Re: [PATCH v6 1/3] PCI: Fix off by one in dma_alias_mask allocation size

Bjorn Helgaas
2019-12-10T22:41:21Z

[+cc Joerg]

On Tue, Dec 03, 2019 at 03:43:22PM +0000, James Sewart wrote:
> The number of possible devfns is 256, add def and correct uses.
>
> Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
> Signed-off-by: James Sewart <jamessewart@arista.com>

I applied these three patches to pci/virtualization for v5.6, thanks!

I moved the MAX_NR_DEVFNS from include/linux/pci.h to
drivers/pci/pci.h since nobody outside drivers/pci needs it.

> ---
> drivers/pci/pci.c | 2 +-
> drivers/pci/search.c | 2 +-
> include/linux/pci.h | 2 ++
> 3 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index a97e2571a527..d3c83248f3ce 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(MAX_NR_DEVFNS, GFP_KERNEL);
> if (!dev->dma_alias_mask) {
> pci_warn(dev, "Unable to allocate DMA alias mask\n");
> return;
> diff --git a/drivers/pci/search.c b/drivers/pci/search.c
> index bade14002fd8..9e4dfae47252 100644
> --- a/drivers/pci/search.c
> +++ b/drivers/pci/search.c
> @@ -43,7 +43,7 @@ int pci_for_each_dma_alias(struct pci_dev *pdev,
> if (unlikely(pdev->dma_alias_mask)) {
> u8 devfn;
>
> - for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) {
> + for_each_set_bit(devfn, pdev->dma_alias_mask, MAX_NR_DEVFNS) {
> ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn),
> data);
> if (ret)
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 1a6cf19eac2d..6481da29d667 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -57,6 +57,8 @@
> #define PCI_DEVID(bus, devfn) ((((u16)(bus)) << 8) | (devfn))
> /* return bus from PCI devid = ((u16)bus_number) << 8) | devfn */
> #define PCI_BUS_NUM(x) (((x) >> 8) & 0xff)
> +/* Number of possible devfns. devfns can be from 0.0 to 1f.7 inclusive */
> +#define MAX_NR_DEVFNS 256
>
> /* pci_slot represents a physical slot */
> struct pci_slot {
> --
> 2.24.0
>
>