[PATCH bpf-next 2/4] bpf: Make bpf inode storage available to tracing program

[Christian Brauner]

On Wed, Nov 13, 2024 at 02:15:20PM +0000, Song Liu wrote:
> Hi Christian, 
> 
> Thanks for your review. 
> 
> > On Nov 13, 2024, at 2:19 AM, Christian Brauner <brauner at kernel.org> wrote:
> [...]
> 
> >> diff --git a/include/linux/fs.h b/include/linux/fs.h
> >> index 3559446279c1..479097e4dd5b 100644
> >> --- a/include/linux/fs.h
> >> +++ b/include/linux/fs.h
> >> @@ -79,6 +79,7 @@ struct fs_context;
> >> struct fs_parameter_spec;
> >> struct fileattr;
> >> struct iomap_ops;
> >> +struct bpf_local_storage;
> >> 
> >> extern void __init inode_init(void);
> >> extern void __init inode_init_early(void);
> >> @@ -648,6 +649,9 @@ struct inode {
> >> #ifdef CONFIG_SECURITY
> >> void *i_security;
> >> #endif
> >> +#ifdef CONFIG_BPF_SYSCALL
> >> + struct bpf_local_storage __rcu *i_bpf_storage;
> >> +#endif
> > 
> > Sorry, we're not growing struct inode for this. It just keeps getting
> > bigger. Last cycle we freed up 8 bytes to shrink it and we're not going
> > to waste them on special-purpose stuff. We already NAKed someone else's
> > pet field here.
> 
> Would it be acceptable if we union i_bpf_storage with i_security?

I have no quarrels with this if this is acceptable to you.