PCI: Fix pci_add_dma_alias() bitmask size (f8bf2aeb) · Commits · 戴 / test

The number of possible devfns is 256, but pci_add_dma_alias() allocated a bitmap of size 255. Fix this off-by-one error. This fixes commits ("PCI: Add support for multiple DMA aliases") and ("PCI: Allocate dma_alias_mask with bitmap_zalloc()"), but I doubt it was possible to see a problem because it takes 4 64-bit longs (or 8 32-bit longs) to hold 255 bits, and bitmap_zalloc() doesn't save the 255-bit size anywhere. [bhelgaas: commit log, move #define to drivers/pci/pci.h, include loop limit fix from Qian Cai: https://lore.kernel.org/r/20191218170004.5297-1-cai@lca.pw ] Signed-off-by:

James Sewart <jamessewart@arista.com> Signed-off-by:

Bjorn Helgaas <bhelgaas@google.com> Reviewed-by:

Logan Gunthorpe <logang@deltatee.com>

drivers/pci/pci.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -6017,7 +6017,7 @@ EXPORT_SYMBOL_GPL(pci_pr3_present);
		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;

drivers/pci/pci.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -4,6 +4,9 @@

		#include <linux/pci.h>

		/* Number of possible devfns: 0.0 to 1f.7 inclusive */
		#define MAX_NR_DEVFNS 256

		#define PCI_FIND_CAP_TTL 48

		#define PCI_VSEC_ID_INTEL_TBT 0x1234 /* Thunderbolt */

drivers/pci/search.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -41,9 +41,9 @@ int pci_for_each_dma_alias(struct pci_dev *pdev,
		* DMA, iterate over that too.
		*/
		if (unlikely(pdev->dma_alias_mask)) {
		u8 devfn;
		unsigned int 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)

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