On 12/6/2022 9:26 AM, Huisong Li wrote:
> The driver assignment was moved back at the end of the device probing
> because there is no something to use rte_driver during the phase of
> probing. See commit 391797f04208 ("drivers/bus: move driver assignment
> to end of probing")
>
> However, it is necessary for probing callback to reference rte_driver
> before probing. For example, probing callback may call some APIs which
> access the rte_pci_driver::driver by the device::driver pointer to get
> driver information. In this case, a segment fault will occur in probing
> callback if there is not this assignment.
>
Probing callback gets driver as parameter, so callback function can
access it via 'drv->driver', is there a specific usecase that
'dev->device->driver' needs to be accessed explicitly?
I assume this is related to coming patches that setting up device in
testpmd event callback, but can you please clarify exact need.
> Further, some comments in code need to be updated if we do that. The
> driver pointer in rte_device is set before probing and needs to be reset
> if probing failed. And rte_dev_is_probed can not be called inside probing.
>
> Fixes: 391797f04208 ("drivers/bus: move driver assignment to end of probing")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Huisong Li <lihuis...@huawei.com>
> ---
> drivers/bus/auxiliary/auxiliary_common.c | 9 +++++++--
> drivers/bus/dpaa/dpaa_bus.c | 9 +++++++--
> drivers/bus/fslmc/fslmc_bus.c | 8 +++++++-
> drivers/bus/ifpga/ifpga_bus.c | 12 +++++++++---
> drivers/bus/pci/pci_common.c | 9 +++++++--
> drivers/bus/vdev/vdev.c | 10 ++++++++--
> drivers/bus/vmbus/vmbus_common.c | 9 +++++++--
> 7 files changed, 52 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/bus/auxiliary/auxiliary_common.c
> b/drivers/bus/auxiliary/auxiliary_common.c
> index ff1369353a..13cb3fe0f8 100644
> --- a/drivers/bus/auxiliary/auxiliary_common.c
> +++ b/drivers/bus/auxiliary/auxiliary_common.c
> @@ -132,16 +132,21 @@ rte_auxiliary_probe_one_driver(struct
> rte_auxiliary_driver *drv,
> }
>
> dev->driver = drv;
> + /*
> + * Reference rte_driver before probing so as to this pointer can
> + * be used to get driver information in case of segment fault in
> + * probing callback.
> + */
> + dev->device.driver = &drv->driver;
>
> AUXILIARY_LOG(INFO, "Probe auxiliary driver: %s device: %s (NUMA node
> %i)",
> drv->driver.name, dev->name, dev->device.numa_node);
> ret = drv->probe(drv, dev);
> if (ret != 0) {
> dev->driver = NULL;
> + dev->device.driver = NULL;
> rte_intr_instance_free(dev->intr_handle);
> dev->intr_handle = NULL;
> - } else {
> - dev->device.driver = &drv->driver;
> }
>
> return ret;
> diff --git a/drivers/bus/dpaa/dpaa_bus.c b/drivers/bus/dpaa/dpaa_bus.c
> index e57159f5d8..f1b817e58c 100644
> --- a/drivers/bus/dpaa/dpaa_bus.c
> +++ b/drivers/bus/dpaa/dpaa_bus.c
> @@ -693,17 +693,22 @@ rte_dpaa_bus_probe(void)
> (dev->device.devargs &&
> dev->device.devargs->policy == RTE_DEV_BLOCKED))
> continue;
> -
> + /*
> + * Reference rte_driver before probing so as to this
> + * pointer can be used to get driver information in case
> + * of segment fault in probing callback.
> + */
> + dev->device.driver = &drv->driver;
> if (probe_all ||
> (dev->device.devargs &&
> dev->device.devargs->policy == RTE_DEV_ALLOWED)) {
> ret = drv->probe(drv, dev);
> if (ret) {
> + dev->device.driver = NULL;
> DPAA_BUS_ERR("unable to probe:%s",
> dev->name);
> } else {
> dev->driver = drv;
> - dev->device.driver = &drv->driver;
> }
> }
> break;
> diff --git a/drivers/bus/fslmc/fslmc_bus.c b/drivers/bus/fslmc/fslmc_bus.c
> index 57bfb5111a..4bc0c6d3d4 100644
> --- a/drivers/bus/fslmc/fslmc_bus.c
> +++ b/drivers/bus/fslmc/fslmc_bus.c
> @@ -471,15 +471,21 @@ rte_fslmc_probe(void)
> continue;
> }
>
> + /*
> + * Reference rte_driver before probing so as to this
> + * pointer can be used to get driver information in case
> + * of segment fault in probing callback.
