2022-12-08 10:44:53

by Leon Romanovsky

[permalink] [raw]
Subject: Re: [PATCH v5 0/7] Add Auxiliary driver support

On Wed, Dec 07, 2022 at 09:53:03AM -0800, Ajit Khaparde wrote:
> Add auxiliary device driver for Broadcom devices.
> The bnxt_en driver will register and initialize an aux device
> if RDMA is enabled in the underlying device.
> The bnxt_re driver will then probe and initialize the
> RoCE interfaces with the infiniband stack.
>
> We got rid of the bnxt_en_ops which the bnxt_re driver used to
> communicate with bnxt_en.
> Similarly We have tried to clean up most of the bnxt_ulp_ops.
> In most of the cases we used the functions and entry points provided
> by the auxiliary bus driver framework.
> And now these are the minimal functions needed to support the functionality.
>
> We will try to work on getting rid of the remaining if we find any
> other viable option in future.
>
> v1->v2:
> - Incorporated review comments including usage of ulp_id &
> complex function indirections.
> - Used function calls provided by the auxiliary bus interface
> instead of proprietary calls.
> - Refactor code to remove ROCE driver's access to bnxt structure.

I still see wrong usage of auxiliary driver model, especially for RDMA
device. That model mimics general driver model, where you should
separate between device creation and configuration.

I would expect that your bnxt_en create pre-configured devices with
right amount of MSI-X, limits, capabilities e.t.c and RDMA driver will
simply bind to it. It means that calls like bnxt_re_request_msix()
should go too. All PCI-related logic needs to be in netdev.

In addition, I saw IS_ERR_OR_NULL(..) and "if(dev)" checks in various
uninit functions and it can be one of two: wrong unwind flow or wrong
use of driver model. In right implementation, your driver will be called
only on valid device and uninit won't be called for not-initialized device.

Also I spotted .ulp_async_notifier, which is not used and
bnxt_re_sriov_config() is prune to races due to separation between
driver bind and device creation. You should configure SR-IOV in device
creation stage.

Thanks

>
> v2->v3:
> - Addressed review comments including cleanup of some unnecessary wrappers
> - Fixed warnings seen during cross compilation
>
> v3->v4:
> - Cleaned up bnxt_ulp.c and bnxt_ulp.h further
> - Removed some more dead code
> - Sending the patchset as a standalone series
>
> v4->v5:
> - Removed the SRIOV config callback which bnxt_en driver was calling into
> bnxt_re driver.
> - Removed excessive checks for rdev and other pointers.
>
> Please apply. Thanks.
>
> Ajit Khaparde (6):
> bnxt_en: Add auxiliary driver support
> RDMA/bnxt_re: Use auxiliary driver interface
> bnxt_en: Remove usage of ulp_id
> bnxt_en: Use direct API instead of indirection
> bnxt_en: Use auxiliary bus calls over proprietary calls
> RDMA/bnxt_re: Remove the sriov config callback
>
> Hongguang Gao (1):
> bnxt_en: Remove struct bnxt access from RoCE driver
>
> drivers/infiniband/hw/bnxt_re/bnxt_re.h | 9 +-
> drivers/infiniband/hw/bnxt_re/main.c | 591 +++++++-----------
> drivers/net/ethernet/broadcom/bnxt/bnxt.c | 10 +-
> drivers/net/ethernet/broadcom/bnxt/bnxt.h | 8 +
> .../net/ethernet/broadcom/bnxt/bnxt_sriov.c | 7 +-
> drivers/net/ethernet/broadcom/bnxt/bnxt_ulp.c | 413 ++++++------
> drivers/net/ethernet/broadcom/bnxt/bnxt_ulp.h | 53 +-
> 7 files changed, 490 insertions(+), 601 deletions(-)
>
> --
> 2.37.1 (Apple Git-137.1)
>