Don't call fabric_drop_tpg from configfs release(), just lower the
refcount, and call fabric_drop_tpg when refcount goes to zero.
We don't need cpu_relax because core_tpg_deregister will only be called
after we know there is no PR use of this tpg (step 4 below):
1) configfs drop_item (target_fabric_drop_tpg) calls config_item_put()
2) if really removed, configfs calls release (target_fabric_tpg_release)
3) tpg_release just calls put_tpg(), so if PR has a ref, the tpg still
isn't freed until PR code drops the ref
4) Last put_tpg(), release_tpg() calls tf_ops.fabric_drop_tpg()
which eventually calls core_tpg_deregister
5) struct contaning tpg freed by fabric after core_tpg_deregister returns
Add a target_core_tpg.h just to stick the get/put_tpg in there.
Signed-off-by: Andy Grover <agrover@xxxxxxxxxx>
---
drivers/target/target_core_fabric_configfs.c | 5 ++---
drivers/target/target_core_pr.c | 16 ++++++----------
drivers/target/target_core_tpg.c | 7 ++++---
drivers/target/target_core_tpg.h | 13 +++++++++++++
include/target/target_core_base.h | 3 +--
5 files changed, 26 insertions(+), 18 deletions(-)
create mode 100644 drivers/target/target_core_tpg.h
diff --git a/drivers/target/target_core_fabric_configfs.c b/drivers/target/target_core_fabric_configfs.c
index fe940d4..45a1763 100644
--- a/drivers/target/target_core_fabric_configfs.c
+++ b/drivers/target/target_core_fabric_configfs.c
@@ -42,6 +42,7 @@
#include "target_core_internal.h"
#include "target_core_alua.h"
#include "target_core_pr.h"
+#include "target_core_tpg.h"
#define TF_CIT_SETUP(_name, _item_ops, _group_ops, _attrs) \
static void target_fabric_setup_##_name##_cit(struct target_fabric_configfs *tf) \
@@ -995,10 +996,8 @@ static void target_fabric_tpg_release(struct config_item *item)
{
struct se_portal_group *se_tpg = container_of(to_config_group(item),
struct se_portal_group, tpg_group);
- struct se_wwn *wwn = se_tpg->se_tpg_wwn;
- struct target_fabric_configfs *tf = wwn->wwn_tf;
- tf->tf_ops.fabric_drop_tpg(se_tpg);
+ put_tpg(se_tpg);
}
static struct configfs_item_operations target_fabric_tpg_base_item_ops = {
diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 0da6696..e2b656b 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -40,6 +40,7 @@
#include "target_core_internal.h"
#include "target_core_pr.h"
#include "target_core_ua.h"
+#include "target_core_tpg.h"
/*
* Used for Specify Initiator Ports Capable Bit (SPEC_I_PT)
@@ -1334,8 +1335,7 @@ static void core_scsi3_tpg_undepend_item(struct se_portal_group *tpg)
configfs_undepend_item(tpg->se_tpg_tfo->tf_subsys,
&tpg->tpg_group.cg_item);
- atomic_dec(&tpg->tpg_pr_ref_count);
- smp_mb__after_atomic_dec();
+ put_tpg(tpg);
}
static int core_scsi3_nodeacl_depend_item(struct se_node_acl *nacl)
@@ -1535,15 +1535,13 @@ core_scsi3_decode_spec_i_port(
if (!i_str)
continue;
- atomic_inc(&tmp_tpg->tpg_pr_ref_count);
- smp_mb__after_atomic_inc();
+ get_tpg(tmp_tpg);
spin_unlock(&dev->se_port_lock);
if (core_scsi3_tpg_depend_item(tmp_tpg)) {
pr_err(" core_scsi3_tpg_depend_item()"
" for tmp_tpg\n");
- atomic_dec(&tmp_tpg->tpg_pr_ref_count);
- smp_mb__after_atomic_dec();
+ put_tpg(tmp_tpg);
ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
goto out_unmap;
}
@@ -3153,15 +3151,13 @@ core_scsi3_emulate_pro_register_and_move(struct se_cmd *cmd, u64 res_key,
if (!dest_tf_ops)
continue;
- atomic_inc(&dest_se_tpg->tpg_pr_ref_count);
- smp_mb__after_atomic_inc();
+ get_tpg(dest_se_tpg);
spin_unlock(&dev->se_port_lock);
if (core_scsi3_tpg_depend_item(dest_se_tpg)) {
pr_err("core_scsi3_tpg_depend_item() failed"
" for dest_se_tpg\n");
- atomic_dec(&dest_se_tpg->tpg_pr_ref_count);
- smp_mb__after_atomic_dec();
+ put_tpg(dest_se_tpg);
ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
goto out_put_pr_reg;
}
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index d9fbdd0..0e30ced 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -38,8 +38,11 @@
#include <target/target_core_base.h>
#include <target/target_core_backend.h>
#include <target/target_core_fabric.h>
+#include <target/target_core_configfs.h>
+
#include "target_core_internal.h"
+#include "target_core_tpg.h"
extern struct se_device *g_lun0_dev;
@@ -637,7 +640,7 @@ int core_tpg_register(
se_tpg->se_tpg_fabric_ptr = tpg_fabric_ptr;
se_tpg->se_tpg_tfo = tfo;
se_tpg->se_tpg_wwn = se_wwn;
- atomic_set(&se_tpg->tpg_pr_ref_count, 0);
+ kref_init(&se_tpg->refcount);
INIT_LIST_HEAD(&se_tpg->acl_node_list);
INIT_LIST_HEAD(&se_tpg->se_tpg_node);
INIT_LIST_HEAD(&se_tpg->tpg_sess_list);
@@ -680,8 +683,6 @@ int core_tpg_deregister(struct se_portal_group *se_tpg)
list_del(&se_tpg->se_tpg_node);
spin_unlock_bh(&tpg_lock);
- while (atomic_read(&se_tpg->tpg_pr_ref_count) != 0)
- cpu_relax();
/*
* Release any remaining demo-mode generated se_node_acl that have
* not been released because of TFO->tpg_check_demo_mode_cache() == 1
diff --git a/drivers/target/target_core_tpg.h b/drivers/target/target_core_tpg.h
new file mode 100644
index 0000000..964d69b
--- /dev/null
+++ b/drivers/target/target_core_tpg.h
@@ -0,0 +1,13 @@
+
+static inline void release_tpg(struct kref *ref)
+{
+ struct se_portal_group *tpg = container_of(ref,
+ struct se_portal_group, refcount);
+ struct se_wwn *wwn = tpg->se_tpg_wwn;
+ struct target_fabric_configfs *tf = wwn->wwn_tf;
+
+ tf->tf_ops.fabric_drop_tpg(tpg);
+}
+
+#define get_tpg(x) kref_get(&x->refcount)
+#define put_tpg(x) kref_put(&x->refcount, release_tpg)
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index e4d5119..dc8bf39 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -781,8 +781,7 @@ struct se_portal_group {
enum transport_tpg_type_table se_tpg_type;
/* Number of ACLed Initiator Nodes for this TPG */
u32 num_node_acls;
- /* Used for PR SPEC_I_PT=1 and REGISTER_AND_MOVE */
- atomic_t tpg_pr_ref_count;
+ struct kref refcount;
/* Spinlock for adding/removing ACLed Nodes */
spinlock_t acl_node_lock;
/* Spinlock for adding/removing sessions */
--
1.7.1
--
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