crypto: iaa - fall back to software for multi-entry scatterlists

IAA cannot process source or destination scatterlists with more than one
entry directly. Instead of failing these requests, route them through a
separate deflate acomp transform and keep the request alive in software.

The IAA driver has never handled multi-entry scatterlists, but the
limitation was latent until commit e2c3b6b21c77 ("mm: zswap: use SG list
decompression APIs from zsmalloc") made zswap pass the raw zsmalloc SG
list directly to crypto drivers, so objects spanning multiple pages now
reach IAA as multi-entry sources and would otherwise fail decompression.

Fallback to the generic DEFLATE implementation for scatterlists with
more than one entry. After the multi-entry cases fall back early,
simplify the DMA mapping path to a single scatterlist entry and fall
back on mapping failure as well.

Add counters to track the number of requests processed by the software
implementation on the compression direction.

Fixes: 2ec6761df889 ("crypto: iaa - Add support for deflate-iaa compression algorithm")
Fixes: e2c3b6b21c77 ("mm: zswap: use SG list decompression APIs from zsmalloc")
Cc: stable@vger.kernel.org
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

0 files changed, 0 insertions, 0 deletions