diff mbox series

[v3,net-next,7/7] ionic: Allow XDP program to be hot swapped

Message ID 20240906232623.39651-8-brett.creeley@amd.com (mailing list archive)
State Accepted
Commit 3c0bf13f5d5fcd6722e83a7203bf3dbb3ef73b6f
Delegated to: Netdev Maintainers
Headers show
Series ionic: convert Rx queue buffers to use page_pool | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 7 this patch: 7
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 5 maintainers not CCed: bpf@vger.kernel.org ast@kernel.org hawk@kernel.org daniel@iogearbox.net john.fastabend@gmail.com
netdev/build_clang success Errors and warnings before: 16 this patch: 16
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 16 this patch: 16
netdev/checkpatch warning WARNING: line length of 84 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-09-07--06-00 (tests: 722)

Commit Message

Brett Creeley Sept. 6, 2024, 11:26 p.m. UTC 
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@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.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 mbox series

Patch

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);