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Message-ID: <20240906232623.39651-8-brett.creeley@amd.com>
Date: Fri, 6 Sep 2024 16:26:23 -0700
From: Brett Creeley <brett.creeley@....com>
To: <netdev@...r.kernel.org>, <davem@...emloft.net>, <kuba@...nel.org>,
<edumazet@...gle.com>, <pabeni@...hat.com>
CC: <shannon.nelson@....com>, <brett.creeley@....com>
Subject: [PATCH v3 net-next 7/7] ionic: Allow XDP program to be hot swapped
Using examples of other driver(s), add the ability to hot-swap an XDP
program without having to reconfigure the queues. To prevent the
q->xdp_prog to be read/written more than once use READ_ONCE() and
WRITE_ONCE() on the q->xdp_prog.
The q->xdp_prog was being checked in multiple different for loops in the
hot path. The change to allow xdp_prog hot swapping created the
possibility for many READ_ONCE(q->xdp_prog) calls during a single napi
callback. Refactor the Rx napi handling to allow a previous
READ_ONCE(q->xdp_prog) (or NULL for hwstamp_rxq) to be passed into the
relevant functions.
Also, move other Rx related hotpath handling into the newly created
ionic_rx_cq_service() function to reduce the scope of the xdp_prog
local variable and put all Rx handling in one function similar to Tx.
Signed-off-by: Brett Creeley <brett.creeley@....com>
Signed-off-by: Shannon Nelson <shannon.nelson@....com>
---
.../net/ethernet/pensando/ionic/ionic_lif.c | 12 ++--
.../net/ethernet/pensando/ionic/ionic_txrx.c | 58 +++++++++++++------
.../net/ethernet/pensando/ionic/ionic_txrx.h | 4 +-
3 files changed, 52 insertions(+), 22 deletions(-)
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
index 59d3eea2c0bc..a3965532464f 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
@@ -1074,7 +1074,7 @@ int ionic_lif_create_hwstamp_rxq(struct ionic_lif *lif)
goto err_qcq_init;
if (test_bit(IONIC_LIF_F_UP, lif->state)) {
- ionic_rx_fill(&rxq->q);
+ ionic_rx_fill(&rxq->q, NULL);
err = ionic_qcq_enable(rxq);
if (err)
goto err_qcq_enable;
@@ -2190,7 +2190,8 @@ static int ionic_txrx_enable(struct ionic_lif *lif)
goto err_out;
}
- ionic_rx_fill(&lif->rxqcqs[i]->q);
+ ionic_rx_fill(&lif->rxqcqs[i]->q,
+ READ_ONCE(lif->rxqcqs[i]->q.xdp_prog));
err = ionic_qcq_enable(lif->rxqcqs[i]);
if (err)
goto err_out;
@@ -2203,7 +2204,7 @@ static int ionic_txrx_enable(struct ionic_lif *lif)
}
if (lif->hwstamp_rxq) {
- ionic_rx_fill(&lif->hwstamp_rxq->q);
+ ionic_rx_fill(&lif->hwstamp_rxq->q, NULL);
err = ionic_qcq_enable(lif->hwstamp_rxq);
if (err)
goto err_out_hwstamp_rx;
@@ -2746,7 +2747,7 @@ static void ionic_xdp_rxqs_prog_update(struct ionic_lif *lif)
for (i = 0; i < lif->ionic->nrxqs_per_lif && lif->rxqcqs[i]; i++) {
struct ionic_queue *q = &lif->rxqcqs[i]->q;
- q->xdp_prog = xdp_prog;
+ WRITE_ONCE(q->xdp_prog, xdp_prog);
}
}
@@ -2777,6 +2778,9 @@ static int ionic_xdp_config(struct net_device *netdev, struct netdev_bpf *bpf)
if (!netif_running(netdev)) {
old_prog = xchg(&lif->xdp_prog, bpf->prog);
+ } else if (lif->xdp_prog && bpf->prog) {
+ old_prog = xchg(&lif->xdp_prog, bpf->prog);
+ ionic_xdp_rxqs_prog_update(lif);
} else {
struct ionic_queue_params qparams;
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 35e3751dd5a7..0eeda7e502db 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -602,7 +602,8 @@ static bool ionic_run_xdp(struct ionic_rx_stats *stats,
static void ionic_rx_clean(struct ionic_queue *q,
struct ionic_rx_desc_info *desc_info,
- struct ionic_rxq_comp *comp)
+ struct ionic_rxq_comp *comp,
+ struct bpf_prog *xdp_prog)
{
struct net_device *netdev = q->lif->netdev;
struct ionic_qcq *qcq = q_to_qcq(q);
@@ -631,8 +632,8 @@ static void ionic_rx_clean(struct ionic_queue *q,
stats->pkts++;
stats->bytes += len;
- if (q->xdp_prog) {
- if (ionic_run_xdp(stats, netdev, q->xdp_prog, q, desc_info->bufs, len))
+ if (xdp_prog) {
