[PATCH V4 1/1] nvmet: support reservation feature
Sagi Grimberg
sagi at grimberg.me
Mon Jan 22 05:03:43 PST 2024
> This patch implements the reservation feature, includes:
> 1. reservation register(register, unregister and replace).
> 2. reservation acquire(acquire, preempt, preempt and abort).
> 3. reservation release(release and clear).
> 4. reservation report.
>
> And also make reservation configurable, one can set ns to support
> reservation before enable ns. The default of resv_enable is false.
>
> Signed-off-by: Guixin Liu <kanie at linux.alibaba.com>
> ---
> drivers/nvme/target/Makefile | 2 +-
> drivers/nvme/target/admin-cmd.c | 14 +-
> drivers/nvme/target/configfs.c | 27 +
> drivers/nvme/target/core.c | 50 +-
> drivers/nvme/target/nvmet.h | 35 ++
> drivers/nvme/target/pr.c | 956 ++++++++++++++++++++++++++++++++
> include/linux/nvme.h | 48 ++
> 7 files changed, 1125 insertions(+), 7 deletions(-)
> create mode 100644 drivers/nvme/target/pr.c
>
> diff --git a/drivers/nvme/target/Makefile b/drivers/nvme/target/Makefile
> index c66820102493..f9bfc904a5b3 100644
> --- a/drivers/nvme/target/Makefile
> +++ b/drivers/nvme/target/Makefile
> @@ -10,7 +10,7 @@ obj-$(CONFIG_NVME_TARGET_FCLOOP) += nvme-fcloop.o
> obj-$(CONFIG_NVME_TARGET_TCP) += nvmet-tcp.o
>
> nvmet-y += core.o configfs.o admin-cmd.o fabrics-cmd.o \
> - discovery.o io-cmd-file.o io-cmd-bdev.o
> + discovery.o io-cmd-file.o io-cmd-bdev.o pr.o
> nvmet-$(CONFIG_NVME_TARGET_PASSTHRU) += passthru.o
> nvmet-$(CONFIG_BLK_DEV_ZONED) += zns.o
> nvmet-$(CONFIG_NVME_TARGET_AUTH) += fabrics-cmd-auth.o auth.o
> diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
> index 39cb570f833d..791bc7e740c0 100644
> --- a/drivers/nvme/target/admin-cmd.c
> +++ b/drivers/nvme/target/admin-cmd.c
> @@ -176,6 +176,10 @@ static void nvmet_get_cmd_effects_nvm(struct nvme_effects_log *log)
> log->iocs[nvme_cmd_read] =
> log->iocs[nvme_cmd_flush] =
> log->iocs[nvme_cmd_dsm] =
> + log->iocs[nvme_cmd_resv_acquire] =
> + log->iocs[nvme_cmd_resv_register] =
> + log->iocs[nvme_cmd_resv_release] =
> + log->iocs[nvme_cmd_resv_report] =
> cpu_to_le32(NVME_CMD_EFFECTS_CSUPP);
> log->iocs[nvme_cmd_write] =
> log->iocs[nvme_cmd_write_zeroes] =
> @@ -340,6 +344,8 @@ static void nvmet_execute_get_log_page(struct nvmet_req *req)
> return nvmet_execute_get_log_cmd_effects_ns(req);
> case NVME_LOG_ANA:
> return nvmet_execute_get_log_page_ana(req);
> + case NVME_LOG_RESERVATION:
> + return nvmet_execute_get_log_page_resv(req);
> }
> pr_debug("unhandled lid %d on qid %d\n",
> req->cmd->get_log_page.lid, req->sq->qid);
> @@ -550,7 +556,13 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
> */
> id->nmic = NVME_NS_NMIC_SHARED;
> id->anagrpid = cpu_to_le32(req->ns->anagrpid);
> -
> + id->rescap = NVME_PR_SUPPORT_WRITE_EXCLUSIVE |
> + NVME_PR_SUPPORT_EXCLUSIVE_ACCESS |
> + NVME_PR_SUPPORT_WRITE_EXCLUSIVE_REG_ONLY |
> + NVME_PR_SUPPORT_EXCLUSIVE_ACCESS_REG_ONLY |
> + NVME_PR_SUPPORT_WRITE_EXCLUSIVE_ALL_REGS |
> + NVME_PR_SUPPORT_EXCLUSIVE_ACCESS_ALL_REGS |
> + NVME_PR_SUPPORT_IEKEY_VER_1_3_DEF;
> memcpy(&id->nguid, &req->ns->nguid, sizeof(id->nguid));
>
> id->lbaf[0].ds = req->ns->blksize_shift;
> diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
> index d937fe05129e..1ac4802ec818 100644
> --- a/drivers/nvme/target/configfs.c
> +++ b/drivers/nvme/target/configfs.c
> @@ -714,6 +714,32 @@ static ssize_t nvmet_ns_revalidate_size_store(struct config_item *item,
