From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch converts core_[enable,disable]_device_list_for_node() to RCU
updater path code when modifying se_dev_entry pointers.
It includes protected rcu_assign_pointer() and invokes synchronize_rcu()
to wait for RCU read paths to finish.
Required for subsequent conversion to se_deve->pr_ref percpu-refcount.
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_device.c | 50 ++++++++++++++++---------------------
1 file changed, 22 insertions(+), 28 deletions(-)
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index be893c8..9385e16 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -324,31 +324,16 @@ int core_enable_device_list_for_node(
struct se_port *port = lun->lun_sep;
struct se_dev_entry *deve;
- spin_lock_irq(&nacl->device_list_lock);
-
- deve = nacl->device_list[mapped_lun];
-
/*
* Check if the call is handling demo mode -> explicit LUN ACL
* transition. This transition must be for the same struct se_lun
* + mapped_lun that was setup in demo mode..
*/
+ spin_lock_irq(&nacl->lun_entry_lock);
+ deve = nacl->lun_entry_hlist[mapped_lun];
if (deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS) {
- if (deve->se_lun_acl != NULL) {
- pr_err("struct se_dev_entry->se_lun_acl"
- " already set for demo mode -> explicit"
- " LUN ACL transition\n");
- spin_unlock_irq(&nacl->device_list_lock);
- return -EINVAL;
- }
- if (deve->se_lun != lun) {
- pr_err("struct se_dev_entry->se_lun does"
- " match passed struct se_lun for demo mode"
- " -> explicit LUN ACL transition\n");
- spin_unlock_irq(&nacl->device_list_lock);
- return -EINVAL;
- }
- deve->se_lun_acl = lun_acl;
+ BUG_ON(deve->se_lun_acl != NULL);
+ BUG_ON(deve->se_lun != lun);
if (lun_access & TRANSPORT_LUNFLAGS_READ_WRITE) {
deve->lun_flags &= ~TRANSPORT_LUNFLAGS_READ_ONLY;
@@ -357,13 +342,13 @@ int core_enable_device_list_for_node(
deve->lun_flags &= ~TRANSPORT_LUNFLAGS_READ_WRITE;
deve->lun_flags |= TRANSPORT_LUNFLAGS_READ_ONLY;
}
+ rcu_assign_pointer(deve->se_lun_acl, lun_acl);
+ spin_unlock_irq(&nacl->lun_entry_lock);
- spin_unlock_irq(&nacl->device_list_lock);
+ synchronize_rcu();
return 0;
}
- deve->se_lun = lun;
- deve->se_lun_acl = lun_acl;
deve->mapped_lun = mapped_lun;
deve->lun_flags |= TRANSPORT_LUNFLAGS_INITIATOR_ACCESS;
@@ -377,12 +362,16 @@ int core_enable_device_list_for_node(
deve->creation_time = get_jiffies_64();
deve->attach_count++;
- spin_unlock_irq(&nacl->device_list_lock);
+
+ rcu_assign_pointer(deve->se_lun, lun);
+ rcu_assign_pointer(deve->se_lun_acl, lun_acl);
+ spin_unlock_irq(&nacl->lun_entry_lock);
spin_lock_bh(&port->sep_alua_lock);
list_add_tail(&deve->alua_port_list, &port->sep_alua_list);
spin_unlock_bh(&port->sep_alua_lock);
+ synchronize_rcu();
return 0;
}
@@ -399,8 +388,10 @@ int core_disable_device_list_for_node(
struct se_portal_group *tpg)
{
struct se_port *port = lun->lun_sep;
- struct se_dev_entry *deve = nacl->device_list[mapped_lun];
+ struct se_dev_entry *deve;
+ rcu_read_lock();
+ deve = rcu_dereference(nacl->lun_entry_hlist[mapped_lun]);
/*
* If the MappedLUN entry is being disabled, the entry in
* port->sep_alua_list must be removed now before clearing the
@@ -424,17 +415,20 @@ int core_disable_device_list_for_node(
while (atomic_read(&deve->pr_ref_count) != 0)
cpu_relax();
- spin_lock_irq(&nacl->device_list_lock);
/*
* Disable struct se_dev_entry LUN ACL mapping
*/
+ spin_lock_irq(&nacl->lun_entry_lock);
core_scsi3_ua_release_all(deve);
- deve->se_lun = NULL;
- deve->se_lun_acl = NULL;
+ rcu_assign_pointer(deve->se_lun, NULL);
+ rcu_assign_pointer(deve->se_lun_acl, NULL);
deve->lun_flags = 0;
deve->creation_time = 0;
deve->attach_count--;
- spin_unlock_irq(&nacl->device_list_lock);
+ spin_unlock_irq(&nacl->lun_entry_lock);
+ rcu_read_unlock();
+
+ synchronize_rcu();
core_scsi3_free_pr_reg_from_nacl(lun->lun_se_dev, nacl);
return 0;
--
1.9.1
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