[PATCH net v2 0/3] Add missing xdp_do_flush() invocations.

[PATCH net v2 0/3] Add missing xdp_do_flush() invocations.

[Sebastian Andrzej Siewior]

Hi,

I've been looking at the drivers/ XDP users and noticed that some
XDP_REDIRECT user don't invoke xdp_do_flush() at the end.

v1…v2: https://lore.kernel.org/all/20230908135748.794163-1-bigeasy@linutronix.de
  - Collected tags.
  - Dropped the #4 patch which was touching cpu_map_bpf_prog_run()
    because it is not needed.

Sebastian

[PATCH net v2 1/3] net: ena: Flush XDP packets on error.

[Sebastian Andrzej Siewior]

xdp_do_flush() should be invoked before leaving the NAPI poll function
after a XDP-redirect. This is not the case if the driver leaves via
the error path (after having a redirect in one of its previous
iterations).

Invoke xdp_do_flush() also in the error path.

Cc: Arthur Kiyanovski <akiyano@amazon.com>
Cc: David Arinzon <darinzon@amazon.com>
Cc: Noam Dagan <ndagan@amazon.com>
Cc: Saeed Bishara <saeedb@amazon.com>
Cc: Shay Agroskin <shayagr@amazon.com>
Fixes: a318c70ad152b ("net: ena: introduce XDP redirect implementation")
Acked-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index ad32ca81f7ef4..f955bde10cf90 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -1833,6 +1833,9 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
 	return work_done;
 
 error:
+	if (xdp_flags & ENA_XDP_REDIRECT)
+		xdp_do_flush();
+
 	adapter = netdev_priv(rx_ring->netdev);
 
 	if (rc == -ENOSPC) {
-- 
2.40.1

[PATCH net v2 2/3] bnxt_en: Flush XDP for bnxt_poll_nitroa0()'s NAPI

[Sebastian Andrzej Siewior]

bnxt_poll_nitroa0() invokes bnxt_rx_pkt() which can run a XDP program
which in turn can return XDP_REDIRECT. bnxt_rx_pkt() is also used by
__bnxt_poll_work() which flushes (xdp_do_flush()) the packets after each
round. bnxt_poll_nitroa0() lacks this feature.
xdp_do_flush() should be invoked before leaving the NAPI callback.

Invoke xdp_do_flush() after a redirect in bnxt_poll_nitroa0() NAPI.

Cc: Michael Chan <michael.chan@broadcom.com>
Fixes: f18c2b77b2e4e ("bnxt_en: optimized XDP_REDIRECT support")
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 5cc0dbe121327..7551aa8068f8f 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -2614,6 +2614,7 @@ static int bnxt_poll_nitroa0(struct napi_struct *napi, int budget)
 	struct rx_cmp_ext *rxcmp1;
 	u32 cp_cons, tmp_raw_cons;
 	u32 raw_cons = cpr->cp_raw_cons;
+	bool flush_xdp = false;
 	u32 rx_pkts = 0;
 	u8 event = 0;
 
@@ -2648,6 +2649,8 @@ static int bnxt_poll_nitroa0(struct napi_struct *napi, int budget)
 				rx_pkts++;
 			else if (rc == -EBUSY)	/* partial completion */
 				break;
+			if (event & BNXT_REDIRECT_EVENT)
+				flush_xdp = true;
 		} else if (unlikely(TX_CMP_TYPE(txcmp) ==
 				    CMPL_BASE_TYPE_HWRM_DONE)) {
 			bnxt_hwrm_handler(bp, txcmp);
@@ -2667,6 +2670,8 @@ static int bnxt_poll_nitroa0(struct napi_struct *napi, int budget)
 
 	if (event & BNXT_AGG_EVENT)
 		bnxt_db_write(bp, &rxr->rx_agg_db, rxr->rx_agg_prod);
+	if (flush_xdp)
+		xdp_do_flush();
 
 	if (!bnxt_has_work(bp, cpr) && rx_pkts < budget) {
 		napi_complete_done(napi, rx_pkts);
-- 
2.40.1

[PATCH net v2 3/3] octeontx2-pf: Do xdp_do_flush() after redirects.

