[ENBD] 2.5.46 update

[Tad Kollar]

> Can you observe the growth with time or requests of this figure?

After rebooting and restarting the clients and lvm, the size of the module is 
116k and holding steady, even after a large copy. Maybe it was the lvm 
pvcreate process or format that aggravated it before, or else time is a 
factor... it was up for about 24 hours. There weren't any noticable effects of 
the huge module 'size'.

> I can take out the statics in the driver and put them under kmalloc
> control.  I have a patch for that.  I did it to the 2.4 driver and it
> cut the apparent size in half (from 100K+ to 50K).

Sounds good...

I tried merge_requests=30 and got a hard lockup during sync after a 213M copy 
operation. Not 100% sure merge_requests was the cause, but without that option 
the copy and sync succeeded on a second try. Performance seems okay... I guess 
I'll try a bonnie run.

Tad