From 31ee5b56c113229247fe41bf7a79d44fe2a7417b Mon Sep 17 00:00:00 2001 From: Jack Morgenstein Date: Tue, 28 Mar 2017 11:55:32 -0400 Subject: [PATCH] net/mlx4_core: Avoid delays during VF driver device shutdown BugLink: http://bugs.launchpad.net/bugs/1672785 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 (cherry picked from commit 4cbe4dac82e423ecc9a0ba46af24a860853259f4) Signed-off-by: Joseph Salisbury Signed-off-by: Tim Gardner --- 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 a49072b4fa52..2710de5a0492 100644 --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c @@ -2304,6 +2304,17 @@ 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 bffa6f345f2f..5428212612c0 100644 --- a/drivers/net/ethernet/mellanox/mlx4/main.c +++ b/drivers/net/ethernet/mellanox/mlx4/main.c @@ -1942,6 +1942,14 @@ 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 @@ -3956,6 +3964,9 @@ static void mlx4_remove_one(struct pci_dev *pdev) struct devlink *devlink = priv_to_devlink(priv); 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 6533c16e27ad..b8d9db3681f9 100644 --- a/include/linux/mlx4/device.h +++ b/include/linux/mlx4/device.h @@ -476,6 +476,7 @@ 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 | \ -- 2.39.5