>
> CONFIGFS_ATTR_WO(nvmet_ns_, revalidate_size);
>
> +static ssize_t nvmet_ns_resv_enable_show(struct config_item *item, char *page)
> +{
> + return sprintf(page, "%d\n", to_nvmet_ns(item)->pr.enable);
> +}
> +
> +static ssize_t nvmet_ns_resv_enable_store(struct config_item *item,
> + const char *page, size_t count)
> +{
> + struct nvmet_ns *ns = to_nvmet_ns(item);
> + bool val;
> +
> + if (kstrtobool(page, &val))
> + return -EINVAL;
> +
> + mutex_lock(&ns->subsys->lock);
> + if (ns->enabled) {
> + pr_err("the ns:%d is already enabled.\n", ns->nsid);
> + mutex_unlock(&ns->subsys->lock);
> + return -EINVAL;
> + }
> + ns->pr.enable = val;
> + mutex_unlock(&ns->subsys->lock);
> + return count;
> +}
> +CONFIGFS_ATTR(nvmet_ns_, resv_enable);
> +
> static struct configfs_attribute *nvmet_ns_attrs[] = {
> &nvmet_ns_attr_device_path,
> &nvmet_ns_attr_device_nguid,
> @@ -722,6 +748,7 @@ static struct configfs_attribute *nvmet_ns_attrs[] = {
> &nvmet_ns_attr_enable,
> &nvmet_ns_attr_buffered_io,
> &nvmet_ns_attr_revalidate_size,
> + &nvmet_ns_attr_resv_enable,
> #ifdef CONFIG_PCI_P2PDMA
> &nvmet_ns_attr_p2pmem,
> #endif
> diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
> index 3935165048e7..5bacffc59848 100644
> --- a/drivers/nvme/target/core.c
> +++ b/drivers/nvme/target/core.c
> @@ -591,6 +591,8 @@ int nvmet_ns_enable(struct nvmet_ns *ns)
> if (ns->nsid > subsys->max_nsid)
> subsys->max_nsid = ns->nsid;
>
> + nvmet_pr_init_ns(ns);
> +
> ret = xa_insert(&subsys->namespaces, ns->nsid, ns, GFP_KERNEL);
> if (ret)
> goto out_restore_subsys_maxnsid;
> @@ -651,6 +653,7 @@ void nvmet_ns_disable(struct nvmet_ns *ns)
>
> subsys->nr_namespaces--;
> nvmet_ns_changed(subsys, ns->nsid);
> + nvmet_pr_exit_ns(ns);
> nvmet_ns_dev_disable(ns);
> out_unlock:
> mutex_unlock(&subsys->lock);
> @@ -904,18 +907,34 @@ static u16 nvmet_parse_io_cmd(struct nvmet_req *req)
> return ret;
> }
>
> + if (req->ns->pr.enable) {
> + ret = nvmet_parse_pr_cmd(req);
> + if (!ret)
> + return ret;
> + }
> +
> switch (req->ns->csi) {
> case NVME_CSI_NVM:
> if (req->ns->file)
> - return nvmet_file_parse_io_cmd(req);
> - return nvmet_bdev_parse_io_cmd(req);
> + ret = nvmet_file_parse_io_cmd(req);
> + else
> + ret = nvmet_bdev_parse_io_cmd(req);
> + break;
> case NVME_CSI_ZNS:
> if (IS_ENABLED(CONFIG_BLK_DEV_ZONED))
> - return nvmet_bdev_zns_parse_io_cmd(req);
> - return NVME_SC_INVALID_IO_CMD_SET;
> + ret = nvmet_bdev_zns_parse_io_cmd(req);
> + else
> + ret = NVME_SC_INVALID_IO_CMD_SET;
> + break;
> default:
> - return NVME_SC_INVALID_IO_CMD_SET;
> + ret = NVME_SC_INVALID_IO_CMD_SET;
> }
> + if (ret)
> + return ret;
> +
> + if (req->ns->pr.enable)
> + ret = nvmet_pr_check_cmd_access(req);
> + return ret;
> }
>
> bool nvmet_req_init(struct nvmet_req *req, struct nvmet_cq *cq,
> @@ -1231,6 +1250,21 @@ static void nvmet_init_cap(struct nvmet_ctrl *ctrl)
> nvmet_passthrough_override_cap(ctrl);
> }
>
> +bool nvmet_is_host_still_connected(uuid_t *hostid, struct nvmet_subsys *subsys)
> +{
> + struct nvmet_ctrl *ctrl;
> +
> + mutex_lock(&subsys->lock);
> + list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
> + if (uuid_equal(hostid, &ctrl->hostid)) {
> + mutex_unlock(&subsys->lock);
> + return true;
Perhaps its cleaner to do:
ret = true;
break;
> + }
> + }
> + mutex_unlock(&subsys->lock);
> + return false;
> +}
> +
> struct nvmet_ctrl *nvmet_ctrl_find_get(const char *subsysnqn,
> const char *hostnqn, u16 cntlid,
