[PATCH V4 1/1] nvmet: support reservation feature
Guixin Liu
kanie at linux.alibaba.com
Tue Jan 23 01:45:31 PST 2024
在 2024/1/22 21:03, Sagi Grimberg 写道:
>
>> 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;
>
OK, changed in v5.
>> + }
>> + }
>> + 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?
>
rcu_assign_pointer ensures that all reads after it will see the new value,
we only need to ensure that there are no reads before the old value
free, the
kfree_rcu can make sure that.
>> + }
>> + 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?
>
OK, it will be added in v5.
>> +
>> + list_for_each_entry_rcu(reg, &pr->registrant_list, entry) {
>
> is registrant_list protected by rcu?
Yes.
>
>> + 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.
>
Sure, it will be added in v5.
>> +
>> + 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.
>
I have write a script to test this, but when I use v2.0 nvme-cli to
establish two
connections to a same target with different hostnqn and hostid, the v1.6
nvme-cli
still work, I found that the 07d6b911e in nvme-cli limited this.
And I should close the nvme-multipath also.
>> +
>> + 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).
>
>
Yes, this will make function too complicated, so I didn't do that.
>> +}
>> +
>> +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?
>
I will explain this in bottom.
>> + 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?
>
OK.
>> + }
>> +
>> + 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.
You are right, I should use rculist whether hold the pr_lock or not.
>
>> + 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.
>
The kfree_rcu can achieve the same effect,
Could you plz tell me why should change to like this?
>> + 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.
>
My bad, this is an oversight, it will be changed in v5.
>> + }
>> + 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 ?
OK
>
>> + 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 ?
OK
>
>> + 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 ?
OK
>
>> + 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 ?
>
OK, it will be changed in v5.
>> +
>> +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 ?
OK
>
>> + 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.
>
Yes
>> + 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.
Hi Sagi,
Thank you for the careful review. My bad, I'm not very familiar
with RCU, I wasn't aware
of the many restrictions involved.I will do a deep research on RCU to
see what is correct to do.
I use pr->pr_lock to protect pr->registrant_list and pr->holder
writing, and both of holder
and registrant_list are rcu protected, so they can be read lightly in
nvmet_pr_check_cmd_access.
I was misled by the __dev_exception_clean() into thinking that if I
added a mutex lock, I
wouldn't have to use the rculist marcros anymore, I will change this in
v5, sorry for the trouble...
And I still dont know why we should call synchronize_rcu after
rcu_assign_pointer, if it is for
safely kfree(reg), the kfree_rcu can ensure that. Could you plz expain
that Sagi? Thanks.
Best regards,
Guixin Liu
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