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[81.108.45.148]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43d63dec295sm19903643f8f.14.2026.04.11.18.20.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 11 Apr 2026 18:20:01 -0700 (PDT) From: Prathamesh Deshpande To: Leon Romanovsky , Jason Gunthorpe Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, dledford@redhat.com, haggaie@mellanox.com, Prathamesh Deshpande Subject: [PATCH v10 2/2] IB/mlx5: Serialize force-enable state and preserve loopback accounting Date: Sun, 12 Apr 2026 02:18:50 +0100 Message-ID: <20260412011942.13744-3-prathameshdeshpande7@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260412011942.13744-1-prathameshdeshpande7@gmail.com> References: <20260412011942.13744-1-prathameshdeshpande7@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit force_enable is shared between MP bind/unbind flows and regular loopback enable/disable flows. MP helpers updated force_enable without lb.mutex, while regular paths read it under lb.mutex, allowing races and state mismatches. Serialize MP force-enable transitions under lb.mutex. In regular loopback paths, update counters before checking force_enable and roll them back if HW enable fails. Also keep pre-existing master loopback enabled when MP enable fails on the slave side. Use a TD-capability-aware baseline for user_td transitions so threshold checks are correct on both TD-capable and no-TD hardware. Fixes: 08aae7860450 ("RDMA/mlx5: Fix vport loopback forcing for MPV device") Signed-off-by: Prathamesh Deshpande --- drivers/infiniband/hw/mlx5/main.c | 67 +++++++++++++++++++++++++------ 1 file changed, 55 insertions(+), 12 deletions(-) diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c index b3b297bc2f2b..1f11ab443233 100644 --- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -1973,25 +1973,45 @@ static void deallocate_uars(struct mlx5_ib_dev *dev, context->devx_uid); } +static inline u32 mlx5_ib_lb_td_base(struct mlx5_core_dev *mdev) +{ + return MLX5_CAP_GEN(mdev, log_max_transport_domain) ? 1 : 0; +} + static int mlx5_ib_enable_lb_mp(struct mlx5_core_dev *master, struct mlx5_core_dev *slave, struct mlx5_ib_lb_state *lb_state) { + bool user_enabled; int err; + lockdep_assert_held(&mlx5_ib_multiport_mutex); + + mutex_lock(&lb_state->mutex); + if (lb_state->force_enable) { + mutex_unlock(&lb_state->mutex); + return 0; + } + user_enabled = lb_state->enabled; + err = mlx5_nic_vport_update_local_lb(master, true); if (err) - return err; + goto unlock; err = mlx5_nic_vport_update_local_lb(slave, true); if (err) goto out; lb_state->force_enable = true; + lb_state->enabled = true; + mutex_unlock(&lb_state->mutex); return 0; out: - mlx5_nic_vport_update_local_lb(master, false); + if (!user_enabled) + mlx5_nic_vport_update_local_lb(master, false); +unlock: + mutex_unlock(&lb_state->mutex); return err; } @@ -1999,33 +2019,53 @@ static void mlx5_ib_disable_lb_mp(struct mlx5_core_dev *master, struct mlx5_core_dev *slave, struct mlx5_ib_lb_state *lb_state) { - mlx5_nic_vport_update_local_lb(slave, false); - mlx5_nic_vport_update_local_lb(master, false); + u32 td_base = mlx5_ib_lb_td_base(master); + + lockdep_assert_held(&mlx5_ib_multiport_mutex); + + mutex_lock(&lb_state->mutex); + mlx5_nic_vport_update_local_lb(slave, false); lb_state->force_enable = false; + if (lb_state->enabled && + lb_state->user_td <= td_base && lb_state->qps == 0) { + mlx5_nic_vport_update_local_lb(master, false); + lb_state->enabled = false; + } + + mutex_unlock(&lb_state->mutex); } int mlx5_ib_enable_lb(struct mlx5_ib_dev *dev, bool td, bool qp) { + u32 td_base = mlx5_ib_lb_td_base(dev->mdev); int err = 0; - if (dev->lb.force_enable) - return 0; - mutex_lock(&dev->lb.mutex); if (td) dev->lb.user_td++; if (qp) dev->lb.qps++; - if (dev->lb.user_td == 2 || + if (dev->lb.force_enable) + goto unlock; + + if (dev->lb.user_td == td_base + 1 || dev->lb.qps == 1) { if (!dev->lb.enabled) { err = mlx5_nic_vport_update_local_lb(dev->mdev, true); - dev->lb.enabled = true; + if (err) { + if (td) + dev->lb.user_td--; + if (qp) + dev->lb.qps--; + } else { + dev->lb.enabled = true; + } } } +unlock: mutex_unlock(&dev->lb.mutex); return err; @@ -2033,8 +2073,7 @@ int mlx5_ib_enable_lb(struct mlx5_ib_dev *dev, bool td, bool qp) void mlx5_ib_disable_lb(struct mlx5_ib_dev *dev, bool td, bool qp) { - if (dev->lb.force_enable) - return; + u32 td_base = mlx5_ib_lb_td_base(dev->mdev); mutex_lock(&dev->lb.mutex); if (td) @@ -2042,7 +2081,10 @@ void mlx5_ib_disable_lb(struct mlx5_ib_dev *dev, bool td, bool qp) if (qp) dev->lb.qps--; - if (dev->lb.user_td == 1 && + if (dev->lb.force_enable) + goto unlock; + + if (dev->lb.user_td <= td_base && dev->lb.qps == 0) { if (dev->lb.enabled) { mlx5_nic_vport_update_local_lb(dev->mdev, false); @@ -2050,6 +2092,7 @@ void mlx5_ib_disable_lb(struct mlx5_ib_dev *dev, bool td, bool qp) } } +unlock: mutex_unlock(&dev->lb.mutex); } -- 2.43.0