> struct nvmet_req *req)
> @@ -1450,6 +1484,11 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
> ctrl->err_counter = 0;
> spin_lock_init(&ctrl->error_lock);
>
> + ctrl->pr_log_mgr.counter = 0;
> + ctrl->pr_log_mgr.lost_count = 0;
> + mutex_init(&ctrl->pr_log_mgr.lock);
> + INIT_KFIFO(ctrl->pr_log_mgr.log_queue);
> +
> nvmet_start_keep_alive_timer(ctrl);
>
> mutex_lock(&subsys->lock);
> @@ -1488,6 +1527,7 @@ static void nvmet_ctrl_free(struct kref *ref)
> cancel_work_sync(&ctrl->fatal_err_work);
>
> nvmet_destroy_auth(ctrl);
> + nvmet_ctrl_destroy_pr(ctrl);
>
> ida_free(&cntlid_ida, ctrl->cntlid);
>
> diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
> index 6c8acebe1a1a..b6facb243977 100644
> --- a/drivers/nvme/target/nvmet.h
> +++ b/drivers/nvme/target/nvmet.h
> @@ -20,6 +20,7 @@
> #include <linux/blkdev.h>
> #include <linux/radix-tree.h>
> #include <linux/t10-pi.h>
> +#include <linux/kfifo.h>
>
> #define NVMET_DEFAULT_VS NVME_VS(1, 3, 0)
>
> @@ -30,6 +31,7 @@
> #define NVMET_MN_MAX_SIZE 40
> #define NVMET_SN_MAX_SIZE 20
> #define NVMET_FR_MAX_SIZE 8
> +#define NVMET_PR_LOG_QUEUE_SIZE 64
>
> /*
> * Supported optional AENs:
> @@ -56,6 +58,22 @@
> #define IPO_IATTR_CONNECT_SQE(x) \
> (cpu_to_le32(offsetof(struct nvmf_connect_command, x)))
>
> +struct nvmet_pr_registrant {
> + u64 rkey;
> + uuid_t hostid;
> + enum nvme_pr_type rtype;
> + struct list_head entry;
> + struct rcu_head rcu;
> +};
> +
> +struct nvmet_pr {
> + bool enable;
> + atomic_t generation;
> + struct nvmet_pr_registrant __rcu *holder;
> + struct mutex pr_lock;
> + struct list_head registrant_list;
> +};
> +
> struct nvmet_ns {
> struct percpu_ref ref;
> struct bdev_handle *bdev_handle;
> @@ -85,6 +103,7 @@ struct nvmet_ns {
> int pi_type;
> int metadata_size;
> u8 csi;
> + struct nvmet_pr pr;
> };
>
> static inline struct nvmet_ns *to_nvmet_ns(struct config_item *item)
> @@ -190,6 +209,13 @@ static inline bool nvmet_port_secure_channel_required(struct nvmet_port *port)
> return nvmet_port_disc_addr_treq_secure_channel(port) == NVMF_TREQ_REQUIRED;
> }
>
> +struct nvmet_pr_log_mgr {
> + struct mutex lock;
> + u64 lost_count;
> + u64 counter;
> + DECLARE_KFIFO(log_queue, struct nvme_pr_log, NVMET_PR_LOG_QUEUE_SIZE);
> +};
> +
> struct nvmet_ctrl {
> struct nvmet_subsys *subsys;
> struct nvmet_sq **sqs;
> @@ -243,6 +269,7 @@ struct nvmet_ctrl {
> u8 *dh_key;
> size_t dh_keysize;
> #endif
> + struct nvmet_pr_log_mgr pr_log_mgr;
> };
>
> struct nvmet_subsys {
> @@ -750,4 +777,12 @@ static inline bool nvmet_has_auth(struct nvmet_ctrl *ctrl)
> static inline const char *nvmet_dhchap_dhgroup_name(u8 dhgid) { return NULL; }
> #endif
>
> +void nvmet_pr_init_ns(struct nvmet_ns *ns);
> +u16 nvmet_parse_pr_cmd(struct nvmet_req *req);
> +u16 nvmet_pr_check_cmd_access(struct nvmet_req *req);
> +void nvmet_ctrl_destroy_pr(struct nvmet_ctrl *ctrl);
> +void nvmet_pr_exit_ns(struct nvmet_ns *ns);
> +bool nvmet_is_host_still_connected(uuid_t *hostid, struct nvmet_subsys *subsys);
> +void nvmet_execute_get_log_page_resv(struct nvmet_req *req);
> +
> #endif /* _NVMET_H */
> diff --git a/drivers/nvme/target/pr.c b/drivers/nvme/target/pr.c
> new file mode 100644
> index 000000000000..df71fd23ee47
> --- /dev/null
> +++ b/drivers/nvme/target/pr.c
> @@ -0,0 +1,956 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * NVMe over Fabrics Persist Reservation.
> + * Copyright (c) 2024 Guixin Liu, Alibaba Group.
> + * All rights reserved.
