On Thu, Nov 06, 2014 at 10:32:18PM +0800, Herbert Xu wrote:

On Thu, Nov 06, 2014 at 03:26:33PM +0100, Maxime Ripard wrote:

quoted

But you still haven't explain why the driver, while it doesn't handle
the user space buffer at any time, should be worried that the data the
framework has given him are actually mapped.

Encryption is used by IPsec and SKBs can be allocated in highmem.
algif also exposes all ciphers to user-space memory which can also
be in highmem.

Ok. We keep going in circles here.

I know that algif handles userspace memory that can be in
highmem. What I don't get, is that just like a *driver* doesn't have
to call copy_from_user, why would it need to call kmap...

That's something that should be in the framework itself, not the
driver. And the argument that most drivers use DMA seems like a broken
assumption.

But hey, you're the one that will maintain this mess, so I guess you
have the final word.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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