crypto: qat - change SLAs cleanup flow at shutdown

The implementation of the Rate Limiting (RL) feature includes the cleanup
of all SLAs during device shutdown. For each SLA, the firmware is notified
of the removal through an admin message, the data structures that take
into account the budgets are updated and the memory is freed.
However, this explicit cleanup is not necessary as (1) the device is
reset, and the firmware state is lost and (2) all RL data structures
are freed anyway.

In addition, if the device is unresponsive, for example after a PCI
AER error is detected, the admin interface might not be available.
This might slow down the shutdown sequence and cause a timeout in
the recovery flows which in turn makes the driver believe that the
device is not recoverable.

Fix by replacing the explicit SLAs removal with just a free of the
SLA data structures.

Fixes: d9fb8408376e ("crypto: qat - add rate limiting feature to qat_4xxx")
Cc: <stable@vger.kernel.org>
Signed-off-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: qat - fix mutex ordering in adf_rl

If the function validate_user_input() returns an error, the error path
attempts to unlock an unacquired mutex.
Acquire the mutex before calling validate_user_input(). This is not
strictly necessary but simplifies the code.

Fixes: d9fb8408376e ("crypto: qat - add rate limiting feature to qat_4xxx")
Signed-off-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: qat - fix error path in add_update_sla()

The input argument `sla_in` is a pointer to a structure that contains
the parameters of the SLA which is being added or updated.
If this pointer is NULL, the function should return an error as
the data required for the algorithm is not available.
By mistake, the logic jumps to the error path which dereferences
the pointer.

This results in a warnings reported by the static analyzer Smatch when
executed without a database:

drivers/crypto/intel/qat/qat_common/adf_rl.c:871 add_update_sla()
error: we previously assumed 'sla_in' could be null (see line 812)

This issue was not found in internal testing as the pointer cannot be
NULL. The function add_update_sla() is only called (indirectly) by
the rate limiting sysfs interface implementation in adf_sysfs_rl.c
which ensures that the data structure is allocated and valid. This is
also proven by the fact that Smatch executed with a database does not
report such error.

Fix it by returning with error if the pointer `sla_in` is NULL.

Fixes: d9fb8408376e ("crypto: qat - add rate limiting feature to qat_4xxx")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: qat - add rate limiting sysfs interface

Add an interface for the rate limiting feature which allows to add,
remove and modify a QAT SLA (Service Level Agreement).

This adds a new sysfs attribute group, `qat_rl`, which can be accessed
from /sys/bus/pci/devices/<BUS:DEV:FUNCTION> with the following
hierarchy:
|-+ qat_rl
|---- id (RW) # SLA identifier
|---- cir (RW) # Committed Information Rate
|---- pir (RW) # Peak Information Rate
|---- srv (RW) # Service to be rate limited
|---- rp (RW) (HEX) # Ring pairs to be rate limited
|---- cap_rem (RW) # Remaining capability for a service
|---- sla_op (WO) # Allows to perform an operation on an SLA

The API works by setting the appropriate RW attributes and then
issuing a command through the `sla_op`. For example, to create an SLA, a
user needs to input the necessary data into the attributes cir, pir, srv
and rp and then write into `sla_op` the command `add` to execute the
operation.
The API also provides `cap_rem` attribute to get information about
the remaining device capability within a certain service which is
required when setting an SLA.

Signed-off-by: Ciunas Bennett <ciunas.bennett@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Tero Kristo <tero.kristo@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: qat - add rate limiting feature to qat_4xxx

The Rate Limiting (RL) feature allows to control the rate of requests
that can be submitted on a ring pair (RP). This allows sharing a QAT
device among multiple users while ensuring a guaranteed throughput.

The driver provides a mechanism that allows users to set policies, that
are programmed to the device. The device is then enforcing those policies.

Configuration of RL is accomplished through entities called SLAs
(Service Level Agreement). Each SLA object gets a unique identifier
and defines the limitations for a single service across up to four
ring pairs (RPs count allocated to a single VF).

The rate is determined using two fields:
* CIR (Committed Information Rate), i.e., the guaranteed rate.
* PIR (Peak Information Rate), i.e., the maximum rate achievable
when the device has available resources.
The rate values are expressed in permille scale i.e. 0-1000.
Ring pair selection is achieved by providing a 64-bit mask, where
each bit corresponds to one of the ring pairs.

This adds an interface and logic that allow to add, update, retrieve
and remove an SLA.

Signed-off-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Tero Kristo <tero.kristo@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>