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

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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 e2c3b6b21c ("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: 2ec6761df8 ("crypto: iaa - Add support for deflate-iaa compression algorithm")
Fixes: e2c3b6b21c ("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>

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This commit is contained in:

Giovanni Cabiddu 2026-08-05 14:19:23 -07:00 • committed by Herbert Xu

parent b1c0e12097

commit c7fdfd2bee

3 changed files with 71 additions and 51 deletions

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111

drivers/crypto/intel/iaa/iaa_crypto_main.c

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9

drivers/crypto/intel/iaa/iaa_crypto_stats.c

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2

drivers/crypto/intel/iaa/iaa_crypto_stats.h

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