[PATCH] fscrypt: Factor out bio specific functions

[Christoph Hellwig]

On Fri, Dec 16, 2016 at 02:14:28PM -0800, Eric Biggers wrote:
> Hmm, it still seems weird to define fscrypt_zeroout_range() when it can't
> actually be used.  It looks like the problem is specifically the use of
> alloc_bounce_page() and do_page_crypto().  Would it be that bad to make those
> available in fscrypt_internal.h (not exported to filesystems)?

Sounds good to me.

> Also, it seems the actual problem is that fscrypt_zeroout_range() tries to be
> clever and reuse one bounce page over and over.  But this seems very inefficient
> because it has to wait for each block to be synchronously written out before
> moving on to the next.  I'm thinking it really should be updated to work more
> like the normal write path, and then it could use fscrypt_encrypt_page()...

That sounds even better, but might take a little more time.