[PATCH v4 03/15] nvmet: Implement CCR nvme command
Hannes Reinecke
hare at suse.de
Mon Mar 30 03:45:57 PDT 2026
On 3/28/26 01:43, Mohamed Khalfella wrote:
> Defined by TP8028 Rapid Path Failure Recovery, CCR (Cross-Controller
> Reset) command is an nvme command issued to source controller by
> initiator to reset impacted controller. Implement CCR command for linux
> nvme target.
>
> Signed-off-by: Mohamed Khalfella <mkhalfella at purestorage.com>
> ---
> drivers/nvme/target/admin-cmd.c | 74 ++++++++++++++++++++++++++++++++
> drivers/nvme/target/core.c | 76 +++++++++++++++++++++++++++++++++
> drivers/nvme/target/nvmet.h | 13 ++++++
> include/linux/nvme.h | 23 ++++++++++
> 4 files changed, 186 insertions(+)
>
> diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
> index ec09e30eca18..0a37c0eeebb5 100644
> --- a/drivers/nvme/target/admin-cmd.c
> +++ b/drivers/nvme/target/admin-cmd.c
> @@ -376,7 +376,9 @@ static void nvmet_get_cmd_effects_admin(struct nvmet_ctrl *ctrl,
> log->acs[nvme_admin_get_features] =
> log->acs[nvme_admin_async_event] =
> log->acs[nvme_admin_keep_alive] =
> + log->acs[nvme_admin_cross_ctrl_reset] =
> cpu_to_le32(NVME_CMD_EFFECTS_CSUPP);
> +
> }
>
> static void nvmet_get_cmd_effects_nvm(struct nvme_effects_log *log)
> @@ -1613,6 +1615,75 @@ void nvmet_execute_keep_alive(struct nvmet_req *req)
> nvmet_req_complete(req, status);
> }
>
> +void nvmet_execute_cross_ctrl_reset(struct nvmet_req *req)
> +{
> + struct nvmet_ctrl *ictrl, *sctrl = req->sq->ctrl;
> + struct nvme_command *cmd = req->cmd;
> + struct nvmet_ccr *ccr, *new_ccr;
> + int ccr_active, ccr_total;
> + u16 cntlid, status = NVME_SC_SUCCESS;
> +
> + cntlid = le16_to_cpu(cmd->ccr.icid);
> + if (sctrl->cntlid == cntlid) {
> + req->error_loc =
> + offsetof(struct nvme_cross_ctrl_reset_cmd, icid);
> + status = NVME_SC_INVALID_FIELD | NVME_STATUS_DNR;
> + goto out;
> + }
> +
> + /* Find and get impacted controller */
> + ictrl = nvmet_ctrl_find_get_ccr(sctrl->subsys, sctrl->hostnqn,
> + cmd->ccr.ciu, cntlid,
> + le64_to_cpu(cmd->ccr.cirn));
> + if (!ictrl) {
> + /* Immediate Reset Successful */
> + nvmet_set_result(req, 1);
> + status = NVME_SC_SUCCESS;
> + goto out;
> + }
> +
> + ccr_total = ccr_active = 0;
> + mutex_lock(&sctrl->lock);
> + list_for_each_entry(ccr, &sctrl->ccr_list, entry) {
> + if (ccr->ctrl == ictrl) {
> + status = NVME_SC_CCR_IN_PROGRESS | NVME_STATUS_DNR;
> + goto out_unlock;
> + }
> +
> + ccr_total++;
> + if (ccr->ctrl)
> + ccr_active++;
> + }
> +
> + if (ccr_active >= NVMF_CCR_LIMIT) {
> + status = NVME_SC_CCR_LIMIT_EXCEEDED;
> + goto out_unlock;
> + }
> + if (ccr_total >= NVMF_CCR_PER_PAGE) {
> + status = NVME_SC_CCR_LOGPAGE_FULL;
> + goto out_unlock;
> + }
> +
> + new_ccr = kmalloc_obj(*new_ccr, GFP_KERNEL);
> + if (!new_ccr) {
> + status = NVME_SC_INTERNAL;
> + goto out_unlock;
> + }
> +
> + new_ccr->ciu = cmd->ccr.ciu;
> + new_ccr->icid = cntlid;
> + new_ccr->ctrl = ictrl;
> + list_add_tail(&new_ccr->entry, &sctrl->ccr_list);
> +
> +out_unlock:
> + mutex_unlock(&sctrl->lock);
> + if (status == NVME_SC_SUCCESS)
> + nvmet_ctrl_fatal_error(ictrl);
> + nvmet_ctrl_put(ictrl);
> +out:
> + nvmet_req_complete(req, status);
> +}
> +
> u32 nvmet_admin_cmd_data_len(struct nvmet_req *req)
> {
> struct nvme_command *cmd = req->cmd;
> @@ -1690,6 +1761,9 @@ u16 nvmet_parse_admin_cmd(struct nvmet_req *req)
> case nvme_admin_keep_alive:
> req->execute = nvmet_execute_keep_alive;
> return 0;
> + case nvme_admin_cross_ctrl_reset:
> + req->execute = nvmet_execute_cross_ctrl_reset;
> + return 0;
> default:
> return nvmet_report_invalid_opcode(req);
