net/mlx5: Reuse DEKs after executing SYNC_CRYPTO command

net/mlx5: Reuse DEKs after executing SYNC_CRYPTO command

To fast update encryption keys, those freed keys with need_sync bit 1
and in_use bit 0 in a bulk, can be recycled. The keys are cached
internally by the NIC, so invalidating internal NIC caches by
SYNC_CRYPTO command is required before reusing them. A threshold in
driver is added to avoid invalidating for every update. Only when the
number of DEKs, which need to be synced, is over this threshold, the
sync process will start. Besides, it is done in system workqueue.

After SYNC_CRYPTO command is executed successfully, the bitmaps of
each bulk must be reset accordingly, so that the freed DEKs can be
reused. From the analysis in previous patch, the number of reused DEKs
can be calculated by hweight_long(need_sync XOR in_use), and the
need_sync bits can be reset by simply copying from in_use bits.

Two more list (avail_list and sync_list) are added for each pool. The
avail_list is for a bulk when all bits in need_sync are reset after
sync. If there is no avail deks, and all are be freed by users, the
bulk is moved to sync_list, instead of being destroyed in previous
patch, and waiting for the invalidation. While syncing, they are
simply reset need_sync bits, and moved to avail_list.

Besides, add a wait_for_free list for the to-be-free DEKs. It is to
avoid this corner case: when thread A is done with SYNC_CRYPTO but just
before starting to reset the bitmaps, thread B is alloc dek, and free
it immediately. It's obvious that this DEK can't be reused this time,
so put it to waiting list, and do free after bulk bitmaps reset is
finished.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>