[Sebastian Andrzej Siewior]

xdp_do_flush() should be invoked before leaving the NAPI poll function
if XDP-redirect has been performed.

Invoke xdp_do_flush() before leaving NAPI.

Cc: Geetha sowjanya <gakula@marvell.com>
Cc: Subbaraya Sundeep <sbhatta@marvell.com>
Cc: Sunil Goutham <sgoutham@marvell.com>
Cc: hariprasad <hkelam@marvell.com>
Fixes: 06059a1a9a4a5 ("octeontx2-pf: Add XDP support to netdev PF")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Geethasowjanya Akula <gakula@marvell.com>
---
 .../marvell/octeontx2/nic/otx2_txrx.c         | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
index e77d438489557..53b2a4ef52985 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
@@ -29,7 +29,8 @@
 static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
 				     struct bpf_prog *prog,
 				     struct nix_cqe_rx_s *cqe,
-				     struct otx2_cq_queue *cq);
+				     struct otx2_cq_queue *cq,
+				     bool *need_xdp_flush);
 
 static int otx2_nix_cq_op_status(struct otx2_nic *pfvf,
 				 struct otx2_cq_queue *cq)
@@ -337,7 +338,7 @@ static bool otx2_check_rcv_errors(struct otx2_nic *pfvf,
 static void otx2_rcv_pkt_handler(struct otx2_nic *pfvf,
 				 struct napi_struct *napi,
 				 struct otx2_cq_queue *cq,
-				 struct nix_cqe_rx_s *cqe)
+				 struct nix_cqe_rx_s *cqe, bool *need_xdp_flush)
 {
 	struct nix_rx_parse_s *parse = &cqe->parse;
 	struct nix_rx_sg_s *sg = &cqe->sg;
@@ -353,7 +354,7 @@ static void otx2_rcv_pkt_handler(struct otx2_nic *pfvf,
 	}
 
 	if (pfvf->xdp_prog)
-		if (otx2_xdp_rcv_pkt_handler(pfvf, pfvf->xdp_prog, cqe, cq))
+		if (otx2_xdp_rcv_pkt_handler(pfvf, pfvf->xdp_prog, cqe, cq, need_xdp_flush))
 			return;
 
 	skb = napi_get_frags(napi);
@@ -388,6 +389,7 @@ static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
 				struct napi_struct *napi,
 				struct otx2_cq_queue *cq, int budget)
 {
+	bool need_xdp_flush = false;
 	struct nix_cqe_rx_s *cqe;
 	int processed_cqe = 0;
 
@@ -409,13 +411,15 @@ static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
 		cq->cq_head++;
 		cq->cq_head &= (cq->cqe_cnt - 1);
 
-		otx2_rcv_pkt_handler(pfvf, napi, cq, cqe);
+		otx2_rcv_pkt_handler(pfvf, napi, cq, cqe, &need_xdp_flush);
 
 		cqe->hdr.cqe_type = NIX_XQE_TYPE_INVALID;
 		cqe->sg.seg_addr = 0x00;
 		processed_cqe++;
 		cq->pend_cqe--;
 	}
+	if (need_xdp_flush)
+		xdp_do_flush();
 
 	/* Free CQEs to HW */
 	otx2_write64(pfvf, NIX_LF_CQ_OP_DOOR,
@@ -1354,7 +1358,8 @@ bool otx2_xdp_sq_append_pkt(struct otx2_nic *pfvf, u64 iova, int len, u16 qidx)
 static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
 				     struct bpf_prog *prog,
 				     struct nix_cqe_rx_s *cqe,
-				     struct otx2_cq_queue *cq)
+				     struct otx2_cq_queue *cq,
+				     bool *need_xdp_flush)
 {
 	unsigned char *hard_start, *data;
 	int qidx = cq->cq_idx;
@@ -1391,8 +1396,10 @@ static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
 
 		otx2_dma_unmap_page(pfvf, iova, pfvf->rbsize,
 				    DMA_FROM_DEVICE);
-		if (!err)
+		if (!err) {
+			*need_xdp_flush = true;
 			return true;
+		}
 		put_page(page);
 		break;
 	default:
-- 
2.40.1

