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>

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 7e87867984e72b9463c815a9dfb96d584716c95c..749055553064041369d111b01b793ba9368a5d48 100644 (file)
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -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 */