target: use idr for se_device dev index

In the next patches we will add tcmu netlink support that allows
userspace to send commands to target_core_user. To execute operations
on a se_device/tcmu_dev we need to be able to look up a dev by any old
id. This patch replaces the se_device->dev_index with a idr created
id.

The next patches will also remove the g_device_list and replace it with
the idr.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 16a701fed66b265d7813f3c4c13d0d1a23be1bfb..f10dfe7b1d54e2916afc5f9106a84027551f700e 100644 (file)
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -51,6 +51,7 @@
 
 DEFINE_MUTEX(g_device_mutex);
 LIST_HEAD(g_device_list);
+static DEFINE_IDR(devices_idr);
 
 static struct se_hba *lun0_hba;
 /* not static, needed by tpg.c */
@@ -882,7 +883,7 @@ EXPORT_SYMBOL(target_to_linux_sector);
 int target_configure_device(struct se_device *dev)
 {
        struct se_hba *hba = dev->se_hba;
-       int ret;
+       int ret, id;
 
        if (dev->dev_flags & DF_CONFIGURED) {
                pr_err("se_dev->se_dev_ptr already set for storage"
@@ -890,9 +891,26 @@ int target_configure_device(struct se_device *dev)
                return -EEXIST;
        }
 
+       /*
+        * Add early so modules like tcmu can use during its
+        * configuration.
+        */
+       mutex_lock(&g_device_mutex);
+       /*
+        * Use cyclic to try and avoid collisions with devices
+        * that were recently removed.
+        */
+       id = idr_alloc_cyclic(&devices_idr, dev, 0, INT_MAX, GFP_KERNEL);
+       mutex_unlock(&g_device_mutex);
+       if (id < 0) {
+               ret = -ENOMEM;
+               goto out;
+       }
+       dev->dev_index = id;
+
        ret = dev->transport->configure_device(dev);
        if (ret)
-               goto out;
+               goto out_free_index;
        /*
         * XXX: there is not much point to have two different values here..
         */
@@ -907,12 +925,11 @@ int target_configure_device(struct se_device *dev)
                                         dev->dev_attrib.hw_block_size);
        dev->dev_attrib.optimal_sectors = dev->dev_attrib.hw_max_sectors;
 
-       dev->dev_index = scsi_get_new_index(SCSI_DEVICE_INDEX);
        dev->creation_time = get_jiffies_64();
 
        ret = core_setup_alua(dev);
        if (ret)
-               goto out;
+               goto out_free_index;
 
        /*
         * Startup the struct se_device processing thread
@@ -960,6 +977,10 @@ int target_configure_device(struct se_device *dev)
 
 out_free_alua:
        core_alua_free_lu_gp_mem(dev);
+out_free_index:
+       mutex_lock(&g_device_mutex);
+       idr_remove(&devices_idr, dev->dev_index);
+       mutex_unlock(&g_device_mutex);
 out:
        se_release_vpd_for_dev(dev);
        return ret;
@@ -977,6 +998,7 @@ void target_free_device(struct se_device *dev)
                dev->transport->destroy_device(dev);
 
                mutex_lock(&g_device_mutex);
+               idr_remove(&devices_idr, dev->dev_index);
                list_del(&dev->g_dev_node);
                mutex_unlock(&g_device_mutex);
 

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index a3af69fcf75e463acb5cb4f530e6aca3ab7dfb9a..51a92f17352c29c06ba6828dea8ef337ae0d7302 100644 (file)
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -219,7 +219,6 @@ enum tcm_tmrsp_table {
  */
 typedef enum {
        SCSI_INST_INDEX,
-       SCSI_DEVICE_INDEX,
        SCSI_AUTH_INTR_INDEX,
        SCSI_INDEX_TYPE_MAX
 } scsi_index_t;