Merge patch series "target: TMF and recovery fixes"

Mike Christie <michael.christie@oracle.com> says:

The following patches apply over Martin's 6.4 branches and Linus's tree.
They fix a couple regressions in iscsit that occur when there are TMRs
executing and a connection is closed. It also includes Dimitry's fixes in
related code paths for cmd cleanup when ERL2 is used and the write pending
hang during conn cleanup.

This version of the patchset brings it back to just regressions and fixes
for bugs we have a lot of users hitting. I'm going to fix isert and get it
hooked into iscsit properly in a second patchset, because this one was
getting so large. I've also moved my cleanup type of patches for a 3rd
patchset.

Link: https://lore.kernel.org/r/20230319015620.96006-1-michael.christie@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 128 insertions, 71 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 5926316252eb..86adff2a86ed 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -220,12 +220,52 @@ 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);
+}
+
+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);
 
-	wake_up(&sess->cmd_count_wq);
+	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;
 }
+EXPORT_SYMBOL_GPL(target_alloc_cmd_counter);
+
+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);
+}
+EXPORT_SYMBOL_GPL(target_free_cmd_counter);
 
 /**
  * transport_init_session - initialize a session object
@@ -233,32 +273,14 @@ static void target_release_sess_cmd_refcnt(struct percpu_ref *ref)
  *
  * The caller must have zero-initialized @se_sess before calling this function.
  */
-int transport_init_session(struct se_session *se_sess)
+void 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);
 }
 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);
-}
-
 /**
  * transport_alloc_session - allocate a session object and initialize it
  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
@@ -266,7 +288,6 @@ void transport_uninit_session(struct se_session *se_sess)
 struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
 {
 	struct se_session *se_sess;
-	int ret;
 
 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
 	if (!se_sess) {
@@ -274,11 +295,7 @@ struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
 				" se_sess_cache\n");
 		return ERR_PTR(-ENOMEM);
 	}
-	ret = transport_init_session(se_sess);
-	if (ret < 0) {
-		kmem_cache_free(se_sess_cache, se_sess);
-		return ERR_PTR(ret);
-	}
+	transport_init_session(se_sess);
 	se_sess->sup_prot_ops = sup_prot_ops;
 
 	return se_sess;
@@ -444,8 +461,13 @@ target_setup_session(struct se_portal_group *tpg,
 		     int (*callback)(struct se_portal_group *,
 				     struct se_session *, void *))
 {
+	struct target_cmd_counter *cmd_cnt;
 	struct se_session *sess;
+	int rc;
 
+	cmd_cnt = target_alloc_cmd_counter();
+	if (!cmd_cnt)
+		return ERR_PTR(-ENOMEM);
 	/*
 	 * If the fabric driver is using percpu-ida based pre allocation
 	 * of I/O descriptor tags, go ahead and perform that setup now..
@@ -455,29 +477,36 @@ target_setup_session(struct se_portal_group *tpg,
 	else
 		sess = transport_alloc_session(prot_op);
 
-	if (IS_ERR(sess))
-		return sess;
+	if (IS_ERR(sess)) {
+		rc = PTR_ERR(sess);
+		goto free_cnt;
+	}
+	sess->cmd_cnt = cmd_cnt;
 
 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
 					(unsigned char *)initiatorname);
 	if (!sess->se_node_acl) {
-		transport_free_session(sess);
-		return ERR_PTR(-EACCES);
+		rc = -EACCES;
+		goto free_sess;
 	}
 	/*
 	 * Go ahead and perform any remaining fabric setup that is
 	 * required before transport_register_session().
 	 */
 	if (callback != NULL) {
-		int rc = callback(tpg, sess, private);
-		if (rc) {
-			transport_free_session(sess);
-			return ERR_PTR(rc);
-		}
+		rc = callback(tpg, sess, private);
+		if (rc)
+			goto free_sess;
 	}
 
 	transport_register_session(tpg, sess->se_node_acl, sess, private);
 	return sess;
+
+free_sess:
+	transport_free_session(sess);
+free_cnt:
+	target_free_cmd_counter(cmd_cnt);
+	return ERR_PTR(rc);
 }
 EXPORT_SYMBOL(target_setup_session);
 
@@ -602,7 +631,8 @@ void transport_free_session(struct se_session *se_sess)
 		sbitmap_queue_free(&se_sess->sess_tag_pool);
 		kvfree(se_sess->sess_cmd_map);
 	}
-	transport_uninit_session(se_sess);
+	if (se_sess->cmd_cnt)
+		target_free_cmd_counter(se_sess->cmd_cnt);
 	kmem_cache_free(se_sess_cache, se_sess);
 }
 EXPORT_SYMBOL(transport_free_session);
@@ -1412,14 +1442,12 @@ target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
  *
  * Preserves the value of @cmd->tag.
  */
-void __target_init_cmd(
-	struct se_cmd *cmd,
-	const struct target_core_fabric_ops *tfo,
-	struct se_session *se_sess,
-	u32 data_length,
-	int data_direction,
-	int task_attr,
-	unsigned char *sense_buffer, u64 unpacked_lun)
+void __target_init_cmd(struct se_cmd *cmd,
+		       const struct target_core_fabric_ops *tfo,
+		       struct se_session *se_sess, u32 data_length,
+		       int data_direction, int task_attr,
+		       unsigned char *sense_buffer, u64 unpacked_lun,
+		       struct target_cmd_counter *cmd_cnt)
 {
 	INIT_LIST_HEAD(&cmd->se_delayed_node);
 	INIT_LIST_HEAD(&cmd->se_qf_node);
@@ -1439,6 +1467,7 @@ void __target_init_cmd(
 	cmd->sam_task_attr = task_attr;
 	cmd->sense_buffer = sense_buffer;
 	cmd->orig_fe_lun = unpacked_lun;
+	cmd->cmd_cnt = cmd_cnt;
 
 	if (!(cmd->se_cmd_flags & SCF_USE_CPUID))
 		cmd->cpuid = raw_smp_processor_id();
@@ -1658,7 +1687,8 @@ int target_init_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
 	 * target_core_fabric_ops->queue_status() callback
 	 */
 	__target_init_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, data_length,
-			  data_dir, task_attr, sense, unpacked_lun);
+			  data_dir, task_attr, sense, unpacked_lun,
+			  se_sess->cmd_cnt);
 
 	/*
 	 * Obtain struct se_cmd->cmd_kref reference. A second kref_get here is
@@ -1953,7 +1983,8 @@ int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
 	BUG_ON(!se_tpg);
 
 	__target_init_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
-			  0, DMA_NONE, TCM_SIMPLE_TAG, sense, unpacked_lun);
+			  0, DMA_NONE, TCM_SIMPLE_TAG, sense, unpacked_lun,
+			  se_sess->cmd_cnt);
 	/*
 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
 	 * allocation failure.
@@ -2957,7 +2988,6 @@ EXPORT_SYMBOL(transport_generic_free_cmd);
  */
 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
 {
-	struct se_session *se_sess = se_cmd->se_sess;
 	int ret = 0;
 
 	/*
@@ -2970,9 +3000,14 @@ 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_cmd->cmd_cnt) {
+		if (!percpu_ref_tryget_live(&se_cmd->cmd_cnt->refcnt))
+			ret = -ESHUTDOWN;
+	}
 	if (ret && ack_kref)
 		target_put_sess_cmd(se_cmd);
 
@@ -2993,7 +3028,7 @@ 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 +3039,8 @@ 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 +3159,67 @@ 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 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
+ */
+void target_stop_cmd_counter(struct target_cmd_counter *cmd_cnt)
 {
-	struct se_session *se_sess = container_of(ref, struct se_session,
-						  cmd_count);
-	complete_all(&se_sess->stop_done);
+	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);
 }
+EXPORT_SYMBOL_GPL(target_stop_cmd_counter);
 
 /**
  * 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)
+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");
 }
+EXPORT_SYMBOL_GPL(target_wait_for_cmds);
+
+/**
+ * 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);
 
 /*