RE: [PATCH] bus/pci: don't open uio device in secondary process

[Chaoyong He <chaoyong.he@corigine.com>]

> 
> The uio_pci_generic driver clears the bus master bit when the device file is
> closed.  So, when the secondary process terminates after probing a device,
> that device becomes unusable in the primary process.
> 
> To avoid that, the device file is now opened only in the primary process.  The
> commit that introduced this regression, 847d78fb95
> ("bus/pci: fix FD in secondary process"), only mentioned enabling access to
> config space from secondary process, which still works, as it doesn't rely on
> the device file.

Yes, we can still access the config space from secondary process.

> 
> Fixes: 847d78fb95 ("bus/pci: fix FD in secondary process")

Maybe here also need a 'Cc: stable@dpdk.org' ?

With this, It looks good to me, thanks.
Acked-by: Chaoyong He <chaoyong.he@corigine.com>

> 
> Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
> ---
>  drivers/bus/pci/linux/pci_uio.c | 25 +++++++++++++------------
>  1 file changed, 13 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
> index 4c1d3327a9..432316afcc 100644
> --- a/drivers/bus/pci/linux/pci_uio.c
> +++ b/drivers/bus/pci/linux/pci_uio.c
> @@ -232,18 +232,6 @@ pci_uio_alloc_resource(struct rte_pci_device *dev,
>                         loc->domain, loc->bus, loc->devid, loc->function);
>                 return 1;
>         }
> -       snprintf(devname, sizeof(devname), "/dev/uio%u", uio_num);
> -
> -       /* save fd */
> -       fd = open(devname, O_RDWR);
> -       if (fd < 0) {
> -               PCI_LOG(ERR, "Cannot open %s: %s", devname, strerror(errno));
> -               goto error;
> -       }
> -
> -       if (rte_intr_fd_set(dev->intr_handle, fd))
> -               goto error;
> -
>         snprintf(cfgname, sizeof(cfgname),
>                         "/sys/class/uio/uio%u/device/config", uio_num);
> 
> @@ -273,6 +261,19 @@ pci_uio_alloc_resource(struct rte_pci_device *dev,
>         if (rte_eal_process_type() != RTE_PROC_PRIMARY)
>                 return 0;
> 
> +       /* the uio_pci_generic driver clears the bus master enable bit when the
> device file is
> +        * closed, so open it only in the primary process */
> +       snprintf(devname, sizeof(devname), "/dev/uio%u", uio_num);
> +       /* save fd */
> +       fd = open(devname, O_RDWR);
> +       if (fd < 0) {
> +               PCI_LOG(ERR, "Cannot open %s: %s", devname, strerror(errno));
> +               goto error;
> +       }
> +
> +       if (rte_intr_fd_set(dev->intr_handle, fd))
> +               goto error;
> +
>         /* allocate the mapping details for secondary processes*/
>         *uio_res = rte_zmalloc("UIO_RES", sizeof(**uio_res), 0);
>         if (*uio_res == NULL) {
> --
> 2.45.0