dm crypt: don't allocate pages for a partial request

Change crypt_alloc_buffer so that it only ever allocates pages for a
full request.  This is a prerequisite for the commit "dm crypt: offload
writes to thread".

This change simplifies the dm-crypt code at the expense of reduced
throughput in low memory conditions (where allocation for a partial
request is most useful).

Note: the next commit ("dm crypt: avoid deadlock in mempools") is needed
to fix a theoretical deadlock.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
(cherry picked from commit cf2f1abfbd0dba701f7f16ef619e4d2485de3366)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

0 files changed, 0 insertions, 0 deletions