> + */
> +#include "nvmet.h"
> +#include <linux/slab.h>
> +#include <asm/unaligned.h>
> +
> +struct nvmet_pr_register_data {
> + __le64 crkey;
> + __le64 nrkey;
> +};
> +
> +struct nvmet_pr_acquire_data {
> + __le64 crkey;
> + __le64 prkey;
> +};
> +
> +struct nvmet_pr_release_data {
> + __le64 crkey;
> +};
> +
> +static inline struct nvmet_ns *nvmet_pr_to_ns(struct nvmet_pr *pr)
> +{
> + return container_of(pr, struct nvmet_ns, pr);
> +}
> +
> +static u16 nvmet_pr_validate_rtype(u8 rtype)
> +{
> + if (rtype < NVME_PR_WRITE_EXCLUSIVE ||
> + rtype > NVME_PR_EXCLUSIVE_ACCESS_ALL_REGS)
> + return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
> +
> + return NVME_SC_SUCCESS;
> +}
> +
> +static u16 nvmet_pr_set_rtype_and_holder(struct nvmet_pr *pr, u8 rtype,
> + struct nvmet_pr_registrant *reg)
> +{
> + u16 status;
> +
> + status = nvmet_pr_validate_rtype(rtype);
> + if (!status) {
> + reg->rtype = rtype;
> + rcu_assign_pointer(pr->holder, reg);
synchronize_rcu to have rcu grace period elapse?
> + }
> + return status;
> +}
> +
> +static struct nvmet_pr_registrant *
> +nvmet_pr_find_registrant_by_hostid(struct nvmet_pr *pr, uuid_t *hostid)
> +{
> + struct nvmet_pr_registrant *reg;
Perhaps lockdep_assert_held annotation here?
> +
> + list_for_each_entry_rcu(reg, &pr->registrant_list, entry) {
is registrant_list protected by rcu?
> + if (uuid_equal(®->hostid, hostid))
> + return reg;
> + }
> + return NULL;
> +}
> +
> +void nvmet_execute_get_log_page_resv(struct nvmet_req *req)
> +{
> + struct nvmet_pr_log_mgr *log_mgr = &req->sq->ctrl->pr_log_mgr;
> + struct nvme_pr_log next_log = {0};
> + struct nvme_pr_log log = {0};
> + u16 status = NVME_SC_SUCCESS;
> + u64 lost_count;
> + u64 cur_count;
> + u64 next_count;
> +
> + mutex_lock(&log_mgr->lock);
> + if (!kfifo_get(&log_mgr->log_queue, &log))
> + goto out;
> +
> + cur_count = le64_to_cpu(log.count);
> + if (kfifo_peek(&log_mgr->log_queue, &next_log)) {
> + next_count = le64_to_cpu(next_log.count);
> + if (next_count > cur_count)
> + lost_count = next_count - cur_count - 1;
> + else
> + lost_count = U64_MAX - cur_count + next_count - 1;
> + } else {
> + lost_count = log_mgr->lost_count;
> + }
> +
> + log.count = cpu_to_le64(cur_count + lost_count);
> + log_mgr->lost_count -= lost_count;
We need some code comments to say how the count/lost_count are managed
because it looks slightly convoluted here.
> +
> + log.nr_pages = min(kfifo_len(&log_mgr->log_queue) /
> + sizeof(struct nvme_pr_log), 255);
> +
> + status = nvmet_copy_to_sgl(req, 0, &log, sizeof(log));
> +
> +out:
> + mutex_unlock(&log_mgr->lock);
> + nvmet_req_complete(req, status);
> +}
> +
> +static void nvmet_pr_add_resv_log(struct nvmet_ctrl *ctrl, u8 log_type, u32 nsid)
> +{
> + struct nvmet_pr_log_mgr *log_mgr = &ctrl->pr_log_mgr;
> + struct nvme_pr_log log = {0};
> +
> + mutex_lock(&log_mgr->lock);
> + log_mgr->counter++;
> + if (log_mgr->counter == 0)
> + log_mgr->counter = 1;
> +
> + log.count = cpu_to_le64(log_mgr->counter);
> + log.type = log_type;
> + log.nsid = cpu_to_le32(nsid);
> +
> + if (!kfifo_put(&log_mgr->log_queue, log)) {
> + pr_warn("a reservation log lost, cntlid:%d, log_type:%d, nsid:%d\n",
> + ctrl->cntlid, log_type, nsid);
> + log_mgr->lost_count++;
> + }
It'd be good to have a blktest for lost events.
> +
> + mutex_unlock(&log_mgr->lock);
> +}
> +
> +static void nvmet_pr_send_resv_released(struct nvmet_pr *pr, uuid_t *hostid)
> +{
> + struct nvmet_ns *ns = nvmet_pr_to_ns(pr);
> + struct nvmet_subsys *subsys = ns->subsys;
> + struct nvmet_ctrl *ctrl;
> +
> + mutex_lock(&subsys->lock);
> + list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
> + if (!uuid_equal(&ctrl->hostid, hostid) &&
> + nvmet_pr_find_registrant_by_hostid(pr, &ctrl->hostid)) {
> + nvmet_pr_add_resv_log(ctrl,
> + NVME_PR_LOG_RESERVATION_RELEASED, ns->nsid);
> + nvmet_add_async_event(ctrl, NVME_AER_CSS,
> + NVME_AEN_RESV_LOG_PAGE_AVALIABLE,
> + NVME_LOG_RESERVATION);
> + }
> + }
> + mutex_unlock(&subsys->lock);
Wondering if this can consolidate also to nvmet_pr_send_event_by_hostid
but with a filter? Not a must though (don't want to make the interface
too complicated).
