[Unionfs] INgo Molnar's RT patch

[Paul Hewlett]

Hi Erez

I like to live dangerously so I am experimenting with Ingo Molnar's RT patch 
for linux. 

I am using Gentoo kernel 2.6.21-gentoo-r4. I applied linux-2.6.21.5-u1.diff.gz 
patch for unionfs - this applied cleanly with some minor mods to the 
Makefile. I then applied the patch-2.6.21.6-rt21 from Ingo Molnar's site - I 
had to do some hand-hacking. 

When I compiled, the file fs/unionfs/inode.c failed. A 
structure 'rw_semaphore' was being used and this did not now exist. I 
discovered that if I changed the declaration of rwsem in union.h at line 146 
in the declaration of struct unionfs_sb_info from

      struct rw_semaphore rwsem;

to 

      struct compat_rw_semaphore rwsem;

then everything compiled.

Hope this info is helpful. Is there any test scenario with this that you would 
like me to try ?

 The kernel boots quite happily and I have also enabled the nvidia drivers - 
in fact I am sending this email from the PC in question.

Regards Paul 
-- 
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