docs/core-api: memory-allocation: add mention of kmem_cache_create_userspace

Mention that when a part of a slab cache might be exported to the
userspace, the cache should be created using kmem_cache_create_usercopy()

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Mike Rapoport 2019-01-14 13:47:34 +02:00 committed by Jonathan Corbet
parent 58f4df3c1b
commit 98e5f349c9

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@ -113,9 +113,11 @@ see :c:func:`kvmalloc_node` reference documentation. Note that
If you need to allocate many identical objects you can use the slab
cache allocator. The cache should be set up with
:c:func:`kmem_cache_create` before it can be used. Afterwards
:c:func:`kmem_cache_alloc` and its convenience wrappers can allocate
memory from that cache.
:c:func:`kmem_cache_create` or :c:func:`kmem_cache_create_usercopy`
before it can be used. The second function should be used if a part of
the cache might be copied to the userspace. After the cache is
created :c:func:`kmem_cache_alloc` and its convenience wrappers can
allocate memory from that cache.
When the allocated memory is no longer needed it must be freed. You
can use :c:func:`kvfree` for the memory allocated with `kmalloc`,