Move the subsystem registration and lookup into target_core_hba.c, and
make the list of subsystems local to the file. Get rid of the sub_api_hba_cnt
field and instead to proper reference counting of the module inside the
subsystem_mutex to make it non-racy vs module removal.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: lio-core/drivers/target/target_core_hba.c
===================================================================
--- lio-core.orig/drivers/target/target_core_hba.c 2010-11-23 22:36:42.000000000 +0100
+++ lio-core/drivers/target/target_core_hba.c 2010-11-23 22:43:18.977254087 +0100
@@ -44,10 +43,63 @@
#include "target_core_hba.h"
+static LIST_HEAD(subsystem_list);
+static DEFINE_MUTEX(subsystem_mutex);
+
+int transport_subsystem_register(struct se_subsystem_api *sub_api)
+{
+ struct se_subsystem_api *s;
+
+ INIT_LIST_HEAD(&sub_api->sub_api_list);
+
+ mutex_lock(&subsystem_mutex);
+ list_for_each_entry(s, &subsystem_list, sub_api_list) {
+ if (!(strcmp(s->name, sub_api->name))) {
+ printk(KERN_ERR "%p is already registered with"
+ " duplicate name %s, unable to process"
+ " request\n", s, s->name);
+ mutex_unlock(&subsystem_mutex);
+ return -EEXIST;
+ }
+ }
+ list_add_tail(&sub_api->sub_api_list, &subsystem_list);
+ mutex_unlock(&subsystem_mutex);
+
+ printk(KERN_INFO "TCM: Registered subsystem plugin: %s struct module:"
+ " %p\n", sub_api->name, sub_api->owner);
+ return 0;
+}
+EXPORT_SYMBOL(transport_subsystem_register);
+
+void transport_subsystem_release(struct se_subsystem_api *sub_api)
+{
+ mutex_lock(&subsystem_mutex);
+ list_del(&sub_api->sub_api_list);
+ mutex_unlock(&subsystem_mutex);
+}
+EXPORT_SYMBOL(transport_subsystem_release);
+
+static struct se_subsystem_api *core_get_backend(const char *sub_name)
+{
+ struct se_subsystem_api *s;
+
+ mutex_lock(&subsystem_mutex);
+ list_for_each_entry(s, &subsystem_list, sub_api_list) {
+ if (!strcmp(s->name, sub_name))
+ goto found;
+ }
+ mutex_unlock(&subsystem_mutex);
+ return NULL;
+found:
+ if (s->owner && !try_module_get(s->owner))
+ s = NULL;
+ mutex_unlock(&subsystem_mutex);
+ return s;
+}
+
struct se_hba *
core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
{
- struct se_subsystem_api *t;
struct se_hba *hba;
int ret = 0;
@@ -68,30 +120,13 @@ core_alloc_hba(const char *plugin_name,
atomic_set(&hba->max_queue_depth, 0);
atomic_set(&hba->left_queue_depth, 0);
- t = transport_core_get_sub_by_name(plugin_name);
- if (!t) {
+ hba->transport = core_get_backend(plugin_name);
+ if (!hba->transport) {
ret = -EINVAL;
goto out_free_hba;
}
- hba->transport = t;
-
- /*
- * Get TCM subsystem api struct module reference to struct se_hba
- */
- if (t->owner) {
- /*
- * Grab a struct module reference count for subsystem plugin
- */
- if (!try_module_get(t->owner)) {
- printk(KERN_ERR "try_module_get() failed for %s\n",
- t->owner->name);
- ret = -EINVAL;
- goto out_put_subsystem;
- }
- }
-
- ret = t->attach_hba(hba, plugin_dep_id);
+ ret = hba->transport->attach_hba(hba, plugin_dep_id);
if (ret < 0)
goto out_module_put;
@@ -106,11 +141,9 @@ core_alloc_hba(const char *plugin_name,
return hba;
out_module_put:
- if (t->owner)
- module_put(t->owner);
-out_put_subsystem:
+ if (hba->transport->owner)
+ module_put(hba->transport->owner);
hba->transport = NULL;
- transport_core_put_sub(t);
out_free_hba:
kfree(hba);
return ERR_PTR(ret);
@@ -134,11 +167,6 @@ core_delete_hba(struct se_hba *hba)
spin_unlock(&hba->device_lock);
hba->transport->detach_hba(hba);
- if (hba->transport->owner)
- module_put(hba->transport->owner);
-
- if (!(hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
- transport_core_put_sub(hba->transport);
spin_lock(&se_global->hba_lock);
list_del(&hba->hba_list);
@@ -149,6 +177,8 @@ core_delete_hba(struct se_hba *hba)
printk(KERN_INFO "CORE_HBA[%d] - Detached HBA from Generic Target"
" Core\n", hba->hba_id);
+ if (hba->transport->owner)
+ module_put(hba->transport->owner);
kfree(hba);
return 0;
}
Index: lio-core/drivers/target/target_core_transport.c
===================================================================
--- lio-core.orig/drivers/target/target_core_transport.c 2010-11-23 22:34:07.000000000 +0100
