Hi,
> > #define kfree_rcu(data, rcuhead) do { \
> > void __kfree_rcu_fn(struct rcu_head *rcu_head) \
> > { \
> > void *___ptr; \
> > ___ptr = container_of(rcu_head, typeof(*(data)), rcuhead);\
> > kfree(___ptr); \
> > } \
> > call_rcu(&(data)->rcuhead, __kfree_rcu_fn); \
> > } while (0)
> >
> >
> > This works, thanks to gcc supporting nested functions, but has one major
> > issue: any module using call_rcu() must have an rcu_barrier() in its
> > module_exit() because __kfree_rcu_fn() might be called after the module
> > is unloaded. For kfree_rcu() this isn't needed since the function called
> > lives in the base kernel.
>
> This looks nice to me.
:-)
> > I played around with injecting a call to rcu_barrier() into module exit
> > by modifying module_exit() but I couldn't make the CPP do that. Anyone
> > else have any ideas?
>
> I played around with module_exit and modified the define into the
> following. Now rcu_barrier() gets called on every module_exit. As
> modules are not unloaded so often it should not hurd that this is also
> done when unloading a module not using kfree_rcu().
Ok.
> #undef module_exit
> #define module_exit(exitfn) \
> void __exit __exit_rcu_barrier(void) \
> { \
> exitfn(); \
> rcu_barrier(); \
> } \
> static inline exitcall_t __exittest(void) \
> { return exitfn; } \
> void cleanup_module(void) __attribute__((alias("__exit_rcu_barrier")));
> Johannes are you fine with this?
Frankly, I don't think I really understand it, but if it works, why not?
I guess I could stick a printk into that function there to verify it ;-)
johannes
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