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powerpc/powernv/ioda: Remove explicit max window size check 

DMA windows can only have a size of power of two on IODA2 hardware and
using memory_hotplug_max() to determine the upper limit won't work
correcly if it returns not power of two value.

This removes the check as the platform code does this check in
pnv_pci_ioda2_setup_default_config() anyway; the other client is VFIO
and that thing checks against locked_vm limit which prevents the userspace
from locking too much memory.

It is expected to impact DPDK on machines with non-power-of-two RAM size,
mostly. KVM guests are less likely to be affected as usually guests get
less than half of hosts RAM.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy 2017-11-07 14:43:01 +11:00 committed by Michael Ellerman
parent cd77b5ce20
commit 9003a24981
1 changed files with 1 additions and 1 deletions
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2
arch/powerpc/platforms/powernv/pci-ioda.c
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@ -2797,7 +2797,7 @@ static long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset,
if (!levels || (levels > POWERNV_IOMMU_MAX_LEVELS))
return -EINVAL;
if ((window_size > memory_hotplug_max()) || !is_power_of_2(window_size))
if (!is_power_of_2(window_size))
return -EINVAL;
/* Adjust direct table size from window_size and levels */