[PATCH v2 1/6] ntb: Store original DMA address for future release

Leon Romanovsky
2026-05-01T06:35:39Z

The DMA API requires that dma_free_attrs receive the exact dma_handle
originally returned by the allocation function. Do not modify it.

Fixes: fc5d1829f9bf ("NTB: transport: Try harder to alloc an aligned MW buffer")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
drivers/ntb/ntb_transport.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 7cabc82305d6b..771eb7d9f4356 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -223,6 +223,7 @@ struct ntb_transport_mw {
void *alloc_addr;
void *virt_addr;
dma_addr_t dma_addr;
+ dma_addr_t original_dma_addr;
};

struct ntb_transport_client_dev {
@@ -766,7 +767,7 @@ static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)

ntb_mw_clear_trans(nt->ndev, PIDX, num_mw);
dma_free_coherent(dma_dev, mw->alloc_size,
- mw->alloc_addr, mw->dma_addr);
+ mw->alloc_addr, mw->original_dma_addr);
mw->xlat_size = 0;
mw->buff_size = 0;
mw->alloc_size = 0;
@@ -802,6 +803,7 @@ static int ntb_alloc_mw_buffer(struct ntb_transport_mw *mw,
return -ENOMEM;
}
virt_addr = alloc_addr;
+ mw->original_dma_addr = dma_addr;

/*
* we must ensure that the memory address allocated is BAR size

--
2.53.0