> }
> diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
> index e8b945a01f35..2e0c31d82bad 100644
> --- a/drivers/nvme/target/core.c
> +++ b/drivers/nvme/target/core.c
> @@ -117,6 +117,20 @@ u16 nvmet_zero_sgl(struct nvmet_req *req, off_t off, size_t len)
> return 0;
> }
>
> +void nvmet_ctrl_cleanup_ccrs(struct nvmet_ctrl *ctrl, bool all)
> +{
> + struct nvmet_ccr *ccr, *tmp;
> +
> + lockdep_assert_held(&ctrl->lock);
> +
> + list_for_each_entry_safe(ccr, tmp, &ctrl->ccr_list, entry) {
> + if (all || ccr->ctrl == NULL) {
> + list_del(&ccr->entry);
> + kfree(ccr);
> + }
> + }
> +}
> +
> static u32 nvmet_max_nsid(struct nvmet_subsys *subsys)
> {
> struct nvmet_ns *cur;
> @@ -1399,6 +1413,7 @@ static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
> if (!nvmet_is_disc_subsys(ctrl->subsys)) {
> ctrl->ciu = ((u8)(ctrl->ciu + 1)) ? : 1;
> ctrl->cirn = get_random_u64();
> + nvmet_ctrl_cleanup_ccrs(ctrl, false);
> }
> ctrl->csts = NVME_CSTS_RDY;
>
> @@ -1504,6 +1519,35 @@ struct nvmet_ctrl *nvmet_ctrl_find_get(const char *subsysnqn,
> return ctrl;
> }
>
> +struct nvmet_ctrl *nvmet_ctrl_find_get_ccr(struct nvmet_subsys *subsys,
> + const char *hostnqn, u8 ciu,
> + u16 cntlid, u64 cirn)
> +{
> + struct nvmet_ctrl *ctrl, *ictrl = NULL;
> + bool found = false;
> +
> + mutex_lock(&subsys->lock);
> + list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
> + if (ctrl->cntlid != cntlid)
> + continue;
> +
> + /* Avoid racing with a controller that is becoming ready */
> + mutex_lock(&ctrl->lock);
> + if (ctrl->ciu == ciu && ctrl->cirn == cirn)
> + found = true;
> + mutex_unlock(&ctrl->lock);
> +
> + if (found) {
> + if (kref_get_unless_zero(&ctrl->ref))
> + ictrl = ctrl;
> + break;
> + }
> + };
> + mutex_unlock(&subsys->lock);
> +
> + return ictrl;
> +}
> +
> u16 nvmet_check_ctrl_status(struct nvmet_req *req)
> {
> if (unlikely(!(req->sq->ctrl->cc & NVME_CC_ENABLE))) {
> @@ -1629,6 +1673,7 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args)
> subsys->clear_ids = 1;
> #endif
>
> + INIT_LIST_HEAD(&ctrl->ccr_list);
> INIT_WORK(&ctrl->async_event_work, nvmet_async_event_work);
> INIT_LIST_HEAD(&ctrl->async_events);
> INIT_RADIX_TREE(&ctrl->p2p_ns_map, GFP_KERNEL);
> @@ -1739,12 +1784,43 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args)
> }
> EXPORT_SYMBOL_GPL(nvmet_alloc_ctrl);
>
> +static void nvmet_ctrl_complete_pending_ccr(struct nvmet_ctrl *ctrl)
> +{
> + struct nvmet_subsys *subsys = ctrl->subsys;
> + struct nvmet_ctrl *sctrl;
> + struct nvmet_ccr *ccr;
> +
> + lockdep_assert_held(&subsys->lock);
> +
> + /* Cleanup all CCRs issued by ctrl as source controller */
> + mutex_lock(&ctrl->lock);
> + nvmet_ctrl_cleanup_ccrs(ctrl, true);
> + mutex_unlock(&ctrl->lock);
> +
> + /*
> + * Find all CCRs targeting ctrl as impacted controller and
> + * set ccr->ctrl to NULL. This tells the source controller
> + * that CCR completed successfully.
> + */
> + list_for_each_entry(sctrl, &subsys->ctrls, subsys_entry) {
> + mutex_lock(&sctrl->lock);
> + list_for_each_entry(ccr, &sctrl->ccr_list, entry) {
> + if (ccr->ctrl == ctrl) {
> + ccr->ctrl = NULL;
> + break;
> + }
> + }
> + mutex_unlock(&sctrl->lock);
> + }
> +}
> +
Do I see this correct that with this implementation a CCR is only
complete once the controller resets? IOW the CCR has to wait for
the controller to be reset, but it does not invoke a controller reset
itself?
Is that intended?
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare at suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
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