On Sat, Dec 30, 2023 at 11:58:29AM +0000, Greg Kroah-Hartman wrote:
> 6.6-stable review patch. If anyone has any objections, please let me know.
>
No objections from me.
For reference I do have an implementation of this functionality to v6.1
if/when it should be added. It is different as the bnxt_en driver did
not use the page pool to manage DMA mapping until v6.6.
The minimally disruptive patch to prevent this memory leak is below:
>From dc82f8b57e2692ec987628b53e6446ab9f4fa615 Mon Sep 17 00:00:00 2001
From: Andy Gospodarek <andrew.gospodarek@xxxxxxxxxxxx>
Date: Thu, 7 Dec 2023 16:23:21 -0500
Subject: [PATCH] bnxt_en: unmap frag buffers before returning page to pool
If pages are not unmapped before calling page_pool_recycle_direct they
will not be freed back to the pool. This will lead to a memory leak and
messages like the following in dmesg:
[ 8229.436920] page_pool_release_retry() stalled pool shutdown 340 inflight 5437 sec
Fixes: a7559bc8c17c ("bnxt: support transmit and free of aggregation buffers")
Signed-off-by: Andy Gospodarek <andrew.gospodarek@xxxxxxxxxxxx>
---
drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
index aa56db138d6b..5b4548fad870 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -80,6 +80,7 @@ struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
return NULL;
dma_unmap_addr_set(frag_tx_buf, mapping, frag_mapping);
+ dma_unmap_addr_set(frag_tx_buf, len, frag_len);
flags = frag_len << TX_BD_LEN_SHIFT;
txbd->tx_bd_len_flags_type = cpu_to_le32(flags);
@@ -154,8 +155,14 @@ void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts)
frags = tx_buf->nr_frags;
for (j = 0; j < frags; j++) {
+ struct pci_dev *pdev = bp->pdev;
+
tx_cons = NEXT_TX(tx_cons);
tx_buf = &txr->tx_buf_ring[tx_cons];
+ dma_unmap_single(&pdev->dev,
+ dma_unmap_addr(tx_buf, mapping),
+ dma_unmap_len(tx_buf, len),
+ DMA_TO_DEVICE);
page_pool_recycle_direct(rxr->page_pool, tx_buf->page);
}
}
>
> From: Andy Gospodarek <andrew.gospodarek@xxxxxxxxxxxx>
>
> [ Upstream commit 23c93c3b6275a59f2a685f4a693944b53c31df4e ]
>
> Remove double-mapping of DMA buffers as it can prevent page pool entries
> from being freed. Mapping is managed by page pool infrastructure and
> was previously managed by the driver in __bnxt_alloc_rx_page before
> allowing the page pool infrastructure to manage it.
>
> Fixes: 578fcfd26e2a ("bnxt_en: Let the page pool manage the DMA mapping")
> Reviewed-by: Somnath Kotur <somnath.kotur@xxxxxxxxxxxx>
> Signed-off-by: Andy Gospodarek <andrew.gospodarek@xxxxxxxxxxxx>
> Signed-off-by: Michael Chan <michael.chan@xxxxxxxxxxxx>
> Reviewed-by: David Wei <dw@xxxxxxxxxxx>
> Link: https://lore.kernel.org/r/20231214213138.98095-1-michael.chan@xxxxxxxxxxxx
> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
> drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 11 ++---------
> 1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
> index 96f5ca778c67d..8cb9a99154aad 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
> @@ -59,7 +59,6 @@ struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
> for (i = 0; i < num_frags ; i++) {
> skb_frag_t *frag = &sinfo->frags[i];
> struct bnxt_sw_tx_bd *frag_tx_buf;
> - struct pci_dev *pdev = bp->pdev;
> dma_addr_t frag_mapping;
> int frag_len;
>
> @@ -73,16 +72,10 @@ struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
> txbd = &txr->tx_desc_ring[TX_RING(prod)][TX_IDX(prod)];
>
> frag_len = skb_frag_size(frag);
> - frag_mapping = skb_frag_dma_map(&pdev->dev, frag, 0,
> - frag_len, DMA_TO_DEVICE);
> -
> - if (unlikely(dma_mapping_error(&pdev->dev, frag_mapping)))
> - return NULL;
> -
> - dma_unmap_addr_set(frag_tx_buf, mapping, frag_mapping);
> -
> flags = frag_len << TX_BD_LEN_SHIFT;
> txbd->tx_bd_len_flags_type = cpu_to_le32(flags);
> + frag_mapping = page_pool_get_dma_addr(skb_frag_page(frag)) +
> + skb_frag_off(frag);
> txbd->tx_bd_haddr = cpu_to_le64(frag_mapping);
>
> len = frag_len;
> --
> 2.43.0
>
>
>
