net/mlx5: Fix return code in case of hyperv wrong size read

Return code value could be non deterministic in case of wrong size read.
With this patch, if such error occurs, set rc to be -EIO.

In addition, mlx5_hv_config_common() supports reading of
HV_CONFIG_BLOCK_SIZE_MAX bytes only, fix to early return error with
bad input.

Fixes: 913d14e86657 ("net/mlx5: Add wrappers for HyperV PCIe operations")
Reported-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c
index cf08d02703fb5d18fd34ccf215bdfb8dcf1de85c..583dc7e2aca8f208ba6d5b02c6b3521758a149fd 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c
@@ -12,7 +12,7 @@ static int mlx5_hv_config_common(struct mlx5_core_dev *dev, void *buf, int len,
        int bytes_returned;
        int block_id;
 
-       if (offset % HV_CONFIG_BLOCK_SIZE_MAX || len % HV_CONFIG_BLOCK_SIZE_MAX)
+       if (offset % HV_CONFIG_BLOCK_SIZE_MAX || len != HV_CONFIG_BLOCK_SIZE_MAX)
                return -EINVAL;
 
        block_id = offset / HV_CONFIG_BLOCK_SIZE_MAX;
@@ -25,8 +25,8 @@ static int mlx5_hv_config_common(struct mlx5_core_dev *dev, void *buf, int len,
                                  HV_CONFIG_BLOCK_SIZE_MAX, block_id);
 
        /* Make sure len bytes were read successfully  */
-       if (read)
-               rc |= !(len == bytes_returned);
+       if (read && !rc && len != bytes_returned)
+               rc = -EIO;
 
        if (rc) {
                mlx5_core_err(dev, "Failed to %s hv config, err = %d, len = %d, offset = %d\n",