net/mlx4_core: Fix SRIOV free-pool management when enforcing resource quotas
The Hypervisor driver tracks free slots and reserved slots at the global level and tracks allocated slots and guaranteed slots per VF. Guaranteed slots are treated as reserved by the driver, so the total reserved slots is the sum of all guaranteed slots over all the VFs. As VFs allocate resources, free (global) is decremented and allocated (per VF) is incremented for those resources. However, reserved (global) is never changed. This means that effectively, when a VF allocates a resource from its guaranteed pool, it is actually reducing that resource's free pool (since the global reserved count was not also reduced). The fix for this problem is the following: For each resource, as long as a VF's allocated count is <= its guaranteed number, when allocating for that VF, the reserved count (global) should be reduced by the allocation as well. When the global reserved count reaches zero, the remaining global free count is still accessible as the free pool for that resource. When the VF frees resources, the reverse happens: the global reserved count for a resource is incremented only once the VFs allocated number falls below its guaranteed number. This fix was developed by Rick Kready <kready@us.ibm.com> Reported-by: NRick Kready <kready@us.ibm.com> Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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