This is a note to let you know that I've just added the patch titled
xsk: Clear page contiguity bit when unmapping pool
to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xsk-clear-page-contiguity-bit-when-unmapping-pool.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit af4f133aaa0dc158afe89c5be2e2f149afc1214f
Author: Ivan Malov <ivan.malov@xxxxxxxxxxxx>
Date: Tue Jun 28 12:18:48 2022 +0300
xsk: Clear page contiguity bit when unmapping pool
[ Upstream commit 512d1999b8e94a5d43fba3afc73e774849674742 ]
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: 2b43470add8c ("xsk: Introduce AF_XDP buffer allocation API")
Signed-off-by: Ivan Malov <ivan.malov@xxxxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
Link: https://lore.kernel.org/bpf/20220628091848.534803-1-ivan.malov@xxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 87bdd71c7bb6..f70112176b7c 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -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;
