Re: [PATCH v4 03/15] nvmet: Implement CCR nvme command
From: Hannes Reinecke
Date: Mon Mar 30 2026 - 06:47:12 EST
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@xxxxxxxxxxxxxxx>
---
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@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich