On Tue, Sep 22, 2020 at 04:35:06PM +0200, Christoph Hellwig wrote: > > /** > > - * vfree - release memory allocated by vmalloc() > > - * @addr: memory base address > > + * vfree - Release memory allocated by vmalloc() > > + * @addr: Memory base address > > * > > * Free the virtually continuous memory area starting at @addr, as > > + * obtained from vmalloc(), vmalloc_32() or __vmalloc(). If called > > + * on an @addr obtained from vmap(), it will put one refcount on each > > + * mapped page, which will free the page if this is the last refcount > > + * on the page. If @addr is NULL, no operation is performed. > > This reads a little confusing. First it only allows vmalloc* and > then it mentions vmap in the next sentence. And what about > vmalloc_32_user, vzalloc_node, vmalloc_node, vmalloc_user, vzalloc and > __vmalloc_node? In my defence, I didn't write that sentence; you snipped: - * obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is - * NULL, no operation is performed. I don't think it makes sense to list all vmalloc-style allocators here. It won't be updated by people who add new variations. How about this? * Free the virtually continuous memory area starting at @addr, as * obtained from one of the vmalloc() family of APIs. This will * usually also free the physical memory underlying the virtual * allocation, but that memory is reference counted, so it will not * be freed until the last user goes away. * * If @addr is NULL, no operation is performed. I'm trying to strike a balance between being accurate and not requiring device driver authors to learn all about struct page. I may be too close to the implementation to write good documentation for it.
