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

James Sewart
2019-12-03T15:43:29Z

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>
---
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