Re: [PATCH net v2 2/3] bnxt_en: Flush XDP for bnxt_poll_nitroa0()'s NAPI

[Michael Chan]

On Mon, Sep 18, 2023 at 8:36 AM Sebastian Andrzej Siewior
<bigeasy@linutronix.de> wrote:
>
> bnxt_poll_nitroa0() invokes bnxt_rx_pkt() which can run a XDP program
> which in turn can return XDP_REDIRECT. bnxt_rx_pkt() is also used by
> __bnxt_poll_work() which flushes (xdp_do_flush()) the packets after each
> round. bnxt_poll_nitroa0() lacks this feature.
> xdp_do_flush() should be invoked before leaving the NAPI callback.
>
> Invoke xdp_do_flush() after a redirect in bnxt_poll_nitroa0() NAPI.
>
> Cc: Michael Chan <michael.chan@broadcom.com>
> Fixes: f18c2b77b2e4e ("bnxt_en: optimized XDP_REDIRECT support")
> Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Reviewed-by: Michael Chan <michael.chan@broadcom.com>

Thanks.

Re: [PATCH net v2 3/3] octeontx2-pf: Do xdp_do_flush() after redirects.

[Kui-Feng Lee]

On 9/18/23 08:36, Sebastian Andrzej Siewior wrote:
> xdp_do_flush() should be invoked before leaving the NAPI poll function
> if XDP-redirect has been performed.
> 
> Invoke xdp_do_flush() before leaving NAPI.
> 
> Cc: Geetha sowjanya <gakula@marvell.com>
> Cc: Subbaraya Sundeep <sbhatta@marvell.com>
> Cc: Sunil Goutham <sgoutham@marvell.com>
> Cc: hariprasad <hkelam@marvell.com>
> Fixes: 06059a1a9a4a5 ("octeontx2-pf: Add XDP support to netdev PF")
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Acked-by: Geethasowjanya Akula <gakula@marvell.com>
> ---
>   .../marvell/octeontx2/nic/otx2_txrx.c         | 19 +++++++++++++------
>   1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> index e77d438489557..53b2a4ef52985 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> @@ -29,7 +29,8 @@
>   static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
>   				     struct bpf_prog *prog,
>   				     struct nix_cqe_rx_s *cqe,
> -				     struct otx2_cq_queue *cq);
> +				     struct otx2_cq_queue *cq,
> +				     bool *need_xdp_flush);
>   
>   static int otx2_nix_cq_op_status(struct otx2_nic *pfvf,
>   				 struct otx2_cq_queue *cq)
> @@ -337,7 +338,7 @@ static bool otx2_check_rcv_errors(struct otx2_nic *pfvf,
>   static void otx2_rcv_pkt_handler(struct otx2_nic *pfvf,
>   				 struct napi_struct *napi,
>   				 struct otx2_cq_queue *cq,
> -				 struct nix_cqe_rx_s *cqe)
> +				 struct nix_cqe_rx_s *cqe, bool *need_xdp_flush)
>   {
>   	struct nix_rx_parse_s *parse = &cqe->parse;
>   	struct nix_rx_sg_s *sg = &cqe->sg;
> @@ -353,7 +354,7 @@ static void otx2_rcv_pkt_handler(struct otx2_nic *pfvf,
>   	}
>   
>   	if (pfvf->xdp_prog)
> -		if (otx2_xdp_rcv_pkt_handler(pfvf, pfvf->xdp_prog, cqe, cq))
> +		if (otx2_xdp_rcv_pkt_handler(pfvf, pfvf->xdp_prog, cqe, cq, need_xdp_flush))
>   			return;
>   
>   	skb = napi_get_frags(napi);
> @@ -388,6 +389,7 @@ static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
>   				struct napi_struct *napi,
>   				struct otx2_cq_queue *cq, int budget)
>   {
> +	bool need_xdp_flush = false;
>   	struct nix_cqe_rx_s *cqe;
>   	int processed_cqe = 0;
>   
> @@ -409,13 +411,15 @@ static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
>   		cq->cq_head++;
>   		cq->cq_head &= (cq->cqe_cnt - 1);
>   
> -		otx2_rcv_pkt_handler(pfvf, napi, cq, cqe);
> +		otx2_rcv_pkt_handler(pfvf, napi, cq, cqe, &need_xdp_flush);
>   
>   		cqe->hdr.cqe_type = NIX_XQE_TYPE_INVALID;
>   		cqe->sg.seg_addr = 0x00;
>   		processed_cqe++;
>   		cq->pend_cqe--;
>   	}
> +	if (need_xdp_flush)
> +		xdp_do_flush();
>   
>   	/* Free CQEs to HW */
>   	otx2_write64(pfvf, NIX_LF_CQ_OP_DOOR,
> @@ -1354,7 +1358,8 @@ bool otx2_xdp_sq_append_pkt(struct otx2_nic *pfvf, u64 iova, int len, u16 qidx)
>   static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
>   				     struct bpf_prog *prog,
>   				     struct nix_cqe_rx_s *cqe,
> -				     struct otx2_cq_queue *cq)
> +				     struct otx2_cq_queue *cq,
> +				     bool *need_xdp_flush)
>   {
>   	unsigned char *hard_start, *data;
>   	int qidx = cq->cq_idx;
> @@ -1391,8 +1396,10 @@ static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
>   
>   		otx2_dma_unmap_page(pfvf, iova, pfvf->rbsize,
>   				    DMA_FROM_DEVICE);
> -		if (!err)
> +		if (!err) {
> +			*need_xdp_flush = true;

