On Sat, Dec 12, 2020 at 08:13:54PM +0100, Marek Vasut wrote: > On 12/10/20 7:11 PM, Lorenzo Pieralisi wrote: > > [...] > > > > diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c > > > index 1194d5f3341b..ac5c7d7573a6 100644 > > > --- a/drivers/pci/controller/pcie-rcar-host.c > > > +++ b/drivers/pci/controller/pcie-rcar-host.c > > > @@ -753,7 +753,7 @@ static int rcar_pcie_enable_msi(struct rcar_pcie_host *host) > > > } > > > /* setup MSI data target */ > > > - msi->pages = __get_free_pages(GFP_KERNEL, 0); > > > + msi->pages = __get_free_pages(GFP_KERNEL | GFP_DMA32, 0); > > > > This does not do what you want on !CONFIG_ZONE_DMA32 (ie arm LPAE). > > How come? I would expect GFP_DMA32 allocates a buffer below 4 GiB in any > case. For ARM LPAE allocation falls back to ZONE_NORMAL that happens to work because if there is memory > 4GB it ends up in ZONE_HIGHMEM, so this patch should still work on ARM LPAE too. Regardless, thoughts above the alternative approach (that saves you a page allocation) ? Lorenzo
