[Devel] Re: [patch 12/38][IPV6] ip6_fib - move the fib table to the network namespace

[Brian Haley]

Hi Daniel,

Daniel Lezcano wrote:
> Move the global definition of the fib table to the network namespace
> structure and make their access to the initial network namespace.
....
> -void __init fib6_init(void)
> +static int fib6_net_init(struct net *net)
>  {
> -	fib6_node_kmem = kmem_cache_create("fib6_nodes",
> -					   sizeof(struct fib6_node),
> -					   0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
> -					   NULL);
> +	int ret;
>  
> -	fib_table_hash = kzalloc(sizeof(*fib_table_hash)*FIB_TABLE_HASHSZ, GFP_KERNEL);
> -	if (!fib_table_hash)
> -		panic("IPV6: Failed to allocate fib_table_hash.\n");
> -
> -	fib6_main_tbl = kzalloc(sizeof(*fib6_main_tbl), GFP_KERNEL);
> -	if (!fib6_main_tbl)
> -		panic("IPV6: Failed to allocate fib6_main_tbl.\n");
> -
> -	fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
> -	fib6_main_tbl->tb6_root.leaf = &ip6_null_entry;
> -	fib6_main_tbl->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
> +	if (net != &init_net)
> +		return -EPERM;
> +
> +	ret = -ENOMEM;
> +	net->fib_table_hash = kzalloc(sizeof(*net->fib_table_hash)*FIB_TABLE_HASHSZ,
> +				      GFP_KERNEL);
> +	if (!net->fib_table_hash)
> +		goto out;

So originally, the fib_table_hash was global with no allocation 
necessary.  Then in patch 11 you changed it to be dynamic and panic() on 
failure.  Now it just gracefully returns.  Do you really want to do that 
for the init_net namespace?  Won't the next routine that tries to access 
this NULL pointer oops?  Same for fib6_main_table, fib6_local_table, 
fib6_stats, etc.  Or did I miss where the callers error-out on an ENOMEM?

-Brian
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