Is it possible to call xdp_do_flush() at the first place (here)?

>   			return true;
> +		}
>   		put_page(page);
>   		break;
>   	default:

Re: [PATCH net v2 3/3] octeontx2-pf: Do xdp_do_flush() after redirects.

[Sebastian Andrzej Siewior]

On 2023-09-18 10:58:39 [-0700], Kui-Feng Lee wrote:
> > diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> > index e77d438489557..53b2a4ef52985 100644
> > --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> > +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> > @@ -1391,8 +1396,10 @@ static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
> >   		otx2_dma_unmap_page(pfvf, iova, pfvf->rbsize,
> >   				    DMA_FROM_DEVICE);
> > -		if (!err)
> > +		if (!err) {
> > +			*need_xdp_flush = true;
> 
> Is it possible to call xdp_do_flush() at the first place (here)?

It shouldn't be wrong. All drivers, except for cpsw, invoke
xdp_do_flush() after completing their NAPI loop and then flushing all
possible packets at once.

> >   			return true;
> > +		}
> >   		put_page(page);
> >   		break;
> >   	default:

Sebastian

Re: [PATCH net v2 0/3] Add missing xdp_do_flush() invocations.

[Jesper Dangaard Brouer]

Hi Sebastian,


On 18/09/2023 17.36, Sebastian Andrzej Siewior wrote:
> Hi,
> 
> I've been looking at the drivers/ XDP users and noticed that some
> XDP_REDIRECT user don't invoke xdp_do_flush() at the end.

I'm wondering if we could detect (and WARN) in the net core e.g.
net_rx_action() that a driver is missing a flush?

The idea could be to check the per CPU (struct) bpf_redirect_info.
Or check (per CPU) dev_flush_list.

