Re: [PATCH v5 1/3] PCI: Fix off by one in dma_alias_mask allocation size

From: Christoph Hellwig
Date: Mon Dec 02 2019 - 12:03:08 EST


On Fri, Nov 29, 2019 at 05:56:19PM +0000, James Sewart wrote:
> The number of possible devfns is 256 so the size of the bitmap for
> allocations should be U8_MAX+1.
>
> Signed-off-by: James Sewart <jamessewart@xxxxxxxxxx>
> ---
> drivers/pci/pci.c | 2 +-
> drivers/pci/search.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index a97e2571a527..0a4449a30ace 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -5876,7 +5876,7 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode,
> void pci_add_dma_alias(struct pci_dev *dev, u8 devfn)
> {
> if (!dev->dma_alias_mask)
> - dev->dma_alias_mask = bitmap_zalloc(U8_MAX, GFP_KERNEL);
> + dev->dma_alias_mask = bitmap_zalloc(U8_MAX+1, GFP_KERNEL);

Missing whitespaces around the "+".

> - for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) {
> + for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX+1) {

Same here.