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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Subject: [PATCH net v1 2/2] octeon_ep_vf: avoid compiler and IQ/OQ reordering Date: Fri, 19 Dec 2025 07:29:53 +0000 Message-ID: <20251219072955.3048238-3-vimleshk@marvell.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251219072955.3048238-1-vimleshk@marvell.com> References: <20251219072955.3048238-1-vimleshk@marvell.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMjE5MDA2MSBTYWx0ZWRfX8y10MFmUOnho O8gTiTYNhRtiRytqv9WwwICVQ2OJW582hmxRlIkH1AQj4KBpQxyeZjfgQ2oeiTVN1B2bIh/iGRQ BuXGVFochZGjjbvy6ysZ6auJrsR216xqUbOQzhpyMqix7xNI0GqXgGJqyvrEBWhktgPMOFd7b7z OeLrVmc+qe2QlaHJvCYPM3Oa5JEZNAF7d0+mSXbEIcabJqWAgjl8aEAU43ne+lB47dJN06Qhnto OUYMXJXhJF09EZO4YlFOoDVCg9+JSeR1z0Asb8a+WlCWM6xo+8791O/jrKROtF4w05N3LuG53na w58O1GNOyrRbUlz1GsKno2olGdb3vIGUbSqZBcdLwMGbYXSOZKcntwQbjOVMcNd9EupETJDwQaL 3HHeM2vgp8uTyackybuAZ+Xnvb7+fHBsap89ctTjUnW3Tu5qf0VutNa6ybUA3Z3kruelc5HowIn LQCwDpAXRpVVIVhzXEg== X-Proofpoint-ORIG-GUID: mVZOWPAPicIC8o4JTR3iQrVtmfBDFl86 X-Authority-Analysis: v=2.4 cv=T4uBjvKQ c=1 sm=1 tr=0 ts=6944fefe cx=c_pps a=gIfcoYsirJbf48DBMSPrZA==:117 a=gIfcoYsirJbf48DBMSPrZA==:17 a=wP3pNCr1ah4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=M5GUcnROAAAA:8 a=zFyd0VMmUU5vBRt5t4UA:9 a=OBjm3rFKGHvpk9ecZwUJ:22 X-Proofpoint-GUID: mVZOWPAPicIC8o4JTR3iQrVtmfBDFl86 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-12-19_02,2025-12-17_02,2025-10-01_01 Content-Type: text/plain; charset="utf-8" Utilize READ_ONCE and WRITE_ONCE APIs for IO queue Tx/Rx variable access to prevent compiler optimization and reordering. Additionally, ensure IO queue OUT/IN_CNT registers are flushed by performing a read-back after writing. Relocate IQ/OQ IN/OUT_CNTS updates to occur before NAPI completion, and replace napi_complete with napi_complete_done. Fixes: 1cd3b407977c3 ("octeon_ep_vf: add Tx/Rx processing and interrupt sup= port") Signed-off-by: Sathesh Edara Signed-off-by: Shinas Rasheed Signed-off-by: Vimlesh Kumar --- .../marvell/octeon_ep_vf/octep_vf_main.c | 38 ++++++++++++++----- .../marvell/octeon_ep_vf/octep_vf_rx.c | 28 ++++++++++---- 2 files changed, 48 insertions(+), 18 deletions(-) diff --git a/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_main.c b/dr= ivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_main.c index 420c3f4cf741..27a5fc38bccb 100644 --- a/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_main.c +++ b/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_main.c @@ -286,28 +286,45 @@ static void octep_vf_clean_irqs(struct octep_vf_devic= e *oct) } =20 /** - * octep_vf_enable_ioq_irq() - Enable MSI-x interrupt of a Tx/Rx queue. + * octep_vf_update_pkt() - Update IQ/OQ IN/OUT_CNT registers. * * @iq: Octeon Tx queue data structure. * @oq: Octeon Rx queue data structure. */ -static void octep_vf_enable_ioq_irq(struct octep_vf_iq *iq, struct octep_v= f_oq *oq) + +static void octep_vf_update_pkt(struct octep_vf_iq *iq, struct octep_vf_oq= *oq) { - u32 pkts_pend =3D oq->pkts_pending; + u32 pkts_pend =3D READ_ONCE(oq->pkts_pending); + u32 last_pkt_count =3D READ_ONCE(oq->last_pkt_count); + u32 pkts_processed =3D READ_ONCE(iq->pkts_processed); + u32 pkt_in_done =3D READ_ONCE(iq->pkt_in_done); =20 netdev_dbg(iq->netdev, "enabling intr for Q-%u\n", iq->q_no); - if (iq->pkts_processed) { - writel(iq->pkts_processed, iq->inst_cnt_reg); - iq->pkt_in_done -=3D iq->pkts_processed; - iq->pkts_processed =3D 0; + if (pkts_processed) { + writel(pkts_processed, iq->inst_cnt_reg); + readl(iq->inst_cnt_reg); + WRITE_ONCE(iq->pkt_in_done, (pkt_in_done - pkts_processed)); + WRITE_ONCE(iq->pkts_processed, 0); } - if (oq->last_pkt_count - pkts_pend) { - writel(oq->last_pkt_count - pkts_pend, oq->pkts_sent_reg); - oq->last_pkt_count =3D pkts_pend; + if (last_pkt_count - pkts_pend) { + writel(last_pkt_count - pkts_pend, oq->pkts_sent_reg); + readl(oq->pkts_sent_reg); + WRITE_ONCE(oq->last_pkt_count, pkts_pend); } =20 /* Flush the previous wrties before writing to RESEND bit */ smp_wmb(); +} + +/** + * octep_vf_enable_ioq_irq() - Enable MSI-x interrupt of a Tx/Rx queue. + * + * @iq: Octeon Tx queue data structure. + * @oq: Octeon Rx queue data structure. + */ +static void octep_vf_enable_ioq_irq(struct octep_vf_iq *iq, + struct octep_vf_oq *oq) +{ writeq(1UL << OCTEP_VF_OQ_INTR_RESEND_BIT, oq->pkts_sent_reg); writeq(1UL << OCTEP_VF_IQ_INTR_RESEND_BIT, iq->inst_cnt_reg); } @@ -333,6 +350,7 @@ static int octep_vf_napi_poll(struct napi_struct *napi,= int budget) if (tx_pending || rx_done >=3D budget) return budget; =20 + octep_vf_update_pkt(ioq_vector->iq, ioq_vector->oq); if (likely(napi_complete_done(napi, rx_done))) octep_vf_enable_ioq_irq(ioq_vector->iq, ioq_vector->oq); =20 diff --git a/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_rx.c b/driv= ers/net/ethernet/marvell/octeon_ep_vf/octep_vf_rx.c index d70c8be3cfc4..31380962c212 100644 --- a/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_rx.c +++ b/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_rx.c @@ -319,9 +319,16 @@ static int octep_vf_oq_check_hw_for_pkts(struct octep_= vf_device *oct, struct octep_vf_oq *oq) { u32 pkt_count, new_pkts; + u32 last_pkt_count, pkts_pending; =20 pkt_count =3D readl(oq->pkts_sent_reg); - new_pkts =3D pkt_count - oq->last_pkt_count; + last_pkt_count =3D READ_ONCE(oq->last_pkt_count); + new_pkts =3D pkt_count - last_pkt_count; + + if (pkt_count < last_pkt_count) { + dev_err(oq->dev, "OQ-%u pkt_count(%u) < oq->last_pkt_count(%u)\n", + oq->q_no, pkt_count, last_pkt_count); + } =20 /* Clear the hardware packets counter register if the rx queue is * being processed continuously with-in a single interrupt and @@ -333,8 +340,9 @@ static int octep_vf_oq_check_hw_for_pkts(struct octep_v= f_device *oct, pkt_count =3D readl(oq->pkts_sent_reg); new_pkts +=3D pkt_count; } - oq->last_pkt_count =3D pkt_count; - oq->pkts_pending +=3D new_pkts; + WRITE_ONCE(oq->last_pkt_count, pkt_count); + pkts_pending =3D READ_ONCE(oq->pkts_pending); + WRITE_ONCE(oq->pkts_pending, (pkts_pending + new_pkts)); return new_pkts; } =20 @@ -363,7 +371,7 @@ static int __octep_vf_oq_process_rx(struct octep_vf_dev= ice *oct, struct sk_buff *skb; u32 read_idx; =20 - read_idx =3D oq->host_read_idx; + read_idx =3D READ_ONCE(oq->host_read_idx); rx_bytes =3D 0; desc_used =3D 0; for (pkt =3D 0; pkt < pkts_to_process; pkt++) { @@ -457,7 +465,7 @@ static int __octep_vf_oq_process_rx(struct octep_vf_dev= ice *oct, napi_gro_receive(oq->napi, skb); } =20 - oq->host_read_idx =3D read_idx; + WRITE_ONCE(oq->host_read_idx, read_idx); oq->refill_count +=3D desc_used; oq->stats->packets +=3D pkt; oq->stats->bytes +=3D rx_bytes; @@ -480,22 +488,26 @@ int octep_vf_oq_process_rx(struct octep_vf_oq *oq, in= t budget) { u32 pkts_available, pkts_processed, total_pkts_processed; struct octep_vf_device *oct =3D oq->octep_vf_dev; + u32 pkts_pending; =20 pkts_available =3D 0; pkts_processed =3D 0; total_pkts_processed =3D 0; while (total_pkts_processed < budget) { /* update pending count only when current one exhausted */ - if (oq->pkts_pending =3D=3D 0) + pkts_pending =3D READ_ONCE(oq->pkts_pending); + if (pkts_pending =3D=3D 0) octep_vf_oq_check_hw_for_pkts(oct, oq); + pkts_pending =3D READ_ONCE(oq->pkts_pending); pkts_available =3D min(budget - total_pkts_processed, - oq->pkts_pending); + pkts_pending); if (!pkts_available) break; =20 pkts_processed =3D __octep_vf_oq_process_rx(oct, oq, pkts_available); - oq->pkts_pending -=3D pkts_processed; + pkts_pending =3D READ_ONCE(oq->pkts_pending); + WRITE_ONCE(oq->pkts_pending, (pkts_pending - pkts_processed)); total_pkts_processed +=3D pkts_processed; } =20 --=20 2.47.0