Re: [PATCH v2] nvme: allow 64-bit results in passthru commands
From: Christoph Hellwig
Date: Wed Aug 21 2019 - 20:09:38 EST
On Fri, Aug 16, 2019 at 11:47:21AM +0200, Marta Rybczynska wrote:
> It is not possible to get 64-bit results from the passthru commands,
> what prevents from getting for the Capabilities (CAP) property value.
>
> As a result, it is not possible to implement IOL's NVMe Conformance
> test 4.3 Case 1 for Fabrics targets [1] (page 123).
>
> This issue has been already discussed [2], but without a solution.
>
> This patch solves the problem by adding new ioctls with a new
> passthru structure, including 64-bit results. The older ioctls stay
> unchanged.
Ok, with my idea not being suitable I think I'm fine with this approach, a
little nitpick below:
> +static bool is_admin_cmd(unsigned int cmd)
> +{
> + if ((cmd == NVME_IOCTL_ADMIN_CMD) || (cmd == NVME_IOCTL_ADMIN64_CMD))
> + return true;
> + return false;
> +}
No need for the inner braces. But I'm actually not sure the current
code structure is very suitable for extending it.
> +
> static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
> unsigned int cmd, unsigned long arg)
> {
> @@ -1418,13 +1473,13 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
> * seperately and drop the ns SRCU reference early. This avoids a
> * deadlock when deleting namespaces using the passthrough interface.
> */
> - if (cmd == NVME_IOCTL_ADMIN_CMD || is_sed_ioctl(cmd)) {
> + if (is_admin_cmd(cmd) || is_sed_ioctl(cmd)) {
So maybe for this check we should have a is_ctrl_iocl() helper instead
that includes the is_sed_ioctl check.
> struct nvme_ctrl *ctrl = ns->ctrl;
>
> nvme_get_ctrl(ns->ctrl);
> nvme_put_ns_from_disk(head, srcu_idx);
>
> - if (cmd == NVME_IOCTL_ADMIN_CMD)
> + if (is_admin_cmd(cmd))
> ret = nvme_user_cmd(ctrl, NULL, argp);
> else
> ret = sed_ioctl(ctrl->opal_dev, cmd, argp);
And then we can move this whole branch into a helper function,
which then switches on the ioctl cmd, with sed_ioctl as the fallback.