If some is worried about performance implications, then we can hide this
under CONFIG_DEBUG_NET.

> v1…v2: https://lore.kernel.org/all/20230908135748.794163-1-bigeasy@linutronix.de
>    - Collected tags.
>    - Dropped the #4 patch which was touching cpu_map_bpf_prog_run()
>      because it is not needed.
> 

For the fixes in this set:

Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>

Thanks for fixing these! - at it can lead to strange to debug cases.
--Jesper

Re: [PATCH net v2 0/3] Add missing xdp_do_flush() invocations.

[Sebastian Andrzej Siewior]

On 2023-09-20 09:04:27 [+0200], Jesper Dangaard Brouer wrote:
> Hi Sebastian,

Hi Jesper,

> On 18/09/2023 17.36, Sebastian Andrzej Siewior wrote:
> > Hi,
> > 
> > I've been looking at the drivers/ XDP users and noticed that some
> > XDP_REDIRECT user don't invoke xdp_do_flush() at the end.
> 
> I'm wondering if we could detect (and WARN) in the net core e.g.
> net_rx_action() that a driver is missing a flush?
> 
> The idea could be to check the per CPU (struct) bpf_redirect_info.
> Or check (per CPU) dev_flush_list.
> 
> If some is worried about performance implications, then we can hide this
> under CONFIG_DEBUG_NET.

I had a WARN_ON in mind since the list has to be empty after the
completion of a NAPI callback. Now that you are bringing it up let me
actually do something…

> --Jesper

Sebastian

Re: [PATCH net v2 3/3] octeontx2-pf: Do xdp_do_flush() after redirects.

[Paolo Abeni]

