Re: [PATCH v1 4/7] fpga: dfl: fix VF creation when ports have no local BAR space

Tom Rix
2022-02-15T15:50:53Z

On 2/14/22 3:26 AM, Tianfei zhang wrote:
> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>
> When a port is not connected to the same PCIe endpoint as
> the FME, the port does not need to be released before being
> virtualized. Fix VF creation code to handle this new use
Similar, how does this fit in with iofs, this looks like it would not be
valid for the existing cards
> case.
>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> Signed-off-by: Tianfei Zhang <tianfei.zhang@intel.com>
> ---
> drivers/fpga/dfl.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index 26f8cf890700..cfc539a656f0 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -1705,15 +1705,22 @@ EXPORT_SYMBOL_GPL(dfl_fpga_cdev_config_ports_pf);
> int dfl_fpga_cdev_config_ports_vf(struct dfl_fpga_cdev *cdev, int num_vfs)
> {
> struct dfl_feature_platform_data *pdata;
> - int ret = 0;
> + int ret = 0, port_count = 0;
>
> mutex_lock(&cdev->lock);
> +
> + list_for_each_entry(pdata, &cdev->port_dev_list, node) {
> + if (pdata->dev)

This looks wrong,

pdata->dev is dereferenced below, if there is a case were (!pdata->dev)
here there would be crash later.

> + continue;
> + port_count++;

how does this work when only some of the ports are handled in the new way ?

Tom

> + }
> +
> /*
> * can't turn multiple ports into 1 VF device, only 1 port for 1 VF
> * device, so if released port number doesn't match VF device number,
> * then reject the request with -EINVAL error code.
> */
> - if (cdev->released_port_num != num_vfs) {
> + if (port_count && cdev->released_port_num != num_vfs) {
> ret = -EINVAL;
> goto done;
> }