Re: [PATCH net-next v2] bnxt_en: Allow to set switchdev mode without existing VFs

[Venkat Duvvuru]

> Remove an inability of bnxt_en driver to set eswitch to switchdev
> mode without existing VFs by:
>
> 1. Allow to set switchdev mode in bnxt_dl_eswitch_mode_set() so
>    representors are created only when num_vfs > 0 otherwise just
>    set bp->eswitch_mode
> 2. Do not automatically change bp->eswitch_mode during
>    bnxt_vf_reps_create() and bnxt_vf_reps_destroy() calls so
>    the eswitch mode is managed only by an user by devlink.
>    Just set temporarily bp->eswitch_mode to legacy to avoid
>    re-opening of representors during destroy.
> 3. Create representors in bnxt_sriov_enable() if current eswitch
>    mode is switchdev one
>
> Tested by this sequence:
> 1. Set PF interface up
> 2. Set PF's eswitch mode to switchdev
> 3. Created N VFs
> 4. Checked that N representors were created
> 5. Set eswitch mode to legacy
> 6. Checked that representors were deleted
> 7. Set eswitch mode back to switchdev
> 8. Checked that representors exist again for VFs
> 9. Deleted all VFs
> 10. Checked that all representors were deleted as well
> 11. Checked that current eswitch mode is still switchdev
>
> Signed-off-by: Ivan Vecera <ivecera@xxxxxxxxxx>
> ---
>  .../net/ethernet/broadcom/bnxt/bnxt_sriov.c   | 16 ++++++++++
>  drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c | 29 ++++++++++++-------
>  drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.h |  6 ++++
>  3 files changed, 41 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_sriov.c
> b/drivers/net/ethernet/broadcom/bnxt/bnxt_sriov.c
> index 3ed3a2b3b3a9..dde327f2c57e 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_sriov.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_sriov.c
> @@ -825,8 +825,24 @@ static int bnxt_sriov_enable(struct bnxt *bp, int *num_vfs)
>         if (rc)
>                 goto err_out2;
>
> +       if (bp->eswitch_mode != DEVLINK_ESWITCH_MODE_SWITCHDEV)
> +               return 0;
> +
> +       /* Create representors for VFs in switchdev mode */
> +       devl_lock(bp->dl);
> +       rc = bnxt_vf_reps_create(bp);
> +       devl_unlock(bp->dl);
> +       if (rc) {
> +               netdev_info(bp->dev, "Cannot enable VFS as
> representors cannot be created\n");
> +               goto err_out3;
> +       }
> +
>         return 0;
>
> +err_out3:
> +       /* Disable SR-IOV */
> +       pci_disable_sriov(bp->pdev);
> +
>  err_out2:
>         /* Free the resources reserved for various VF's */
>         bnxt_hwrm_func_vf_resource_free(bp, *num_vfs);
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c
> b/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c
> index fcc65890820a..2f1a1f2d2157 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c
> @@ -356,10 +356,15 @@ void bnxt_vf_reps_destroy(struct bnxt *bp)
>         /* un-publish cfa_code_map so that RX path can't see it anymore */
>         kfree(bp->cfa_code_map);
>         bp->cfa_code_map = NULL;
> -       bp->eswitch_mode = DEVLINK_ESWITCH_MODE_LEGACY;
>
> -       if (closed)
> +       if (closed) {
> +               /* Temporarily set legacy mode to avoid re-opening
> +                * representors and restore switchdev mode after that.
> +                */
> +               bp->eswitch_mode = DEVLINK_ESWITCH_MODE_LEGACY;
>                 bnxt_open_nic(bp, false, false);
> +               bp->eswitch_mode = DEVLINK_ESWITCH_MODE_SWITCHDEV;
> +       }
>         rtnl_unlock();
>
>         /* Need to call vf_reps_destroy() outside of rntl_lock
> @@ -482,7 +487,7 @@ static void bnxt_vf_rep_netdev_init(struct bnxt
> *bp, struct bnxt_vf_rep *vf_rep,
>         dev->min_mtu = ETH_ZLEN;
>  }
>
> -static int bnxt_vf_reps_create(struct bnxt *bp)
> +int bnxt_vf_reps_create(struct bnxt *bp)
>  {
>         u16 *cfa_code_map = NULL, num_vfs = pci_num_vf(bp->pdev);
>         struct bnxt_vf_rep *vf_rep;
> @@ -535,7 +540,6 @@ static int bnxt_vf_reps_create(struct bnxt *bp)
>
>         /* publish cfa_code_map only after all VF-reps have been initialized */
>         bp->cfa_code_map = cfa_code_map;
> -       bp->eswitch_mode = DEVLINK_ESWITCH_MODE_SWITCHDEV;
>         netif_keep_dst(bp->dev);
>         return 0;
>
> @@ -559,6 +563,7 @@ int bnxt_dl_eswitch_mode_set(struct devlink
> *devlink, u16 mode,
>                              struct netlink_ext_ack *extack)
>  {
>         struct bnxt *bp = bnxt_get_bp_from_dl(devlink);
> +       int ret = 0;
>
>         if (bp->eswitch_mode == mode) {
>                 netdev_info(bp->dev, "already in %s eswitch mode\n",
> @@ -570,7 +575,7 @@ int bnxt_dl_eswitch_mode_set(struct devlink
> *devlink, u16 mode,
>         switch (mode) {
>         case DEVLINK_ESWITCH_MODE_LEGACY:
>                 bnxt_vf_reps_destroy(bp);
> -               return 0;
> +               break;
>
>         case DEVLINK_ESWITCH_MODE_SWITCHDEV:
>                 if (bp->hwrm_spec_code < 0x10803) {
> @@ -578,15 +583,19 @@ int bnxt_dl_eswitch_mode_set(struct devlink
> *devlink, u16 mode,
>                         return -ENOTSUPP;
>                 }
>
> -               if (pci_num_vf(bp->pdev) == 0) {
> -                       netdev_info(bp->dev, "Enable VFs before
> setting switchdev mode\n");
> -                       return -EPERM;
> -               }
> -               return bnxt_vf_reps_create(bp);
> +               /* Create representors for existing VFs */
> +               if (pci_num_vf(bp->pdev) > 0)
> +                       ret = bnxt_vf_reps_create(bp);
> +               break;
>
>         default:
>                 return -EINVAL;
>         }
> +
> +       if (!ret)
> +               bp->eswitch_mode = mode;
> +
> +       return ret;
>  }
>
>  #endif
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.h
> b/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.h
> index 5637a84884d7..33a965631d0b 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.h
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.h
> @@ -14,6 +14,7 @@
>
>  #define        MAX_CFA_CODE                    65536
>
> +int bnxt_vf_reps_create(struct bnxt *bp);
>  void bnxt_vf_reps_destroy(struct bnxt *bp);
>  void bnxt_vf_reps_close(struct bnxt *bp);
>  void bnxt_vf_reps_open(struct bnxt *bp);
> @@ -37,6 +38,11 @@ int bnxt_dl_eswitch_mode_set(struct devlink
> *devlink, u16 mode,
>
>  #else
>
> +static inline int bnxt_vf_reps_create(struct bnxt *bp)
> +{
> +       return 0;
> +}
> +
>  static inline void bnxt_vf_reps_close(struct bnxt *bp)
>  {
>  }
> --
> 2.39.2
ACK

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