On Mon, 2023-09-18 at 10:58 -0700, Kui-Feng Lee wrote:
> 
> On 9/18/23 08:36, Sebastian Andrzej Siewior wrote:
> > xdp_do_flush() should be invoked before leaving the NAPI poll function
> > if XDP-redirect has been performed.
> > 
> > Invoke xdp_do_flush() before leaving NAPI.
> > 
> > Cc: Geetha sowjanya <gakula@marvell.com>
> > Cc: Subbaraya Sundeep <sbhatta@marvell.com>
> > Cc: Sunil Goutham <sgoutham@marvell.com>
> > Cc: hariprasad <hkelam@marvell.com>
> > Fixes: 06059a1a9a4a5 ("octeontx2-pf: Add XDP support to netdev PF")
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> > Acked-by: Geethasowjanya Akula <gakula@marvell.com>
> > ---
> >   .../marvell/octeontx2/nic/otx2_txrx.c         | 19 +++++++++++++------
> >   1 file changed, 13 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> > index e77d438489557..53b2a4ef52985 100644
> > --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> > +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
> > @@ -29,7 +29,8 @@
> >   static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
> >   				     struct bpf_prog *prog,
> >   				     struct nix_cqe_rx_s *cqe,
> > -				     struct otx2_cq_queue *cq);
> > +				     struct otx2_cq_queue *cq,
> > +				     bool *need_xdp_flush);
> >   
> >   static int otx2_nix_cq_op_status(struct otx2_nic *pfvf,
> >   				 struct otx2_cq_queue *cq)
> > @@ -337,7 +338,7 @@ static bool otx2_check_rcv_errors(struct otx2_nic *pfvf,
> >   static void otx2_rcv_pkt_handler(struct otx2_nic *pfvf,
> >   				 struct napi_struct *napi,
> >   				 struct otx2_cq_queue *cq,
> > -				 struct nix_cqe_rx_s *cqe)
> > +				 struct nix_cqe_rx_s *cqe, bool *need_xdp_flush)
> >   {
> >   	struct nix_rx_parse_s *parse = &cqe->parse;
> >   	struct nix_rx_sg_s *sg = &cqe->sg;
> > @@ -353,7 +354,7 @@ static void otx2_rcv_pkt_handler(struct otx2_nic *pfvf,
> >   	}
> >   
> >   	if (pfvf->xdp_prog)
> > -		if (otx2_xdp_rcv_pkt_handler(pfvf, pfvf->xdp_prog, cqe, cq))
> > +		if (otx2_xdp_rcv_pkt_handler(pfvf, pfvf->xdp_prog, cqe, cq, need_xdp_flush))
> >   			return;
> >   
> >   	skb = napi_get_frags(napi);
> > @@ -388,6 +389,7 @@ static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
> >   				struct napi_struct *napi,
> >   				struct otx2_cq_queue *cq, int budget)
> >   {
> > +	bool need_xdp_flush = false;
> >   	struct nix_cqe_rx_s *cqe;
> >   	int processed_cqe = 0;
> >   
> > @@ -409,13 +411,15 @@ static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
> >   		cq->cq_head++;
> >   		cq->cq_head &= (cq->cqe_cnt - 1);
> >   
> > -		otx2_rcv_pkt_handler(pfvf, napi, cq, cqe);
> > +		otx2_rcv_pkt_handler(pfvf, napi, cq, cqe, &need_xdp_flush);
> >   
> >   		cqe->hdr.cqe_type = NIX_XQE_TYPE_INVALID;
> >   		cqe->sg.seg_addr = 0x00;
> >   		processed_cqe++;
> >   		cq->pend_cqe--;
> >   	}
> > +	if (need_xdp_flush)
> > +		xdp_do_flush();
> >   
> >   	/* Free CQEs to HW */
> >   	otx2_write64(pfvf, NIX_LF_CQ_OP_DOOR,
> > @@ -1354,7 +1358,8 @@ bool otx2_xdp_sq_append_pkt(struct otx2_nic *pfvf, u64 iova, int len, u16 qidx)
> >   static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
> >   				     struct bpf_prog *prog,
> >   				     struct nix_cqe_rx_s *cqe,
> > -				     struct otx2_cq_queue *cq)
> > +				     struct otx2_cq_queue *cq,
> > +				     bool *need_xdp_flush)
> >   {
> >   	unsigned char *hard_start, *data;
> >   	int qidx = cq->cq_idx;
> > @@ -1391,8 +1396,10 @@ static bool otx2_xdp_rcv_pkt_handler(struct otx2_nic *pfvf,
> >   
> >   		otx2_dma_unmap_page(pfvf, iova, pfvf->rbsize,
> >   				    DMA_FROM_DEVICE);
> > -		if (!err)
> > +		if (!err) {
> > +			*need_xdp_flush = true;
> 
> Is it possible to call xdp_do_flush() at the first place (here)?

AFAICT that would kill much/all of the performance benefits of bulk
redirect.

I think the proposed solution is a better one.

Cheers,

Paolo

Re: [PATCH net v2 0/3] Add missing xdp_do_flush() invocations.

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Mon, 18 Sep 2023 17:36:08 +0200 you wrote:
> Hi,
> 
> I've been looking at the drivers/ XDP users and noticed that some
> XDP_REDIRECT user don't invoke xdp_do_flush() at the end.
> 
> v1…v2: https://lore.kernel.org/all/20230908135748.794163-1-bigeasy@linutronix.de
>   - Collected tags.
>   - Dropped the #4 patch which was touching cpu_map_bpf_prog_run()
>     because it is not needed.
> 
> [...]

Here is the summary with links:
  - [net,v2,1/3] net: ena: Flush XDP packets on error.
    https://git.kernel.org/netdev/net/c/6f411fb5ca94
  - [net,v2,2/3] bnxt_en: Flush XDP for bnxt_poll_nitroa0()'s NAPI
    https://git.kernel.org/netdev/net/c/edc0140cc3b7
  - [net,v2,3/3] octeontx2-pf: Do xdp_do_flush() after redirects.
    https://git.kernel.org/netdev/net/c/70b2b6892645

You are awesome, thank you!
-- 
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