6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Shannon Nelson shannon.nelson@amd.com
[ Upstream commit 84b767f9e34fdb143c09e66a2a20722fc2921821 ]
If we're not in a NAPI softirq context, we need to be careful about how we call napi_consume_skb(), specifically we need to call it with budget==0 to signal to it that we're not in a safe context.
This was found while running some configuration stress testing of traffic and a change queue config loop running, and this curious note popped out:
[ 4371.402645] BUG: using smp_processor_id() in preemptible [00000000] code: ethtool/20545 [ 4371.402897] caller is napi_skb_cache_put+0x16/0x80 [ 4371.403120] CPU: 25 PID: 20545 Comm: ethtool Kdump: loaded Tainted: G OE 6.10.0-rc3-netnext+ #8 [ 4371.403302] Hardware name: HPE ProLiant DL360 Gen10/ProLiant DL360 Gen10, BIOS U32 01/23/2021 [ 4371.403460] Call Trace: [ 4371.403613] <TASK> [ 4371.403758] dump_stack_lvl+0x4f/0x70 [ 4371.403904] check_preemption_disabled+0xc1/0xe0 [ 4371.404051] napi_skb_cache_put+0x16/0x80 [ 4371.404199] ionic_tx_clean+0x18a/0x240 [ionic] [ 4371.404354] ionic_tx_cq_service+0xc4/0x200 [ionic] [ 4371.404505] ionic_tx_flush+0x15/0x70 [ionic] [ 4371.404653] ? ionic_lif_qcq_deinit.isra.23+0x5b/0x70 [ionic] [ 4371.404805] ionic_txrx_deinit+0x71/0x190 [ionic] [ 4371.404956] ionic_reconfigure_queues+0x5f5/0xff0 [ionic] [ 4371.405111] ionic_set_ringparam+0x2e8/0x3e0 [ionic] [ 4371.405265] ethnl_set_rings+0x1f1/0x300 [ 4371.405418] ethnl_default_set_doit+0xbb/0x160 [ 4371.405571] genl_family_rcv_msg_doit+0xff/0x130 [...]
I found that ionic_tx_clean() calls napi_consume_skb() which calls napi_skb_cache_put(), but before that last call is the note /* Zero budget indicate non-NAPI context called us, like netpoll */ and DEBUG_NET_WARN_ON_ONCE(!in_softirq());
Those are pretty big hints that we're doing it wrong. We can pass a context hint down through the calls to let ionic_tx_clean() know what we're doing so it can call napi_consume_skb() correctly.
Fixes: 386e69865311 ("ionic: Make use napi_consume_skb") Signed-off-by: Shannon Nelson shannon.nelson@amd.com Link: https://patch.msgid.link/20240624175015.4520-1-shannon.nelson@amd.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- .../net/ethernet/pensando/ionic/ionic_dev.h | 4 ++- .../net/ethernet/pensando/ionic/ionic_lif.c | 2 +- .../net/ethernet/pensando/ionic/ionic_txrx.c | 28 +++++++++++-------- 3 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_dev.h b/drivers/net/ethernet/pensando/ionic/ionic_dev.h index f30eee4a5a80e..b6c01a88098dc 100644 --- a/drivers/net/ethernet/pensando/ionic/ionic_dev.h +++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.h @@ -375,7 +375,9 @@ typedef void (*ionic_cq_done_cb)(void *done_arg); unsigned int ionic_cq_service(struct ionic_cq *cq, unsigned int work_to_do, ionic_cq_cb cb, ionic_cq_done_cb done_cb, void *done_arg); -unsigned int ionic_tx_cq_service(struct ionic_cq *cq, unsigned int work_to_do); +unsigned int ionic_tx_cq_service(struct ionic_cq *cq, + unsigned int work_to_do, + bool in_napi);
int ionic_q_init(struct ionic_lif *lif, struct ionic_dev *idev, struct ionic_queue *q, unsigned int index, const char *name, diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c index 0cd819bc4ae35..1dec4ebd708f2 100644 --- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c +++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c @@ -1189,7 +1189,7 @@ static int ionic_adminq_napi(struct napi_struct *napi, int budget) ionic_rx_service, NULL, NULL);
if (lif->hwstamp_txq) - tx_work = ionic_tx_cq_service(&lif->hwstamp_txq->cq, budget); + tx_work = ionic_tx_cq_service(&lif->hwstamp_txq->cq, budget, !!budget);
