Commit 807c2743 authored by Niklas Schnelle's avatar Niklas Schnelle Committed by Vasily Gorbik
Browse files

s390/pci: Fix dev.dma_range_map missing sentinel element 



The fixed commit sets up dev.dma_range_map but missed that this is
supposed to be an array of struct bus_dma_region with a sentinel element
with the size field set to 0 at the end. This would lead to overruns in
e.g. dma_range_map_min(). It could also result in wrong translations
instead of DMA_MAPPING_ERROR in translate_phys_to_dma() if the paddr
were to not fit in the aperture. Fix this by using the
dma_direct_set_offset() helper which creates a sentinel for us.

Fixes: d236843a ("s390/pci: store DMA offset in bus_dma_region")
Reviewed-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: default avatarNiklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20250312-fix_dma_map_alloc-v2-1-530108d9de21@linux.ibm.com


Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent af6bfcd1

arch/s390/pci/pci_bus.c

+11 −13
Original line number Diff line number Diff line
@@ -287,23 +287,21 @@ static struct zpci_bus *zpci_bus_alloc(int topo, bool topo_is_tid) 
static void pci_dma_range_setup(struct pci_dev *pdev)

{

	struct zpci_dev *zdev = to_zpci(pdev);

	struct bus_dma_region *map;

	u64 aligned_end;

	u64 aligned_end, size;

	dma_addr_t dma_start;

	int ret;



	map = kzalloc(sizeof(*map), GFP_KERNEL);

	if (!map)

		return;



	map->cpu_start = 0;

	map->dma_start = PAGE_ALIGN(zdev->start_dma);

	dma_start = PAGE_ALIGN(zdev->start_dma);

	aligned_end = PAGE_ALIGN_DOWN(zdev->end_dma + 1);

	if (aligned_end >= map->dma_start)

		map->size = aligned_end - map->dma_start;

	if (aligned_end >= dma_start)

		size = aligned_end - dma_start;

	else

		map->size = 0;

	WARN_ON_ONCE(map->size == 0);

		size = 0;

	WARN_ON_ONCE(size == 0);



	pdev->dev.dma_range_map = map;

	ret = dma_direct_set_offset(&pdev->dev, 0, dma_start, size);

	if (ret)

		pr_err("Failed to allocate DMA range map for %s\n", pci_name(pdev));

}



void pcibios_bus_add_device(struct pci_dev *pdev)