Re: [PATCH v2 4/8] powerpc/mm: protect linear mapping modifications by a mutex

From: Oscar Salvador
Date: Tue Nov 17 2020 - 10:37:56 EST


On Wed, Nov 11, 2020 at 03:53:18PM +0100, David Hildenbrand wrote:
> @@ -144,7 +147,9 @@ void __ref arch_remove_linear_mapping(u64 start, u64 size)
> start = (unsigned long)__va(start);
> flush_dcache_range_chunked(start, start + size, FLUSH_CHUNK_SIZE);
>
> + mutex_lock(&linear_mapping_mutex);
> ret = remove_section_mapping(start, start + size);
> + mutex_unlock(&linear_mapping_mutex);
> WARN_ON_ONCE(ret);

My expertise in this area is low, so bear with me.

Why we do not need to protect flush_dcache_range_chunked and
vm_unmap_aliases?

--
Oscar Salvador
SUSE L3