> +}
> +
> +static void nvmet_pr_send_event_by_hostid(struct nvmet_pr *pr, uuid_t *hostid,
> + u8 log_type)
> +{
> + struct nvmet_ns *ns = nvmet_pr_to_ns(pr);
> + struct nvmet_subsys *subsys = ns->subsys;
> + struct nvmet_ctrl *ctrl;
> +
> + mutex_lock(&subsys->lock);
> + list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
> + if (uuid_equal(hostid, &ctrl->hostid)) {
> + nvmet_pr_add_resv_log(ctrl, log_type, ns->nsid);
> + nvmet_add_async_event(ctrl, NVME_AER_CSS,
> + NVME_AEN_RESV_LOG_PAGE_AVALIABLE,
> + NVME_LOG_RESERVATION);
> + }
> + }
> + mutex_unlock(&subsys->lock);
> +}
> +
> +static void nvmet_pr_send_resv_preempted(struct nvmet_pr *pr, uuid_t *hostid)
> +{
> + nvmet_pr_send_event_by_hostid(pr, hostid,
> + NVME_PR_LOG_RESERVATOPM_PREEMPTED);
> +}
> +
> +static void nvmet_pr_send_registration_preempted(struct nvmet_pr *pr,
> + uuid_t *hostid)
> +{
> + nvmet_pr_send_event_by_hostid(pr, hostid,
> + NVME_PR_LOG_REGISTRATION_PREEMPTED);
> +}
> +
> +static u16 nvmet_pr_register_check_rkey(struct nvmet_req *req,
> + struct nvmet_pr_register_data *d)
> +{
> + struct nvmet_ctrl *ctrl = req->sq->ctrl;
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *reg;
> +
> + reg = nvmet_pr_find_registrant_by_hostid(pr, &ctrl->hostid);
> + if (!reg || reg->rkey == le64_to_cpu(d->nrkey))
> + return NVME_SC_SUCCESS;
> +
> + return NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> +}
> +
> +static u16 nvmet_pr_register(struct nvmet_req *req,
> + struct nvmet_pr_register_data *d)
> +{
> + struct nvmet_ctrl *ctrl = req->sq->ctrl;
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *reg;
> + u16 status;
> +
> + status = nvmet_pr_register_check_rkey(req, d);
> + if (status)
> + return status;
> +
> + reg = kmalloc(sizeof(*reg), GFP_KERNEL);
> + if (!reg)
> + return NVME_SC_INTERNAL;
> +
> + memset(reg, 0, sizeof(*reg));
> + INIT_LIST_HEAD(®->entry);
> + reg->rkey = le64_to_cpu(d->nrkey);
> + uuid_copy(®->hostid, &ctrl->hostid);
> +
> + mutex_lock(&pr->pr_lock);
> + list_add_tail_rcu(®->entry, &pr->registrant_list);
Can you explain why this is rculist operation?
> + mutex_unlock(&pr->pr_lock);
> + return NVME_SC_SUCCESS;
> +}
> +
> +static void __nvmet_pr_unregister_one(struct nvmet_pr *pr,
> + struct nvmet_pr_registrant *reg)
> +{
> + struct nvmet_pr_registrant *first_reg;
> + struct nvmet_pr_registrant *holder;
> + u8 original_rtype;
> +
> + list_del_rcu(®->entry);
> +
> + holder = rcu_dereference_protected(pr->holder,
> + lockdep_is_held(&pr->pr_lock));
> + if (reg != holder) {
> + kfree_rcu(reg, rcu);
> + return;
goto [out] label instead?
> + }
> +
> + original_rtype = holder->rtype;
> + if (original_rtype == NVME_PR_WRITE_EXCLUSIVE_ALL_REGS ||
> + original_rtype == NVME_PR_EXCLUSIVE_ACCESS_ALL_REGS) {
> + first_reg = list_first_entry_or_null(&pr->registrant_list,
> + struct nvmet_pr_registrant, entry);
> + if (first_reg)
> + first_reg->rtype = original_rtype;
> + rcu_assign_pointer(pr->holder, first_reg);
synchronize_rcu() ?
> + } else {
> + rcu_assign_pointer(pr->holder, NULL);
synchronize_rcu() ?
> +
> + if (original_rtype == NVME_PR_WRITE_EXCLUSIVE_REG_ONLY ||
> + original_rtype == NVME_PR_WRITE_EXCLUSIVE_REG_ONLY)
> + nvmet_pr_send_resv_released(pr, ®->hostid);
> + }
out:
> + kfree_rcu(reg, rcu);
> +}
> +
> +static u16 nvmet_pr_unregister(struct nvmet_req *req,
> + struct nvmet_pr_register_data *d,
> + bool ignore_key)
> +{
> + u16 status = NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> + struct nvmet_ctrl *ctrl = req->sq->ctrl;
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *reg;
> + struct nvmet_pr_registrant *tmp;
> +
> + mutex_lock(&pr->pr_lock);
> + list_for_each_entry_safe(reg, tmp, &pr->registrant_list, entry) {
You are mixing list/rculist traversals, it can't be correct.
