Commit bf280c03 authored by Ilya Maximets's avatar Ilya Maximets Committed by Jeff Kirsher
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ixgbe: fix double clean of Tx descriptors with xdp 



Tx code doesn't clear the descriptors' status after cleaning.
So, if the budget is larger than number of used elems in a ring, some
descriptors will be accounted twice and xsk_umem_complete_tx will move
prod_tail far beyond the prod_head breaking the completion queue ring.

Fix that by limiting the number of descriptors to clean by the number
of used descriptors in the Tx ring.

'ixgbe_clean_xdp_tx_irq()' function refactored to look more like
'ixgbe_xsk_clean_tx_ring()' since we're allowed to directly use
'next_to_clean' and 'next_to_use' indexes.

CC: stable@vger.kernel.org
Fixes: 8221c5eb ("ixgbe: add AF_XDP zero-copy Tx support")
Signed-off-by: default avatarIlya Maximets <i.maximets@samsung.com>
Tested-by: default avatarWilliam Tu <u9012063@gmail.com>
Tested-by: default avatarEelco Chaudron <echaudro@redhat.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 377228ac

drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c

+11 −18
Original line number Diff line number Diff line
@@ -633,19 +633,17 @@ static void ixgbe_clean_xdp_tx_buffer(struct ixgbe_ring *tx_ring, 
bool ixgbe_clean_xdp_tx_irq(struct ixgbe_q_vector *q_vector,

			    struct ixgbe_ring *tx_ring, int napi_budget)

{

	u16 ntc = tx_ring->next_to_clean, ntu = tx_ring->next_to_use;

	unsigned int total_packets = 0, total_bytes = 0;

	u32 i = tx_ring->next_to_clean, xsk_frames = 0;

	unsigned int budget = q_vector->tx.work_limit;

	struct xdp_umem *umem = tx_ring->xsk_umem;

	union ixgbe_adv_tx_desc *tx_desc;

	struct ixgbe_tx_buffer *tx_bi;

	bool xmit_done;

	u32 xsk_frames = 0;



	tx_bi = &tx_ring->tx_buffer_info[i];

	tx_desc = IXGBE_TX_DESC(tx_ring, i);

	i -= tx_ring->count;

	tx_bi = &tx_ring->tx_buffer_info[ntc];

	tx_desc = IXGBE_TX_DESC(tx_ring, ntc);



	do {

	while (ntc != ntu) {

		if (!(tx_desc->wb.status & cpu_to_le32(IXGBE_TXD_STAT_DD)))

			break;
@@ -661,22 +659,18 @@ bool ixgbe_clean_xdp_tx_irq(struct ixgbe_q_vector *q_vector, 


		tx_bi++;

		tx_desc++;

		i++;

		if (unlikely(!i)) {

			i -= tx_ring->count;

		ntc++;

		if (unlikely(ntc == tx_ring->count)) {

			ntc = 0;

			tx_bi = tx_ring->tx_buffer_info;

			tx_desc = IXGBE_TX_DESC(tx_ring, 0);

		}



		/* issue prefetch for next Tx descriptor */

		prefetch(tx_desc);

	}



		/* update budget accounting */

		budget--;

	} while (likely(budget));



	i += tx_ring->count;

	tx_ring->next_to_clean = i;

	tx_ring->next_to_clean = ntc;



	u64_stats_update_begin(&tx_ring->syncp);

	tx_ring->stats.bytes += total_bytes;
@@ -688,8 +682,7 @@ bool ixgbe_clean_xdp_tx_irq(struct ixgbe_q_vector *q_vector, 
	if (xsk_frames)

		xsk_umem_complete_tx(umem, xsk_frames);



	xmit_done = ixgbe_xmit_zc(tx_ring, q_vector->tx.work_limit);

	return budget > 0 && xmit_done;

	return ixgbe_xmit_zc(tx_ring, q_vector->tx.work_limit);

}



int ixgbe_xsk_async_xmit(struct net_device *dev, u32 qid)

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