diff mbox

[RFC,2/9] target: use idr for se_device dev index

Message ID 1497262209-5635-3-git-send-email-mchristi@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mike Christie June 12, 2017, 10:10 a.m. UTC
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 it by any old
id. This patch replaces the se_device->dev_index with a idr created
id.

In the next patches I will add helpers so tcmu can look up the
device by that id, and there is an optional patch at the end to
replace the g_device_list with the idr iterator.

Signed-off-by: Mike Christie <mchristi@redhat.com>
---
 drivers/target/target_core_configfs.c |  3 ++
 drivers/target/target_core_device.c   | 53 ++++++++++++++++++++++++++++++++---
 drivers/target/target_core_internal.h |  2 ++
 include/target/target_core_base.h     |  1 -
 4 files changed, 54 insertions(+), 5 deletions(-)
diff mbox

Patch

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 9b8abd5..f075860 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -3196,6 +3196,8 @@  static int __init target_core_init_configfs(void)
 	config_group_init(&subsys->su_group);
 	mutex_init(&subsys->su_mutex);
 
+	target_init_device_idr();
+
 	ret = init_se_kmem_caches();
 	if (ret < 0)
 		return ret;
@@ -3300,6 +3302,7 @@  static void __exit target_core_exit_configfs(void)
 	rd_module_exit();
 	target_xcopy_release_pt();
 	release_se_kmem_caches();
+	target_destroy_device_idr();
 }
 
 MODULE_DESCRIPTION("Target_Core_Mod/ConfigFS");
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 11c80c4..d4090f7 100644
--- 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 struct idr devices_idr;
 
 static struct se_hba *lun0_hba;
 /* not static, needed by tpg.c */
@@ -879,10 +880,20 @@  sector_t target_to_linux_sector(struct se_device *dev, sector_t lb)
 }
 EXPORT_SYMBOL(target_to_linux_sector);
 
+void target_init_device_idr(void)
+{
+	idr_init(&devices_idr);
+}
+
+void target_destroy_device_idr(void)
+{
+	idr_destroy(&devices_idr);
+}
+
 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 +901,28 @@  int target_configure_device(struct se_device *dev)
 		return -EEXIST;
 	}
 
+	/*
+	 * Add early so modules like tcmu can use during its
+	 * configuration.
+	 */
+	idr_preload(GFP_KERNEL);
+	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);
+	idr_preload_end();
+	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 +937,11 @@  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 +989,10 @@  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;
@@ -968,10 +1001,12 @@  int target_configure_device(struct se_device *dev)
 void target_free_device(struct se_device *dev)
 {
 	struct se_hba *hba = dev->se_hba;
+	int dev_index = -1;
 
 	WARN_ON(!list_empty(&dev->dev_sep_list));
 
 	if (dev->dev_flags & DF_CONFIGURED) {
+		dev_index = dev->dev_index;
 		destroy_workqueue(dev->tmr_wq);
 
 		mutex_lock(&g_device_mutex);
@@ -992,6 +1027,16 @@  void target_free_device(struct se_device *dev)
 		dev->transport->free_prot(dev);
 
 	dev->transport->free_device(dev);
+
+	/*
+	 * We have to delay removal in case the free_device callout needs
+	 * to use it.
+	 */
+	if (dev_index >= 0) {
+		mutex_lock(&g_device_mutex);
+		idr_remove(&devices_idr, dev_index);
+		mutex_unlock(&g_device_mutex);
+	}
 }
 
 int core_dev_setup_virtual_lun0(void)
diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index 0912de7..dfa923b 100644
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -132,6 +132,8 @@  struct se_node_acl *core_tpg_add_initiator_node_acl(struct se_portal_group *tpg,
 /* target_core_transport.c */
 extern struct kmem_cache *se_tmr_req_cache;
 
+void	target_init_device_idr(void);
+void	target_destroy_device_idr(void);
 int	init_se_kmem_caches(void);
 void	release_se_kmem_caches(void);
 u32	scsi_get_new_index(scsi_index_t);
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index a3af69f..51a92f1 100644
--- 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;