Commit 512d1999 authored by Ivan Malov's avatar Ivan Malov Committed by Daniel Borkmann
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xsk: Clear page contiguity bit when unmapping pool 



When a XSK pool gets mapped, xp_check_dma_contiguity() adds bit 0x1
to pages' DMA addresses that go in ascending order and at 4K stride.

The problem is that the bit does not get cleared before doing unmap.
As a result, a lot of warnings from iommu_dma_unmap_page() are seen
in dmesg, which indicates that lookups by iommu_iova_to_phys() fail.

Fixes: 2b43470a ("xsk: Introduce AF_XDP buffer allocation API")
Signed-off-by: default avatarIvan Malov <ivan.malov@oktetlabs.ru>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220628091848.534803-1-ivan.malov@oktetlabs.ru
parent 32df6fe1

net/xdp/xsk_buff_pool.c

+1 −0
Original line number Diff line number Diff line
@@ -332,6 +332,7 @@ static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs) 
	for (i = 0; i < dma_map->dma_pages_cnt; i++) {

		dma = &dma_map->dma_pages[i];

		if (*dma) {

			*dma &= ~XSK_NEXT_PG_CONTIG_MASK;

			dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,

					     DMA_BIDIRECTIONAL, attrs);

			*dma = 0;