> + if (uuid_equal(®->hostid, &ctrl->hostid)) {
> + if (ignore_key || reg->rkey == le64_to_cpu(d->crkey)) {
> + status = NVME_SC_SUCCESS;
> + __nvmet_pr_unregister_one(pr, reg);
> + }
> + break;
> + }
> + }
> + mutex_unlock(&pr->pr_lock);
> +
> + return status;
> +}
> +
> +static u16 __nvmet_pr_do_replace(struct nvmet_pr *pr,
> + struct nvmet_pr_registrant *reg,
> + u64 nrkey)
> +{
> + struct nvmet_pr_registrant *holder;
> + struct nvmet_pr_registrant *new;
> +
> + holder = rcu_dereference_protected(pr->holder,
> + lockdep_is_held(&pr->pr_lock));
> + if (reg != holder) {
> + reg->rkey = nrkey;
> + return NVME_SC_SUCCESS;
> + }
> +
> + new = kmalloc(sizeof(*new), GFP_ATOMIC);
> + if (!new)
> + return NVME_SC_INTERNAL;
> + memcpy(new, reg, sizeof(*new));
> + new->rkey = nrkey;
> + list_del_rcu(®->entry);
> + list_add_rcu(&new->entry, &pr->registrant_list);
> + rcu_assign_pointer(pr->holder, new);
> + kfree_rcu(reg, rcu);
I still think that the correct ordering is:
rcu_assign_pointer(pr->holder, new);
synchronize_rcu();
kfree(reg);
Because what you want is rcu grace period to elapse is after you
(re)assign pr->holder. Then you can safely use a normal kfree for
reg.
> + return NVME_SC_SUCCESS;
> +}
> +
> +static u16 nvmet_pr_replace(struct nvmet_req *req,
> + struct nvmet_pr_register_data *d,
> + bool ignore_key)
> +{
> + u16 status = NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> + struct nvmet_ctrl *ctrl = req->sq->ctrl;
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *reg;
> +
> + mutex_lock(&pr->pr_lock);
> + list_for_each_entry_rcu(reg, &pr->registrant_list, entry) {
> + if (uuid_equal(®->hostid, &ctrl->hostid)) {
> + if (ignore_key || reg->rkey == le64_to_cpu(d->crkey)) {
> + reg->rkey = le64_to_cpu(d->nrkey);
> + status = __nvmet_pr_do_replace(pr, reg,
> + le64_to_cpu(d->nrkey));
So you assign reg->rkey here and then assign it again in _do_replace() ?
I don't understand the logic here.
> + }
> + break;
> + }
> + }
> + mutex_unlock(&pr->pr_lock);
> + return status;
> +}
> +
> +static void nvmet_execute_pr_register(struct nvmet_req *req)
> +{
> + u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
> + bool ignore_key = (bool)((cdw10 >> 3) & 1); /* Ignore existing key, bit 03 */
> + struct nvmet_pr_register_data *d;
> + u8 reg_act = cdw10 & 0x07; /* Reservation Register Action, bit 02:00 */
> + u16 status;
> +
> + d = kmalloc(sizeof(*d), GFP_KERNEL);
> + if (!d) {
> + status = NVME_SC_INTERNAL;
> + goto out;
> + }
> +
> + status = nvmet_copy_from_sgl(req, 0, d, sizeof(*d));
> + if (status)
> + goto free_data;
> +
> + switch (reg_act) {
> + case NVME_PR_REGISTER_ACT_REG:
> + status = nvmet_pr_register(req, d);
> + break;
> + case NVME_PR_REGISTER_ACT_UNREG:
> + status = nvmet_pr_unregister(req, d, ignore_key);
> + break;
> + case NVME_PR_REGISTER_ACT_REPLACE:
> + status = nvmet_pr_replace(req, d, ignore_key);
> + break;
> + default:
> + req->error_loc = offsetof(struct nvme_common_command, cdw10);
> + status = NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
> + break;
> + }
> +free_data:
> + kfree(d);
> +out:
> + if (!status)
> + atomic_inc(&req->ns->pr.generation);
> + nvmet_req_complete(req, status);
> +}
> +
> +static u16 nvmet_pr_acquire(struct nvmet_req *req,
> + struct nvmet_pr_registrant *reg,
> + u8 rtype)
> +{
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *holder;
> +
> + holder = rcu_dereference_protected(pr->holder,
> + lockdep_is_held(&pr->pr_lock));
> + if (holder && reg != holder)
> + return NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> + if (holder && reg == holder) {
> + if (holder->rtype == rtype)
> + return NVME_SC_SUCCESS;
> + return NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> + }
> +
> + return nvmet_pr_set_rtype_and_holder(pr, rtype, reg);
> +}
> +
> +static u16 nvmet_pr_unreg_by_prkey(struct nvmet_pr *pr, u64 prkey,
> + uuid_t *send_hostid)
> +{
> + u16 status = NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> + struct nvmet_pr_registrant *reg;
> + struct nvmet_pr_registrant *tmp;
> +
lockdep_assert_held ?
