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.

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

Signed-off-by: Konrad Sztyber <konrad.szty...@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

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