, 0, MAX_BLKTAP_DEVICE,
+ "blktap2");
blktap_ring_major = 0;
}
And probably converting MAX_BLKTAP_DEVICE into a configure
option would also be reasonable.
In any case, if I wanted to formally submit patches to clean up
this and some other things in the pv-ops variant, what (preferably
non-topic) branch should those be against? If I'm not mistaken,
xen/next-2.6.38 for example doesn't even have a blktap - or did
it get moved out of drivers/xen/? And what would be the most
up-to-date non-experimental branch to pull blktap bits from?
Jan
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