[PATCH v2 03/14] nvmet: Implement CCR nvme command

Mohamed Khalfella
2026-01-30T22:36:27Z

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@purestorage.com>
---
drivers/nvme/target/admin-cmd.c | 74 +++++++++++++++++++++++++++++++++
drivers/nvme/target/core.c | 71 +++++++++++++++++++++++++++++++
drivers/nvme/target/nvmet.h | 13 ++++++
include/linux/nvme.h | 23 ++++++++++
4 files changed, 181 insertions(+)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index ade1145df72d..c0fd8eca2e44 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)
@@ -1615,6 +1617,75 @@ 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(sizeof(*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;
@@ -1692,6 +1763,9 @@ 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 0d2a1206e08f..54dd0dcfa12b 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -114,6 +114,20 @@ 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;
@@ -1396,6 +1410,7 @@ 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;

@@ -1501,6 +1516,38 @@ 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;
+ bool found = false;
+
+ mutex_lock(&subsys->lock);
+ list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
+ if (ctrl->cntlid != cntlid)
+ continue;
+ if (strncmp(ctrl->hostnqn, hostnqn, NVMF_NQN_SIZE))
+ 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))
+ goto out;
+ break;
+ }
+ };
+ ctrl = NULL;
+out:
+ mutex_unlock(&subsys->lock);
+ return ctrl;
+}
+
u16 nvmet_check_ctrl_status(struct nvmet_req *req)
{
if (unlikely(!(req->sq->ctrl->cc & NVME_CC_ENABLE))) {
@@ -1626,6 +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);
@@ -1740,12 +1788,35 @@ 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;
+
+ mutex_lock(&ctrl->lock);
+ nvmet_ctrl_cleanup_ccrs(ctrl, true);
+ mutex_unlock(&ctrl->lock);
+
+ 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);
+ }
+}
+
static void nvmet_ctrl_free(struct kref *ref)
{
struct nvmet_ctrl *ctrl = container_of(ref, struct nvmet_ctrl, ref);
struct nvmet_subsys *subsys = ctrl->subsys;

mutex_lock(&subsys->lock);
+ nvmet_ctrl_complete_pending_ccr(ctrl);
nvmet_ctrl_destroy_pr(ctrl);
nvmet_release_p2p_ns_map(ctrl);
list_del(&ctrl->subsys_entry);
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index f5d9a01ec60c..93d6ac41cf85 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -269,6 +269,7 @@ struct nvmet_ctrl {
u32 kato;
u64 cirn;

+ struct list_head ccr_list;
struct nvmet_port *port;

u32 aen_enabled;
@@ -315,6 +316,13 @@ struct nvmet_ctrl {
struct nvmet_pr_log_mgr pr_log_mgr;
};

+struct nvmet_ccr {
+ struct nvmet_ctrl *ctrl;
+ struct list_head entry;
+ u16 icid;
+ u8 ciu;
+};
+
struct nvmet_subsys {
enum nvme_subsys_type type;

@@ -578,6 +586,7 @@ void nvmet_req_free_sgls(struct nvmet_req *req);
void nvmet_execute_set_features(struct nvmet_req *req);
void nvmet_execute_get_features(struct nvmet_req *req);
void nvmet_execute_keep_alive(struct nvmet_req *req);
+void nvmet_execute_cross_ctrl_reset(struct nvmet_req *req);

u16 nvmet_check_cqid(struct nvmet_ctrl *ctrl, u16 cqid, bool create);
u16 nvmet_check_io_cqid(struct nvmet_ctrl *ctrl, u16 cqid, bool create);
@@ -620,6 +629,10 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args);
struct nvmet_ctrl *nvmet_ctrl_find_get(const char *subsysnqn,
const char *hostnqn, u16 cntlid,
struct nvmet_req *req);
+struct nvmet_ctrl *nvmet_ctrl_find_get_ccr(struct nvmet_subsys *subsys,
+ const char *hostnqn, u8 ciu,
+ u16 cntlid, u64 cirn);
+void nvmet_ctrl_cleanup_ccrs(struct nvmet_ctrl *ctrl, bool all);
void nvmet_ctrl_put(struct nvmet_ctrl *ctrl);
u16 nvmet_check_ctrl_status(struct nvmet_req *req);
ssize_t nvmet_ctrl_host_traddr(struct nvmet_ctrl *ctrl,
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 5135cdc3c120..0f305b317aa3 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -23,6 +23,7 @@

#define NVMF_CQT_MS 0
#define NVMF_CCR_LIMIT 4
+#define NVMF_CCR_PER_PAGE 511

#define NVME_DISC_SUBSYS_NAME "nqn.2014-08.org.nvmexpress.discovery"

@@ -1225,6 +1226,22 @@ struct nvme_zone_mgmt_recv_cmd {
__le32 cdw14[2];
};

+struct nvme_cross_ctrl_reset_cmd {
+ __u8 opcode;
+ __u8 flags;
+ __u16 command_id;
+ __le32 nsid;
+ __le64 rsvd2[2];
+ union nvme_data_ptr dptr;
+ __u8 rsvd10;
+ __u8 ciu;
+ __le16 icid;
+ __le32 cdw11;
+ __le64 cirn;
+ __le32 cdw14;
+ __le32 cdw15;
+};
+
struct nvme_io_mgmt_recv_cmd {
__u8 opcode;
__u8 flags;
@@ -1323,6 +1340,7 @@ enum nvme_admin_opcode {
nvme_admin_virtual_mgmt = 0x1c,
nvme_admin_nvme_mi_send = 0x1d,
nvme_admin_nvme_mi_recv = 0x1e,
+ nvme_admin_cross_ctrl_reset = 0x38,
nvme_admin_dbbuf = 0x7C,
nvme_admin_format_nvm = 0x80,
nvme_admin_security_send = 0x81,
@@ -1356,6 +1374,7 @@ enum nvme_admin_opcode {
nvme_admin_opcode_name(nvme_admin_virtual_mgmt), \
nvme_admin_opcode_name(nvme_admin_nvme_mi_send), \
nvme_admin_opcode_name(nvme_admin_nvme_mi_recv), \
+ nvme_admin_opcode_name(nvme_admin_cross_ctrl_reset), \
nvme_admin_opcode_name(nvme_admin_dbbuf), \
nvme_admin_opcode_name(nvme_admin_format_nvm), \
nvme_admin_opcode_name(nvme_admin_security_send), \
@@ -2009,6 +2028,7 @@ struct nvme_command {
struct nvme_dbbuf dbbuf;
struct nvme_directive_cmd directive;
struct nvme_io_mgmt_recv_cmd imr;
+ struct nvme_cross_ctrl_reset_cmd ccr;
};
};

@@ -2173,6 +2193,9 @@ enum {
NVME_SC_PMR_SAN_PROHIBITED = 0x123,
NVME_SC_ANA_GROUP_ID_INVALID = 0x124,
NVME_SC_ANA_ATTACH_FAILED = 0x125,
+ NVME_SC_CCR_IN_PROGRESS = 0x13f,
+ NVME_SC_CCR_LOGPAGE_FULL = 0x140,
+ NVME_SC_CCR_LIMIT_EXCEEDED = 0x141,

/*
* I/O Command Set Specific - NVM commands:
--
2.52.0