+++ lio-core/drivers/target/target_core_transport.c 2010-11-23 22:37:25.121253389 +0100
@@ -289,13 +289,11 @@ int init_se_global(void)
INIT_LIST_HEAD(&global->g_se_tpg_list);
INIT_LIST_HEAD(&global->g_hba_list);
INIT_LIST_HEAD(&global->g_se_dev_list);
- INIT_LIST_HEAD(&global->g_sub_api_list);
spin_lock_init(&global->g_device_lock);
spin_lock_init(&global->hba_lock);
spin_lock_init(&global->se_tpg_lock);
spin_lock_init(&global->lu_gps_lock);
spin_lock_init(&global->plugin_class_lock);
- mutex_init(&global->g_sub_api_mutex);
se_cmd_cache = kmem_cache_create("se_cmd_cache",
sizeof(struct se_cmd), __alignof__(struct se_cmd), 0, NULL);
@@ -472,64 +470,6 @@ int transport_subsystem_check_init(void)
return 0;
}
-int transport_subsystem_register(
- struct se_subsystem_api *sub_api)
-{
- struct se_subsystem_api *s;
-
- INIT_LIST_HEAD(&sub_api->sub_api_list);
-
- mutex_lock(&se_global->g_sub_api_mutex);
- list_for_each_entry(s, &se_global->g_sub_api_list, sub_api_list) {
- if (!(strcmp(s->name, sub_api->name))) {
- printk(KERN_ERR "%p is already registered with"
- " duplicate name %s, unable to process"
- " request\n", s, s->name);
- mutex_unlock(&se_global->g_sub_api_mutex);
- return -EEXIST;
- }
- }
- list_add_tail(&sub_api->sub_api_list, &se_global->g_sub_api_list);
- mutex_unlock(&se_global->g_sub_api_mutex);
-
- printk(KERN_INFO "TCM: Registered subsystem plugin: %s struct module:"
- " %p\n", sub_api->name, sub_api->owner);
- return 0;
-}
-EXPORT_SYMBOL(transport_subsystem_register);
-
-void transport_subsystem_release(struct se_subsystem_api *sub_api)
-{
- mutex_lock(&se_global->g_sub_api_mutex);
- list_del(&sub_api->sub_api_list);
- mutex_unlock(&se_global->g_sub_api_mutex);
-}
-EXPORT_SYMBOL(transport_subsystem_release);
-
-struct se_subsystem_api *transport_core_get_sub_by_name(const char *sub_name)
-{
- struct se_subsystem_api *s;
-
- mutex_lock(&se_global->g_sub_api_mutex);
- list_for_each_entry(s, &se_global->g_sub_api_list, sub_api_list) {
- if (!(strcmp(s->name, sub_name))) {
- atomic_inc(&s->sub_api_hba_cnt);
- smp_mb__after_atomic_inc();
- mutex_unlock(&se_global->g_sub_api_mutex);
- return s;
- }
- }
- mutex_unlock(&se_global->g_sub_api_mutex);
-
- return NULL;
-}
-
-void transport_core_put_sub(struct se_subsystem_api *s)
-{
- atomic_dec(&s->sub_api_hba_cnt);
- smp_mb__after_atomic_dec();
-}
-
struct se_session *transport_init_session(void)
{
struct se_session *se_sess;
Index: lio-core/include/target/target_core_base.h
===================================================================
--- lio-core.orig/include/target/target_core_base.h 2010-11-23 22:34:08.000000000 +0100
+++ lio-core/include/target/target_core_base.h 2010-11-23 22:37:20.333253110 +0100
@@ -983,12 +983,10 @@ struct se_global {
struct list_head g_se_tpg_list;
struct list_head g_hba_list;
struct list_head g_se_dev_list;
- struct list_head g_sub_api_list;
struct se_hba *g_lun0_hba;
struct se_subsystem_dev *g_lun0_su_dev;
struct se_device *g_lun0_dev;
struct t10_alua_lu_gp *default_lu_gp;
- struct mutex g_sub_api_mutex;
spinlock_t g_device_lock;
spinlock_t hba_lock;
spinlock_t se_tpg_lock;
Index: lio-core/include/target/target_core_transport.h
===================================================================
--- lio-core.orig/include/target/target_core_transport.h 2010-11-23 22:34:08.000000000 +0100
+++ lio-core/include/target/target_core_transport.h 2010-11-23 22:38:54.534253179 +0100
@@ -130,8 +130,6 @@ extern int transport_subsystem_check_ini
extern int transport_subsystem_register(struct se_subsystem_api *);
extern void transport_subsystem_release(struct se_subsystem_api *);
extern void transport_load_plugins(void);
-extern struct se_subsystem_api *transport_core_get_sub_by_name(const char *);
-extern void transport_core_put_sub(struct se_subsystem_api *);
extern struct se_session *transport_init_session(void);
extern void __transport_register_session(struct se_portal_group *,
struct se_node_acl *,
@@ -238,10 +236,6 @@ struct se_subsystem_api {
*/
struct module *owner;
/*
- * Counter for struct se_hba reference
- */
- atomic_t sub_api_hba_cnt;
- /*
* Used for global se_subsystem_api list_head
*/
struct list_head sub_api_list;
--
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