On 3 June 2016 at 18:09, Herbert Xu [off-list ref] wrote:

On Fri, Jun 03, 2016 at 05:23:59PM +0800, Baolin Wang wrote:

quoted

Assuming one 64K size bio coming, we can map the whole bio with one sg
table in crypt_convert_bulk_block() function. But if we send this bulk
request to crypto layer, we should divide the bulk request into small
requests, and each small request should be one sector size (512 bytes)
with assuming the correct IV, but we need to allocate small requests
memory for the division, which will not good for IO mapping, and how
each small request connect to dm-crypt (how to notify the request is
done?)?

Why won't it be good? The actual AES block size is 16 and yet we

Like I said, we should avoid memory allocation to improve efficiency
in the IO path. Another hand is how the divided small requests
(allocate request memory at crypt layer) connect with dm-crypt? Since
dm-crypt just send one bulk request to crypt layer, but it will be
divided into small requests at crypt layer.

have no trouble when you feed it a block of 512 bytes.

That's right.

-- 
Baolin.wang
Best Regards