From acc7d1bd901cde5acc6891ebc6be6cfc614fb868 Mon Sep 17 00:00:00 2001 From: Jack Morgenstein Date: Mon, 13 Mar 2017 19:29:08 +0200 Subject: [PATCH] net/mlx4_core: Avoid delays during VF driver device shutdown [ Upstream commit 4cbe4dac82e423ecc9a0ba46af24a860853259f4 ] Some Hypervisors detach VFs from VMs by instantly causing an FLR event to be generated for a VF. In the mlx4 case, this will cause that VF's comm channel to be disabled before the VM has an opportunity to invoke the VF device's "shutdown" method. For such Hypervisors, there is a race condition between the VF's shutdown method and its internal-error detection/reset thread. The internal-error detection/reset thread (which runs every 5 seconds) also detects a disabled comm channel. If the internal-error detection/reset flow wins the race, we still get delays (while that flow tries repeatedly to detect comm-channel recovery). The cited commit fixed the command timeout problem when the internal-error detection/reset flow loses the race. This commit avoids the unneeded delays when the internal-error detection/reset flow wins. Fixes: d585df1c5ccf ("net/mlx4_core: Avoid command timeouts during VF driver device shutdown") Signed-off-by: Jack Morgenstein Reported-by: Simon Xiao Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlx4/cmd.c | 11 +++++++++++ drivers/net/ethernet/mellanox/mlx4/main.c | 11 +++++++++++ include/linux/mlx4/device.h | 1 + 3 files changed, 23 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c index d48d5793407d9..fc222df47aa99 100644 --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c @@ -2278,6 +2278,17 @@ static int sync_toggles(struct mlx4_dev *dev) rd_toggle = swab32(readl(&priv->mfunc.comm->slave_read)); if (wr_toggle == 0xffffffff || rd_toggle == 0xffffffff) { /* PCI might be offline */ + + /* If device removal has been requested, + * do not continue retrying. + */ + if (dev->persist->interface_state & + MLX4_INTERFACE_STATE_NOWAIT) { + mlx4_warn(dev, + "communication channel is offline\n"); + return -EIO; + } + msleep(100); wr_toggle = swab32(readl(&priv->mfunc.comm-> slave_write)); diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c index 99361352ed0d0..a7d3144c23883 100644 --- a/drivers/net/ethernet/mellanox/mlx4/main.c +++ b/drivers/net/ethernet/mellanox/mlx4/main.c @@ -1763,6 +1763,14 @@ static int mlx4_comm_check_offline(struct mlx4_dev *dev) (u32)(1 << COMM_CHAN_OFFLINE_OFFSET)); if (!offline_bit) return 0; + + /* If device removal has been requested, + * do not continue retrying. + */ + if (dev->persist->interface_state & + MLX4_INTERFACE_STATE_NOWAIT) + break; + /* There are cases as part of AER/Reset flow that PF needs * around 100 msec to load. We therefore sleep for 100 msec * to allow other tasks to make use of that CPU during this @@ -3690,6 +3698,9 @@ static void mlx4_remove_one(struct pci_dev *pdev) struct mlx4_priv *priv = mlx4_priv(dev); int active_vfs = 0; + if (mlx4_is_slave(dev)) + persist->interface_state |= MLX4_INTERFACE_STATE_NOWAIT; + mutex_lock(&persist->interface_state_mutex); persist->interface_state |= MLX4_INTERFACE_STATE_DELETION; mutex_unlock(&persist->interface_state_mutex); diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h index d3133be12d922..7fde8af9b87ea 100644 --- a/include/linux/mlx4/device.h +++ b/include/linux/mlx4/device.h @@ -460,6 +460,7 @@ enum { enum { MLX4_INTERFACE_STATE_UP = 1 << 0, MLX4_INTERFACE_STATE_DELETION = 1 << 1, + MLX4_INTERFACE_STATE_NOWAIT = 1 << 2, }; #define MSTR_SM_CHANGE_MASK (MLX4_EQ_PORT_INFO_MSTR_SM_SL_CHANGE_MASK | \ -- 2.47.3