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scsi: target: Move sess cmd counter to new struct 

[ Upstream commit becd9be606 ]

iSCSI needs to wait on outstanding commands like how SRP and the FC/FCoE
drivers do. It can't use target_stop_session() because for MCS support we
can't stop the entire session during recovery because if other connections
are OK then we want to be able to continue to execute I/O on them.

Move the per session cmd counters to a new struct so iSCSI can allocate
them per connection. The xcopy code can also just not allocate in the
future since it doesn't need to track commands.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20230319015620.96006-2-michael.christie@oracle.com
Reviewed-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Stable-dep-of: 395cee83d0 ("scsi: target: iscsit: Stop/wait on cmds during conn close")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Mike Christie 2023-03-18 20:56:12 -05:00 committed by Greg Kroah-Hartman
parent 87ee7227cc
commit 76b77646f1
4 changed files with 107 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/target/target_core_tpg.c
View File

@ -328,7 +328,7 @@ static void target_shutdown_sessions(struct se_node_acl *acl)
restart:
spin_lock_irqsave(&acl->nacl_sess_lock, flags);
list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
if (atomic_read(&sess->stopped))
if (sess->cmd_cnt && atomic_read(&sess->cmd_cnt->stopped))
continue;
list_del_init(&sess->sess_acl_list);

135
drivers/target/target_core_transport.c
View File

@ -220,11 +220,49 @@ void transport_subsystem_check_init(void)
sub_api_initialized = 1;
}
static void target_release_sess_cmd_refcnt(struct percpu_ref *ref)
static void target_release_cmd_refcnt(struct percpu_ref *ref)
{
struct se_session *sess = container_of(ref, typeof(*sess), cmd_count);
struct target_cmd_counter *cmd_cnt = container_of(ref,
typeof(*cmd_cnt),
refcnt);
wake_up(&cmd_cnt->refcnt_wq);
}
wake_up(&sess->cmd_count_wq);
static struct target_cmd_counter *target_alloc_cmd_counter(void)
{
struct target_cmd_counter *cmd_cnt;
int rc;
cmd_cnt = kzalloc(sizeof(*cmd_cnt), GFP_KERNEL);
if (!cmd_cnt)
return NULL;
init_completion(&cmd_cnt->stop_done);
init_waitqueue_head(&cmd_cnt->refcnt_wq);
atomic_set(&cmd_cnt->stopped, 0);
rc = percpu_ref_init(&cmd_cnt->refcnt, target_release_cmd_refcnt, 0,
GFP_KERNEL);
if (rc)
goto free_cmd_cnt;
return cmd_cnt;
free_cmd_cnt:
kfree(cmd_cnt);
return NULL;
}
static void target_free_cmd_counter(struct target_cmd_counter *cmd_cnt)
{
/*
* Drivers like loop do not call target_stop_session during session
* shutdown so we have to drop the ref taken at init time here.
*/
if (!atomic_read(&cmd_cnt->stopped))
percpu_ref_put(&cmd_cnt->refcnt);
percpu_ref_exit(&cmd_cnt->refcnt);
}
/**
@ -238,25 +276,17 @@ int transport_init_session(struct se_session *se_sess)
INIT_LIST_HEAD(&se_sess->sess_list);
INIT_LIST_HEAD(&se_sess->sess_acl_list);
spin_lock_init(&se_sess->sess_cmd_lock);
init_waitqueue_head(&se_sess->cmd_count_wq);
init_completion(&se_sess->stop_done);
atomic_set(&se_sess->stopped, 0);
return percpu_ref_init(&se_sess->cmd_count,
target_release_sess_cmd_refcnt, 0, GFP_KERNEL);
se_sess->cmd_cnt = target_alloc_cmd_counter();
if (!se_sess->cmd_cnt)
return -ENOMEM;
return 0;
}
EXPORT_SYMBOL(transport_init_session);
void transport_uninit_session(struct se_session *se_sess)
{
/*
* Drivers like iscsi and loop do not call target_stop_session
* during session shutdown so we have to drop the ref taken at init
* time here.
*/
if (!atomic_read(&se_sess->stopped))
percpu_ref_put(&se_sess->cmd_count);
percpu_ref_exit(&se_sess->cmd_count);
target_free_cmd_counter(se_sess->cmd_cnt);
}
/**
@ -2970,9 +3000,16 @@ int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
se_cmd->se_cmd_flags |= SCF_ACK_KREF;
}
if (!percpu_ref_tryget_live(&se_sess->cmd_count))
ret = -ESHUTDOWN;
/*
* Users like xcopy do not use counters since they never do a stop
* and wait.
*/
if (se_sess->cmd_cnt) {
if (!percpu_ref_tryget_live(&se_sess->cmd_cnt->refcnt))
ret = -ESHUTDOWN;
else
se_cmd->cmd_cnt = se_sess->cmd_cnt;
}
if (ret && ack_kref)
target_put_sess_cmd(se_cmd);
@ -2993,7 +3030,7 @@ static void target_free_cmd_mem(struct se_cmd *cmd)
static void target_release_cmd_kref(struct kref *kref)
{
struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
struct se_session *se_sess = se_cmd->se_sess;
struct target_cmd_counter *cmd_cnt = se_cmd->cmd_cnt;
struct completion *free_compl = se_cmd->free_compl;
struct completion *abrt_compl = se_cmd->abrt_compl;
@ -3004,7 +3041,8 @@ static void target_release_cmd_kref(struct kref *kref)
if (abrt_compl)
complete(abrt_compl);
percpu_ref_put(&se_sess->cmd_count);
if (cmd_cnt)
percpu_ref_put(&cmd_cnt->refcnt);
}
/**
@ -3123,46 +3161,65 @@ void target_show_cmd(const char *pfx, struct se_cmd *cmd)
}
EXPORT_SYMBOL(target_show_cmd);
static void target_stop_session_confirm(struct percpu_ref *ref)
static void target_stop_cmd_counter_confirm(struct percpu_ref *ref)
{
struct se_session *se_sess = container_of(ref, struct se_session,
cmd_count);
complete_all(&se_sess->stop_done);
struct target_cmd_counter *cmd_cnt = container_of(ref,
struct target_cmd_counter,
refcnt);
complete_all(&cmd_cnt->stop_done);
}
/**
* target_stop_cmd_counter - Stop new IO from being added to the counter.
* @cmd_cnt: counter to stop
*/
static void target_stop_cmd_counter(struct target_cmd_counter *cmd_cnt)
{
pr_debug("Stopping command counter.\n");
if (!atomic_cmpxchg(&cmd_cnt->stopped, 0, 1))
percpu_ref_kill_and_confirm(&cmd_cnt->refcnt,
target_stop_cmd_counter_confirm);
}
/**
* target_stop_session - Stop new IO from being queued on the session.
* @se_sess: session to stop
* @se_sess: session to stop
*/
void target_stop_session(struct se_session *se_sess)
{
pr_debug("Stopping session queue.\n");
if (atomic_cmpxchg(&se_sess->stopped, 0, 1) == 0)
percpu_ref_kill_and_confirm(&se_sess->cmd_count,
target_stop_session_confirm);
target_stop_cmd_counter(se_sess->cmd_cnt);
}
EXPORT_SYMBOL(target_stop_session);
/**
* target_wait_for_sess_cmds - Wait for outstanding commands
* @se_sess: session to wait for active I/O
* target_wait_for_cmds - Wait for outstanding cmds.
* @cmd_cnt: counter to wait for active I/O for.
*/
void target_wait_for_sess_cmds(struct se_session *se_sess)
static void target_wait_for_cmds(struct target_cmd_counter *cmd_cnt)
{
int ret;
WARN_ON_ONCE(!atomic_read(&se_sess->stopped));
WARN_ON_ONCE(!atomic_read(&cmd_cnt->stopped));
do {
pr_debug("Waiting for running cmds to complete.\n");
ret = wait_event_timeout(se_sess->cmd_count_wq,
percpu_ref_is_zero(&se_sess->cmd_count),
180 * HZ);
ret = wait_event_timeout(cmd_cnt->refcnt_wq,
percpu_ref_is_zero(&cmd_cnt->refcnt),
180 * HZ);
} while (ret <= 0);
wait_for_completion(&se_sess->stop_done);
wait_for_completion(&cmd_cnt->stop_done);
pr_debug("Waiting for cmds done.\n");
}
/**
* target_wait_for_sess_cmds - Wait for outstanding commands
* @se_sess: session to wait for active I/O
*/
void target_wait_for_sess_cmds(struct se_session *se_sess)
{
target_wait_for_cmds(se_sess->cmd_cnt);
}
EXPORT_SYMBOL(target_wait_for_sess_cmds);
/*

