Re: [PATCH bpf-next v4 1/6] vmalloc: introduce execmem_alloc, execmem_free, and execmem_fill

[Song Liu <song@kernel.org>]

On Mon, Nov 21, 2022 at 7:52 AM Daniel Borkmann <daniel@iogearbox.net> wrote:

[...]

> > + */
> > +void *execmem_alloc(unsigned long size, unsigned long align)
> > +{
> > +     struct vmap_area *va, *tmp;
> > +     unsigned long addr;
> > +     enum fit_type type;
> > +     int ret;
> > +
> > +     va = kmem_cache_alloc_node(vmap_area_cachep, GFP_KERNEL, NUMA_NO_NODE);
> > +     if (unlikely(!va))
> > +             return NULL;
> > +
> > +again:
> > +     preload_this_cpu_lock(&free_text_area_lock, GFP_KERNEL, NUMA_NO_NODE);
> > +     tmp = find_vmap_lowest_match(&free_text_area_root, size, align, 1, false);
> > +
> > +     if (!tmp) {
> > +             unsigned long alloc_size;
> > +             void *ptr;
> > +
> > +             spin_unlock(&free_text_area_lock);
> > +
> > +             /*
> > +              * Not enough continuous space in free_text_area_root, try
> > +              * allocate more memory. The memory is first added to
> > +              * vmap_area_root, and then moved to free_text_area_root.
> > +              */
> > +             alloc_size = roundup(size, PMD_SIZE * num_online_nodes());
> > +             ptr = __vmalloc_node_range(alloc_size, PMD_SIZE, EXEC_MEM_START,
> > +                                        EXEC_MEM_END, GFP_KERNEL, PAGE_KERNEL,
> > +                                        VM_ALLOW_HUGE_VMAP | VM_NO_GUARD,
> > +                                        NUMA_NO_NODE, __builtin_return_address(0));
> > +             if (unlikely(!ptr))
> > +                     goto err_out;
> > +
> > +             move_vmap_to_free_text_tree(ptr);
> > +             goto again;
> > +     }
> > +
> > +     addr = roundup(tmp->va_start, align);
> > +     type = classify_va_fit_type(tmp, addr, size);
> > +     if (WARN_ON_ONCE(type == NOTHING_FIT))
> > +             goto err_out_unlock;
>
> Isn't this already covered in adjust_va_to_fit_type()?

That's right! Now we can get rid of err_out_unlock. Thanks!

Also fixed other nits.

Song

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