> + list_for_each_entry_safe(reg, tmp,
> + &pr->registrant_list, entry) {
> + if (reg->rkey == prkey) {
> + status = NVME_SC_SUCCESS;
> + if (!uuid_equal(®->hostid, send_hostid))
> + nvmet_pr_send_registration_preempted(pr,
> + ®->hostid);
> + __nvmet_pr_unregister_one(pr, reg);
> + }
> + }
> + return status;
> +}
> +
> +static u16 nvmet_pr_unreg_by_prkey_except_hostid(struct nvmet_pr *pr, u64 prkey,
> + uuid_t *send_hostid)
> +{
> + u16 status = NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> + struct nvmet_pr_registrant *reg;
> + struct nvmet_pr_registrant *tmp;
> +
lockdep_assert_held ?
> + list_for_each_entry_safe(reg, tmp,
> + &pr->registrant_list, entry) {
> + if (reg->rkey == prkey &&
> + !uuid_equal(®->hostid, send_hostid)) {
> + status = NVME_SC_SUCCESS;
> + nvmet_pr_send_registration_preempted(pr, ®->hostid);
> + __nvmet_pr_unregister_one(pr, reg);
> + }
> + }
> + return status;
> +}
> +
> +static void nvmet_pr_unreg_except_hostid(struct nvmet_pr *pr,
> + uuid_t *send_hostid)
> +{
> + struct nvmet_pr_registrant *reg;
> + struct nvmet_pr_registrant *tmp;
> +
lockdep_assert_held ?
> + list_for_each_entry_safe(reg, tmp,
> + &pr->registrant_list, entry) {
> + if (!uuid_equal(®->hostid, send_hostid)) {
> + nvmet_pr_send_registration_preempted(pr, ®->hostid);
> + __nvmet_pr_unregister_one(pr, reg);
> + }
> + }
> +}
> +
> +static u16 nvmet_pr_create_new_resv(struct nvmet_pr *pr,
> + u8 original_rtype,
> + u8 new_rtype,
> + struct nvmet_pr_registrant *reg)
> +{
> + u16 status;
> +
> + status = nvmet_pr_set_rtype_and_holder(pr, new_rtype, reg);
> + if (!status && original_rtype != new_rtype)
> + nvmet_pr_send_resv_released(pr, ®->hostid);
> + return status;
> +}
> +
> +static u16 nvmet_pr_update_holder_rtype(struct nvmet_pr *pr,
> + struct nvmet_pr_registrant *holder,
> + u8 rtype)
> +{
> + u16 status;
> + struct nvmet_pr_registrant *new;
> +
> + status = nvmet_pr_validate_rtype(rtype);
> + if (status)
> + return status;
> +
> + new = kmalloc(sizeof(*new), GFP_ATOMIC);
> + if (!new)
> + return NVME_SC_INTERNAL;
> +
> + list_del_rcu(&holder->entry);
> + memcpy(new, holder, sizeof(*new));
> + new->rtype = rtype;
> + list_add_tail_rcu(&new->entry, &pr->registrant_list);
> + rcu_assign_pointer(pr->holder, new);
> + kfree_rcu(holder, rcu);
Same comment as before.
> + return NVME_SC_SUCCESS;
> +}
Why do you need this btw? shouldn't this one call
__nvmet_pr_do_replace ?
> +
> +static u16 nvmet_pr_preempt(struct nvmet_req *req,
> + struct nvmet_pr_registrant *reg,
> + u8 rtype,
> + struct nvmet_pr_acquire_data *d)
> +{
> + struct nvmet_ctrl *ctrl = req->sq->ctrl;
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *holder;
> + enum nvme_pr_type original_rtype;
> + u16 status;
> +
> + holder = rcu_dereference_protected(pr->holder,
> + lockdep_is_held(&pr->pr_lock));
> + if (!holder)
> + return nvmet_pr_unreg_by_prkey(pr, le64_to_cpu(d->prkey),
> + &ctrl->hostid);
> +
> + original_rtype = holder->rtype;
> + if (original_rtype == NVME_PR_WRITE_EXCLUSIVE_ALL_REGS ||
> + original_rtype == NVME_PR_EXCLUSIVE_ACCESS_ALL_REGS) {
> + if (!le64_to_cpu(d->prkey)) {
> + nvmet_pr_unreg_except_hostid(pr, &ctrl->hostid);
> + return nvmet_pr_create_new_resv(pr, original_rtype,
> + rtype, reg);
> + }
> + return nvmet_pr_unreg_by_prkey(pr, le64_to_cpu(d->prkey),
> + &ctrl->hostid);
> + }
> +
> + if (holder == reg) {
> + status = nvmet_pr_update_holder_rtype(pr, holder, rtype);
> + if (status)
> + return status;
> + if (original_rtype != rtype)
> + nvmet_pr_send_resv_released(pr, ®->hostid);
> + return status;
> + }
> +
> + if (le64_to_cpu(d->prkey) == holder->rkey) {
> + status = nvmet_pr_unreg_by_prkey_except_hostid(pr,
> + le64_to_cpu(d->prkey), &ctrl->hostid);
> + if (status)
> + return status;
> + return nvmet_pr_create_new_resv(pr, original_rtype, rtype, reg);
> + }
> +
> + if (le64_to_cpu(d->prkey))
> + return nvmet_pr_unreg_by_prkey(pr, le64_to_cpu(d->prkey),