> + */
> + dev->device.driver = &drv->driver;
> if (probe_all ||
> (dev->device.devargs &&
> dev->device.devargs->policy == RTE_DEV_ALLOWED)) {
> ret = drv->probe(drv, dev);
> if (ret) {
> + dev->device.driver = NULL;
> DPAA2_BUS_ERR("Unable to probe");
> } else {
> dev->driver = drv;
> - dev->device.driver = &drv->driver;
> }
> }
> break;
> diff --git a/drivers/bus/ifpga/ifpga_bus.c b/drivers/bus/ifpga/ifpga_bus.c
> index bb943b58b5..5f23446f41 100644
> --- a/drivers/bus/ifpga/ifpga_bus.c
> +++ b/drivers/bus/ifpga/ifpga_bus.c
> @@ -293,13 +293,19 @@ ifpga_probe_one_driver(struct rte_afu_driver *drv,
>
> /* reference driver structure */
> afu_dev->driver = drv;
> + /*
> + * Reference rte_driver before probing so as to this pointer can
> + * be used to get driver information in case of segment fault in
> + * probing callback.
> + */
> + afu_dev->device.driver = &drv->driver;
>
> /* call the driver probe() function */
> ret = drv->probe(afu_dev);
> - if (ret)
> + if (ret) {
> afu_dev->driver = NULL;
> - else
> - afu_dev->device.driver = &drv->driver;
> + afu_dev->device.driver = NULL;
> + }
>
> return ret;
> }
> diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
> index bc3a7f39fe..efaa1792e9 100644
> --- a/drivers/bus/pci/pci_common.c
> +++ b/drivers/bus/pci/pci_common.c
> @@ -302,6 +302,12 @@ rte_pci_probe_one_driver(struct rte_pci_driver *dr,
> return ret;
> }
> }
> + /*
> + * Reference rte_driver before probing so as to this pointer can
> + * be used to get driver information in case of segment fault in
> + * probing callback.
> + */
> + dev->device.driver = &dr->driver;
> }
>
> RTE_LOG(INFO, EAL, "Probe PCI driver: %s (%x:%x) device: "PCI_PRI_FMT"
> (socket %i)\n",
> @@ -314,6 +320,7 @@ rte_pci_probe_one_driver(struct rte_pci_driver *dr,
> return ret; /* no rollback if already succeeded earlier */
> if (ret) {
> dev->driver = NULL;
> + dev->device.driver = NULL;
> if ((dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING) &&
> /* Don't unmap if device is unsupported and
> * driver needs mapped resources.
> @@ -325,8 +332,6 @@ rte_pci_probe_one_driver(struct rte_pci_driver *dr,
> dev->vfio_req_intr_handle = NULL;
> rte_intr_instance_free(dev->intr_handle);
> dev->intr_handle = NULL;
> - } else {
> - dev->device.driver = &dr->driver;
> }
>
> return ret;
> diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
> index 41bc07dde7..2e3f0f2e12 100644
> --- a/drivers/bus/vdev/vdev.c
> +++ b/drivers/bus/vdev/vdev.c
> @@ -207,9 +207,15 @@ vdev_probe_all_drivers(struct rte_vdev_device *dev)
> return -1;
> }
>
> + /*
> + * Reference rte_driver before probing so as to this pointer can
> + * be used to get driver information in case of segment fault in
> + * probing callback.
> + */
> + dev->device.driver = &driver->driver;
> ret = driver->probe(dev);
> - if (ret == 0)
> - dev->device.driver = &driver->driver;
> + if (ret != 0)
> + dev->device.driver = NULL;
> return ret;
> }
>
> diff --git a/drivers/bus/vmbus/vmbus_common.c
> b/drivers/bus/vmbus/vmbus_common.c
> index 8d32d66504..feb1651984 100644
> --- a/drivers/bus/vmbus/vmbus_common.c
> +++ b/drivers/bus/vmbus/vmbus_common.c
> @@ -110,6 +110,12 @@ vmbus_probe_one_driver(struct rte_vmbus_driver *dr,
>
> /* reference driver structure */
> dev->driver = dr;
> + /*
> + * Reference rte_driver before probing so as to this pointer can
> + * be used to get driver information in case of segment fault in
> + * probing callback.
> + */
> + dev->device.driver = &dr->driver;
>
> if (dev->device.numa_node < 0 && rte_socket_count() > 1)
> VMBUS_LOG(INFO, "Device %s is not NUMA-aware", guid);
> @@ -119,9 +125,8 @@ vmbus_probe_one_driver(struct rte_vmbus_driver *dr,
> ret = dr->probe(dr, dev);
> if (ret) {
> dev->driver = NULL;
> + dev->device.driver = NULL;
> rte_vmbus_unmap_device(dev);
> - } else {
> - dev->device.driver = &dr->driver;
> }
>
> return ret;
