Commit 39ab773e authored by Wei Fang's avatar Wei Fang Committed by Jakub Kicinski
Browse files

net: enetc: fix the off-by-one issue in enetc_map_tx_buffs() 



When a DMA mapping error occurs while processing skb frags, it will free
one more tx_swbd than expected, so fix this off-by-one issue.

Fixes: d4fd0404 ("enetc: Introduce basic PF and VF ENETC ethernet drivers")
Cc: stable@vger.kernel.org
Suggested-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Suggested-by: default avatarMichal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: default avatarWei Fang <wei.fang@nxp.com>
Reviewed-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: default avatarClaudiu Manoil <claudiu.manoil@nxp.com>
Link: https://patch.msgid.link/20250224111251.1061098-2-wei.fang@nxp.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 85c7ca91

drivers/net/ethernet/freescale/enetc/enetc.c

+19 −7
Original line number Diff line number Diff line
@@ -167,6 +167,24 @@ static bool enetc_skb_is_tcp(struct sk_buff *skb) 
	return skb->csum_offset == offsetof(struct tcphdr, check);

}



/**

 * enetc_unwind_tx_frame() - Unwind the DMA mappings of a multi-buffer Tx frame

 * @tx_ring: Pointer to the Tx ring on which the buffer descriptors are located

 * @count: Number of Tx buffer descriptors which need to be unmapped

 * @i: Index of the last successfully mapped Tx buffer descriptor

 */

static void enetc_unwind_tx_frame(struct enetc_bdr *tx_ring, int count, int i)

{

	while (count--) {

		struct enetc_tx_swbd *tx_swbd = &tx_ring->tx_swbd[i];



		enetc_free_tx_frame(tx_ring, tx_swbd);

		if (i == 0)

			i = tx_ring->bd_count;

		i--;

	}

}



static int enetc_map_tx_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb)

{

	bool do_vlan, do_onestep_tstamp = false, do_twostep_tstamp = false;
@@ -372,13 +390,7 @@ static int enetc_map_tx_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb) 
dma_err:

	dev_err(tx_ring->dev, "DMA map error");



	do {

		tx_swbd = &tx_ring->tx_swbd[i];

		enetc_free_tx_frame(tx_ring, tx_swbd);

		if (i == 0)

			i = tx_ring->bd_count;

		i--;

	} while (count--);

	enetc_unwind_tx_frame(tx_ring, count, i);



	return 0;

}