Re: [PATCH 4/5] cxl/mbox: Use new return_code handling

[Dan Williams <dan.j.williams@intel.com>]

On Thu, Mar 17, 2022 at 4:41 PM Davidlohr Bueso <dave@stgolabs.net> wrote:
>
> Use the global cxl_mbox_cmd_rc table to improve debug messaging
> in __cxl_pci_mbox_send_cmd() and allow cxl_mbox_send_cmd()
> to map to proper kernel style errno codes - this patch
> continues to use -ENXIO only so no change in semantics.
>
> Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
> ---
>  drivers/cxl/core/mbox.c | 7 ++++---
>  drivers/cxl/pci.c       | 3 ++-
>  2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index d4d4a16820b7..fa9e7043f158 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -170,9 +170,10 @@ int cxl_mbox_send_cmd(struct cxl_dev_state *cxlds, u16 opcode, void *in,
>         if (rc)
>                 return rc;
>
> -       /* TODO: Map return code to proper kernel style errno */
> -       if (mbox_cmd.return_code != CXL_MBOX_CMD_RC_SUCCESS)
> -               return -ENXIO;
> +       if (mbox_cmd.return_code != CXL_MBOX_CMD_RC_SUCCESS) {
> +               int err = cxl_mbox_cmd_rc2errno(&mbox_cmd);
> +               return -err;

I don't like the need for a local variable and adding the negation.
Just store the negative value directly and call the helper
cxl_mbox_cmd_rc2err() so that this can just do "return
cxl_mbox_cmd_rc2err(&mbox_cmd);".

> +       }
>
>         /*
>          * Variable sized commands can't be validated and so it's up to the
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 0c36d111232b..67ec0220826f 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -178,7 +178,8 @@ static int __cxl_pci_mbox_send_cmd(struct cxl_dev_state *cxlds,
>                 FIELD_GET(CXLDEV_MBOX_STATUS_RET_CODE_MASK, status_reg);
>
>         if (mbox_cmd->return_code != CXL_MBOX_CMD_RC_SUCCESS) {
> -               dev_dbg(dev, "Mailbox operation had an error\n");
> +               dev_dbg(dev, "Mailbox operation had an error: %s\n",
> +                       cxl_mbox_cmd_rc2str(mbox_cmd));

Looks good.