> + &ctrl->hostid);
> + return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
> +}
> +
> +static u16 __nvmet_execute_pr_acquire(struct nvmet_req *req,
> + struct nvmet_pr_registrant *reg,
> + u8 acquire_act,
> + u8 rtype,
> + struct nvmet_pr_acquire_data *d)
> +{
> + u16 status;
> +
> + switch (acquire_act) {
> + case NVME_PR_ACQUIRE_ACT_ACQUIRE:
> + status = nvmet_pr_acquire(req, reg, rtype);
> + goto out;
> + case NVME_PR_ACQUIRE_ACT_PREEMPT:
> + status = nvmet_pr_preempt(req, reg, rtype, d);
> + goto inc_gen;
> + case NVME_PR_ACQUIRE_ACT_PREEMPT_AND_ABORT:
> + status = nvmet_pr_preempt(req, reg, rtype, d);
> + goto inc_gen;
> + default:
> + req->error_loc = offsetof(struct nvme_common_command, cdw10);
> + status = NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
> + goto out;
> + }
> +inc_gen:
> + if (!status)
> + atomic_inc(&req->ns->pr.generation);
> +out:
> + return status;
> +}
> +
> +static void nvmet_execute_pr_acquire(struct nvmet_req *req)
> +{
> + u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
> + bool ignore_key = (bool)((cdw10 >> 3) & 1); /* Ignore existing key, bit 03 */
> + u8 rtype = (u8)((cdw10 >> 8) & 0xff); /* Reservation type, bit 15:08 */
> + u8 acquire_act = cdw10 & 0x07; /* Reservation acquire action, bit 02:00 */
> + struct nvmet_ctrl *ctrl = req->sq->ctrl;
> + struct nvmet_pr_acquire_data *d = NULL;
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *reg;
> + u16 status = NVME_SC_SUCCESS;
> +
> + if (ignore_key) {
> + status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
> + goto out;
> + }
> +
> + d = kmalloc(sizeof(*d), GFP_KERNEL);
> + if (!d) {
> + status = NVME_SC_INTERNAL;
> + goto out;
> + }
> +
> + status = nvmet_copy_from_sgl(req, 0, d, sizeof(*d));
> + if (status)
> + goto free_data;
> +
> + status = NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> + mutex_lock(&pr->pr_lock);
> + list_for_each_entry_rcu(reg, &pr->registrant_list, entry) {
> + if (uuid_equal(®->hostid, &ctrl->hostid) &&
> + reg->rkey == le64_to_cpu(d->crkey)) {
> + status = __nvmet_execute_pr_acquire(req, reg,
> + acquire_act, rtype, d);
> + break;
> + }
> + }
> + mutex_unlock(&pr->pr_lock);
> +
> +free_data:
> + kfree(d);
> +out:
> + nvmet_req_complete(req, status);
> +}
> +
> +static u16 nvmet_pr_release(struct nvmet_req *req,
> + struct nvmet_pr_registrant *reg,
> + u8 rtype)
> +{
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *holder;
> + u8 original_rtype;
> +
> + holder = rcu_dereference_protected(pr->holder,
> + lockdep_is_held(&pr->pr_lock));
> + if (!holder || reg != holder)
> + return NVME_SC_SUCCESS;
> +
> + original_rtype = holder->rtype;
> + if (original_rtype != rtype)
> + return NVME_SC_RESERVATION_CONFLICT | NVME_SC_DNR;
> +
> + rcu_assign_pointer(pr->holder, NULL);
synchronize_rcu ?
> +
> + if (original_rtype != NVME_PR_WRITE_EXCLUSIVE &&
> + original_rtype != NVME_PR_EXCLUSIVE_ACCESS)
> + nvmet_pr_send_resv_released(pr, ®->hostid);
> +
> + return NVME_SC_SUCCESS;
> +}
> +
> +static void nvmet_pr_clear(struct nvmet_req *req)
> +{
> + struct nvmet_pr *pr = &req->ns->pr;
> + struct nvmet_pr_registrant *reg;
> + struct nvmet_pr_registrant *tmp;
> +
lockdep_assert_held ?
> + list_for_each_entry_safe(reg, tmp, &pr->registrant_list, entry) {
> + list_del_rcu(®->entry);
Now registrant_list is an rculist ? I'm not following the logic here.
> + if (!uuid_equal(&req->sq->ctrl->hostid, ®->hostid))
> + nvmet_pr_send_resv_preempted(pr, ®->hostid);
> + kfree_rcu(reg, rcu);
Why are you calling kfree_rcu ?
> + }
> + rcu_assign_pointer(pr->holder, NULL);
synchronize_rcu() ?
> +
> + atomic_inc(&pr->generation);
> +}
...
I'm stopping here, I think you want to either sort out or explain how
you are managing pr, pr->holder, pr->registrant_list etc. It is
difficult for me to follow and make sense of it.
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