scsi: target: Remove se_dev_entry.ua_count

se_dev_entry.ua_count is only used to check whether or not
se_dev_entry.ua_list is empty. Use list_empty_careful() instead.  Checking
whether or not ua_list is empty without holding the lock that protects that
list is fine because the code that dequeues from that list will check again
whether or not that list is empty.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index e5c90af..73675ee 100644 (file)
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -336,7 +336,6 @@ int core_enable_device_list_for_node(
                return -ENOMEM;
        }
 
-       atomic_set(&new->ua_count, 0);
        spin_lock_init(&new->ua_lock);
        INIT_LIST_HEAD(&new->ua_list);
        INIT_LIST_HEAD(&new->lun_link);

diff --git a/drivers/target/target_core_ua.c b/drivers/target/target_core_ua.c
index 9399b38..c8ac242 100644 (file)
--- a/drivers/target/target_core_ua.c
+++ b/drivers/target/target_core_ua.c
@@ -55,7 +55,7 @@ target_scsi3_ua_check(struct se_cmd *cmd)
                rcu_read_unlock();
                return 0;
        }
-       if (!atomic_read(&deve->ua_count)) {
+       if (list_empty_careful(&deve->ua_list)) {
                rcu_read_unlock();
                return 0;
        }
@@ -154,7 +154,6 @@ int core_scsi3_ua_allocate(
                                &deve->ua_list);
                spin_unlock(&deve->ua_lock);
 
-               atomic_inc_mb(&deve->ua_count);
                return 0;
        }
        list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
@@ -164,7 +163,6 @@ int core_scsi3_ua_allocate(
                " 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
                asc, ascq);
 
-       atomic_inc_mb(&deve->ua_count);
        return 0;
 }
 
@@ -196,8 +194,6 @@ void core_scsi3_ua_release_all(
        list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
                list_del(&ua->ua_nacl_list);
                kmem_cache_free(se_ua_cache, ua);
-
-               atomic_dec_mb(&deve->ua_count);
        }
        spin_unlock(&deve->ua_lock);
 }
@@ -263,8 +259,6 @@ bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
                }
                list_del(&ua->ua_nacl_list);
                kmem_cache_free(se_ua_cache, ua);
-
-               atomic_dec_mb(&deve->ua_count);
        }
        spin_unlock(&deve->ua_lock);
        rcu_read_unlock();
@@ -304,7 +298,7 @@ int core_scsi3_ua_clear_for_request_sense(
                rcu_read_unlock();
                return -EINVAL;
        }
-       if (!atomic_read(&deve->ua_count)) {
+       if (list_empty_careful(&deve->ua_list)) {
                rcu_read_unlock();
                return -EPERM;
        }
@@ -327,8 +321,6 @@ int core_scsi3_ua_clear_for_request_sense(
                }
                list_del(&ua->ua_nacl_list);
                kmem_cache_free(se_ua_cache, ua);
-
-               atomic_dec_mb(&deve->ua_count);
        }
        spin_unlock(&deve->ua_lock);
        rcu_read_unlock();

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index ca59e06..7a4ee78 100644 (file)
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -638,7 +638,6 @@ struct se_dev_entry {
        atomic_long_t           total_cmds;
        atomic_long_t           read_bytes;
        atomic_long_t           write_bytes;
-       atomic_t                ua_count;
        /* Used for PR SPEC_I_PT=1 and REGISTER_AND_MOVE */
        struct kref             pr_kref;
        struct completion       pr_comp;