+ if (ionic_run_xdp(stats, netdev, xdp_prog, q, desc_info->bufs, len))
return;
synced = true;
headroom = XDP_PACKET_HEADROOM;
@@ -718,7 +719,7 @@ static void ionic_rx_clean(struct ionic_queue *q,
napi_gro_frags(&qcq->napi);
}
-bool ionic_rx_service(struct ionic_cq *cq)
+static bool __ionic_rx_service(struct ionic_cq *cq, struct bpf_prog *xdp_prog)
{
struct ionic_rx_desc_info *desc_info;
struct ionic_queue *q = cq->bound_q;
@@ -740,11 +741,16 @@ bool ionic_rx_service(struct ionic_cq *cq)
q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
/* clean the related q entry, only one per qc completion */
- ionic_rx_clean(q, desc_info, comp);
+ ionic_rx_clean(q, desc_info, comp, xdp_prog);
return true;
}
+bool ionic_rx_service(struct ionic_cq *cq)
+{
+ return __ionic_rx_service(cq, NULL);
+}
+
static inline void ionic_write_cmb_desc(struct ionic_queue *q,
void *desc)
{
@@ -755,7 +761,7 @@ static inline void ionic_write_cmb_desc(struct ionic_queue *q,
memcpy_toio(&q->cmb_txq[q->head_idx], desc, sizeof(q->cmb_txq[0]));
}
-void ionic_rx_fill(struct ionic_queue *q)
+void ionic_rx_fill(struct ionic_queue *q, struct bpf_prog *xdp_prog)
{
struct net_device *netdev = q->lif->netdev;
struct ionic_rx_desc_info *desc_info;
@@ -783,7 +789,7 @@ void ionic_rx_fill(struct ionic_queue *q)
len = netdev->mtu + VLAN_ETH_HLEN;
- if (q->xdp_prog) {
+ if (xdp_prog) {
/* Always alloc the full size buffer, but only need
* the actual frag_len in the descriptor
* XDP uses space in the first buffer, so account for
@@ -964,6 +970,32 @@ static void ionic_xdp_do_flush(struct ionic_cq *cq)
}
}
+static unsigned int ionic_rx_cq_service(struct ionic_cq *cq,
+ unsigned int work_to_do)
+{
+ struct ionic_queue *q = cq->bound_q;
+ unsigned int work_done = 0;
+ struct bpf_prog *xdp_prog;
+
+ if (work_to_do == 0)
+ return 0;
+
+ xdp_prog = READ_ONCE(q->xdp_prog);
+ while (__ionic_rx_service(cq, xdp_prog)) {
+ if (cq->tail_idx == cq->num_descs - 1)
+ cq->done_color = !cq->done_color;
+
+ cq->tail_idx = (cq->tail_idx + 1) & (cq->num_descs - 1);
+
+ if (++work_done >= work_to_do)
+ break;
+ }
+ ionic_rx_fill(q, xdp_prog);
+ ionic_xdp_do_flush(cq);
+
+ return work_done;
+}
+
int ionic_rx_napi(struct napi_struct *napi, int budget)
{
struct ionic_qcq *qcq = napi_to_qcq(napi);
@@ -974,12 +1006,8 @@ int ionic_rx_napi(struct napi_struct *napi, int budget)
if (unlikely(!budget))
return budget;
- work_done = ionic_cq_service(cq, budget,
- ionic_rx_service, NULL, NULL);
+ work_done = ionic_rx_cq_service(cq, budget);
- ionic_rx_fill(cq->bound_q);
-
- ionic_xdp_do_flush(cq);
if (work_done < budget && napi_complete_done(napi, work_done)) {
ionic_dim_update(qcq, IONIC_LIF_F_RX_DIM_INTR);
flags |= IONIC_INTR_CRED_UNMASK;
@@ -1020,12 +1048,8 @@ int ionic_txrx_napi(struct napi_struct *napi, int budget)
if (unlikely(!budget))
return budget;
- rx_work_done = ionic_cq_service(rxcq, budget,
- ionic_rx_service, NULL, NULL);
-
- ionic_rx_fill(rxcq->bound_q);
+ rx_work_done = ionic_rx_cq_service(rxcq, budget);
- ionic_xdp_do_flush(rxcq);
if (rx_work_done < budget && napi_complete_done(napi, rx_work_done)) {
ionic_dim_update(rxqcq, 0);
flags |= IONIC_INTR_CRED_UNMASK;
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.h b/drivers/net/ethernet/pensando/ionic/ionic_txrx.h
index 9e73e324e7a1..b2b9a2dc9eb8 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.h
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.h
@@ -4,9 +4,11 @@
#ifndef _IONIC_TXRX_H_
#define _IONIC_TXRX_H_
+struct bpf_prog;
+
void ionic_tx_flush(struct ionic_cq *cq);
-void ionic_rx_fill(struct ionic_queue *q);
+void ionic_rx_fill(struct ionic_queue *q, struct bpf_prog *xdp_prog);
void ionic_rx_empty(struct ionic_queue *q);
void ionic_tx_empty(struct ionic_queue *q);
int ionic_rx_napi(struct napi_struct *napi, int budget);
--
2.17.1
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