[03/12] target: use idr for se_device dev index

Commit Message

Mike Christie June 21, 2017, 9:33 p.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 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 <[e-mail]>
---

Changes:
- Drop target_init_device_idr/target_destroy_device_idr and use DEFINE_IDR.

 drivers/target/target_core_device.c | 30 ++++++++++++++++++++++++++----
 include/target/target_core_base.h   |  1 -
 2 files changed, 26 insertions(+), 5 deletions(-)

Comments

Mike Christie June 21, 2017, 9:40 p.m. UTC | #1

On 06/21/2017 04:33 PM, Mike Christie wrote:
> 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 <[e-mail]>
> ---
> 
> Changes:
> - Drop target_init_device_idr/target_destroy_device_idr and use DEFINE_IDR.
> 
>  drivers/target/target_core_device.c | 30 ++++++++++++++++++++++++++----
>  include/target/target_core_base.h   |  1 -
>  2 files changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
> index 16a701f..d6fc8c0 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);
> +DEFINE_IDR(devices_idr);
>  

Nick and Bart,

Shoot. I posted the wrong version. That was supposed to be

static DEFINE_IDR(devices_idr);

That then breaks some other patches down the line.

I will resend.

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Patch

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 16a701f..d6fc8c0 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);
+DEFINE_IDR(devices_idr);
 
 static struct se_hba *lun0_hba;
 /* not static, needed by tpg.c */
@@ -882,7 +883,7 @@  sector_t target_to_linux_sector(struct se_device *dev, sector_t lb)
 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 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;