1
include/target/iscsi/iscsi_target_core.h
View File

@ -600,6 +600,7 @@ struct iscsit_conn {
struct iscsi_tpg_np *tpg_np;
/* Pointer to parent session */
struct iscsit_session *sess;
struct target_cmd_counter *cmd_cnt;
int bitmap_id;
int rx_thread_active;
struct task_struct *rx_thread;

13
include/target/target_core_base.h
View File

@ -492,6 +492,7 @@ struct se_cmd {
struct se_lun *se_lun;
/* Only used for internal passthrough and legacy TCM fabric modules */
struct se_session *se_sess;
struct target_cmd_counter *cmd_cnt;
struct se_tmr_req *se_tmr_req;
struct llist_node se_cmd_list;
struct completion *free_compl;
@ -617,22 +618,26 @@ static inline struct se_node_acl *fabric_stat_to_nacl(struct config_item *item)
acl_fabric_stat_group);
}
struct se_session {
struct target_cmd_counter {
struct percpu_ref refcnt;
wait_queue_head_t refcnt_wq;
struct completion stop_done;
atomic_t stopped;
};
struct se_session {
u64 sess_bin_isid;
enum target_prot_op sup_prot_ops;
enum target_prot_type sess_prot_type;
struct se_node_acl *se_node_acl;
struct se_portal_group *se_tpg;
void *fabric_sess_ptr;
struct percpu_ref cmd_count;
struct list_head sess_list;
struct list_head sess_acl_list;
spinlock_t sess_cmd_lock;
wait_queue_head_t cmd_count_wq;
struct completion stop_done;
void *sess_cmd_map;
struct sbitmap_queue sess_tag_pool;
struct target_cmd_counter *cmd_cnt;
};
struct se_device;