net/mlx4_core: Return -EPROBE_DEFER when a VF is probed before PF is sufficiently initialized

In the PF initialization, SRIOV is enabled before the PF is fully initialized.
This allows the kernel to probe the newly-exposed VFs before the PF is ready
to handle them (nested probes).

Have the probe method return the -EPROBE_DEFER value in this situation (instead
of the VF probe method retrying its initialization in a loop, and returning -EIO
on failure). When -EPROBE_DEFER is returned by the VF probe method, the kernel
itself will retry the probe after a suitable delay.

Based upon a suggestion by Ben Hutchings <bhutchings@solarflare.com>

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 6 insertions, 16 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c
index 1df56cc50ee9..0e572a527154 100644
--- a/drivers/net/ethernet/mellanox/mlx4/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c
@@ -222,8 +222,6 @@ static int mlx4_comm_cmd_poll(struct mlx4_dev *dev, u8 cmd, u16 param,
                  * FLR process. The only non-zero result in the RESET command
                  * is MLX4_DELAY_RESET_SLAVE*/
                 if ((MLX4_COMM_CMD_RESET == cmd)) {
-                        mlx4_warn(dev, "Got slave FLRed from Communication"
-                                  " channel (ret:0x%x)\n", ret_from_pending);
                         err = MLX4_DELAY_RESET_SLAVE;
                 } else {
                         mlx4_warn(dev, "Communication channel timed out\n");
diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 0d32a82458bf..2f4a26039e80 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -1290,7 +1290,6 @@ static int mlx4_init_slave(struct mlx4_dev *dev)
 {
         struct mlx4_priv *priv = mlx4_priv(dev);
         u64 dma = (u64) priv->mfunc.vhcr_dma;
-        int num_of_reset_retries = NUM_OF_RESET_RETRIES;
         int ret_from_reset = 0;
         u32 slave_read;
         u32 cmd_channel_ver;
@@ -1304,18 +1303,10 @@ static int mlx4_init_slave(struct mlx4_dev *dev)
          * NUM_OF_RESET_RETRIES times before leaving.*/
         if (ret_from_reset) {
                 if (MLX4_DELAY_RESET_SLAVE == ret_from_reset) {
-                        msleep(SLEEP_TIME_IN_RESET);
-                        while (ret_from_reset && num_of_reset_retries) {
-                                mlx4_warn(dev, "slave is currently in the"
-                                          "middle of FLR. retrying..."
-                                          "(try num:%d)\n",
-                                          (NUM_OF_RESET_RETRIES -
-                                           num_of_reset_retries  + 1));
-                                ret_from_reset =
-                                        mlx4_comm_cmd(dev, MLX4_COMM_CMD_RESET,
-                                                      0, MLX4_COMM_TIME);
-                                num_of_reset_retries = num_of_reset_retries - 1;
-                        }
+                        mlx4_warn(dev, "slave is currently in the "
+                                  "middle of FLR. Deferring probe.\n");
+                        mutex_unlock(&priv->cmd.slave_cmd_mutex);
+                        return -EPROBE_DEFER;
                 } else
                         goto err;
         }
@@ -1526,7 +1517,8 @@ static int mlx4_init_hca(struct mlx4_dev *dev)
         } else {
                 err = mlx4_init_slave(dev);
                 if (err) {
-                        mlx4_err(dev, "Failed to initialize slave\n");
+                        if (err != -EPROBE_DEFER)
+                                mlx4_err(dev, "Failed to initialize slave\n");
                         return err;
                 }