work_done = max(max(n_work, a_work), max(rx_work, tx_work)); if (work_done < budget && napi_complete_done(napi, work_done)) { diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c index aed7d9cbce038..9fdd7cd3ef19d 100644 --- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c +++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c @@ -23,7 +23,8 @@ static void ionic_tx_desc_unmap_bufs(struct ionic_queue *q,
static void ionic_tx_clean(struct ionic_queue *q, struct ionic_tx_desc_info *desc_info, - struct ionic_txq_comp *comp); + struct ionic_txq_comp *comp, + bool in_napi);
static inline void ionic_txq_post(struct ionic_queue *q, bool ring_dbell) { @@ -944,7 +945,7 @@ int ionic_tx_napi(struct napi_struct *napi, int budget) u32 work_done = 0; u32 flags = 0;
- work_done = ionic_tx_cq_service(cq, budget); + work_done = ionic_tx_cq_service(cq, budget, !!budget);
if (unlikely(!budget)) return budget; @@ -1028,7 +1029,7 @@ int ionic_txrx_napi(struct napi_struct *napi, int budget) txqcq = lif->txqcqs[qi]; txcq = &lif->txqcqs[qi]->cq;
- tx_work_done = ionic_tx_cq_service(txcq, IONIC_TX_BUDGET_DEFAULT); + tx_work_done = ionic_tx_cq_service(txcq, IONIC_TX_BUDGET_DEFAULT, !!budget);
if (unlikely(!budget)) return budget; @@ -1161,7 +1162,8 @@ static void ionic_tx_desc_unmap_bufs(struct ionic_queue *q,
static void ionic_tx_clean(struct ionic_queue *q, struct ionic_tx_desc_info *desc_info, - struct ionic_txq_comp *comp) + struct ionic_txq_comp *comp, + bool in_napi) { struct ionic_tx_stats *stats = q_to_tx_stats(q); struct ionic_qcq *qcq = q_to_qcq(q); @@ -1213,11 +1215,13 @@ static void ionic_tx_clean(struct ionic_queue *q, desc_info->bytes = skb->len; stats->clean++;
- napi_consume_skb(skb, 1); + napi_consume_skb(skb, likely(in_napi) ? 1 : 0); }
static bool ionic_tx_service(struct ionic_cq *cq, - unsigned int *total_pkts, unsigned int *total_bytes) + unsigned int *total_pkts, + unsigned int *total_bytes, + bool in_napi) { struct ionic_tx_desc_info *desc_info; struct ionic_queue *q = cq->bound_q; @@ -1239,7 +1243,7 @@ static bool ionic_tx_service(struct ionic_cq *cq, desc_info->bytes = 0; index = q->tail_idx; q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1); - ionic_tx_clean(q, desc_info, comp); + ionic_tx_clean(q, desc_info, comp, in_napi); if (desc_info->skb) { pkts++; bytes += desc_info->bytes; @@ -1253,7 +1257,9 @@ static bool ionic_tx_service(struct ionic_cq *cq, return true; }
-unsigned int ionic_tx_cq_service(struct ionic_cq *cq, unsigned int work_to_do) +unsigned int ionic_tx_cq_service(struct ionic_cq *cq, + unsigned int work_to_do, + bool in_napi) { unsigned int work_done = 0; unsigned int bytes = 0; @@ -1262,7 +1268,7 @@ unsigned int ionic_tx_cq_service(struct ionic_cq *cq, unsigned int work_to_do) if (work_to_do == 0) return 0;
- while (ionic_tx_service(cq, &pkts, &bytes)) { + while (ionic_tx_service(cq, &pkts, &bytes, in_napi)) { 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); @@ -1288,7 +1294,7 @@ void ionic_tx_flush(struct ionic_cq *cq) { u32 work_done;
- work_done = ionic_tx_cq_service(cq, cq->num_descs); + work_done = ionic_tx_cq_service(cq, cq->num_descs, false); if (work_done) ionic_intr_credits(cq->idev->intr_ctrl, cq->bound_intr->index, work_done, IONIC_INTR_CRED_RESET_COALESCE); @@ -1305,7 +1311,7 @@ void ionic_tx_empty(struct ionic_queue *q) desc_info = &q->tx_info[q->tail_idx]; desc_info->bytes = 0; q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1); - ionic_tx_clean(q, desc_info, NULL); + ionic_tx_clean(q, desc_info, NULL, false); if (desc_info->skb) { pkts++; bytes += desc_info->bytes;