The implementations of the crypto algorithms (aead, skcipher, etc) in
the QAT driver do not properly support requests with the
CRYPTO_TFM_REQ_MAY_BACKLOG flag set. If the HW queue is full, the driver
returns -EBUSY but does not enqueue the request. This can result in
applications like dm-crypt waiting indefinitely for the completion of a
request that was never submitted to the hardware.
Fix this by adding a software backlog queue: if the ring buffer is more
than eighty percent full, then the request is enqueued to a backlog
list and the error code -EBUSY is returned back to the caller.
Requests in the backlog queue are resubmitted at a later time, in the
context of the callback of a previously submitted request.
The request for which -EBUSY is returned is then marked as -EINPROGRESS
once submitted to the HW queues.
The submission loop inside the function qat_alg_send_message() has been
modified to decide which submission policy to use based on the request
flags. If the request does not have the CRYPTO_TFM_REQ_MAY_BACKLOG set,
the previous behaviour has been preserved.
Based on a patch by
Vishnu Das Ramachandran <vishnu.dasx.ramachandran@intel.com>
Cc: stable@vger.kernel.org
Fixes: d370cec321 ("crypto: qat - Intel(R) QAT crypto interface")
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Kyle Sanderson <kyle.leet@gmail.com>
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Marco Chiappero <marco.chiappero@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
All the algorithms in qat_algs.c and qat_asym_algs.c use the same
pattern to submit messages to the HW queues. Move the submission loop
to a new function, qat_alg_send_message(), and share it between the
symmetric and the asymmetric algorithms.
As part of this rework, since the number of retries before returning an
error is inconsistent between the symmetric and asymmetric
implementations, set it to a value that works for both (i.e. 20, was 10
in qat_algs.c and 100 in qat_asym_algs.c)
In addition fix the return code reported when the HW queues are full.
In that case return -ENOSPC instead of -EBUSY.
Including stable in CC since (1) the error code returned if the HW queues
are full is incorrect and (2) to facilitate the backport of the next fix
"crypto: qat - add backlog mechanism".
Cc: stable@vger.kernel.org
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Marco Chiappero <marco.chiappero@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
