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Subject[PATCH 06/21] target: Remove unnecessary hba_dev_list walk and se_clear_dev_ports legacy code
Date
From: Fubo Chen <fubo.chen@gmail.com>

This patch removes a legacy struct se_hba->hba_dev_list -> se_release_device_for_hba()
list walk in core_delete_hba(), which is no longer required while using configfs
VFS level parent/child struct config_group dependency referencing. The reason
is because any struct se_hba->hba_dev_list-> struct se_device members are going
to have to be released via:

rmdir /sys/kernel/config/target/core/$HBA/*

before rmdir release of struct se_hba via target_core_configfs.c:
target_core_call_delhbafromtarget() -> core_delete_hba()

rmdir /sys/kernel/config/target/core/$HBA

to release struct se_hba in core_delete_hba().

This patch also removes the legacy se_clear_dev_ports() function, which is
left-over pre-configfs shutdown logic for when se_free_virtual_device()
was responsible for walking struct se_device->dev_sep_list and calling
core_dev_del_lun() for each individual active struct se_port->se_lun.

The reason this can be removed is because all struct se_device->dev_sep_list
-> struct se_port communication is done via configfs symlinks, which
means that an target fabric module's endpoints containg active struct
se_port(s) will have to be released via target_core_fabric_configfs.c:
target_fabric_port_unlink() via:

unlink /sys/kernel/config/target/$FABRIC_MOD/$ENDPOINT/tpgt_$TPGT/lun/lun_$LUN_ID/<symlink>

before rmdir release of struct se_device in target_core_configfs.c:
target_core_drop_subdev() -> se_free_virtual_device() can happen via:

rmdir /sys/kernel/config/target/core/$HBA/*

to release struct se_subsystem_dev in target_core_drop_subdev()

Reported-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Reported-by: Fubo Chen <fubo.chen@gmail.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
---
drivers/target/target_core_device.c | 39 +---------------------------------
drivers/target/target_core_hba.c | 15 +-----------
2 files changed, 4 insertions(+), 50 deletions(-)

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 5da051a..c9085e3 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -780,49 +780,14 @@ void se_release_vpd_for_dev(struct se_device *dev)
return;
}

-/*
- * Called with struct se_hba->device_lock held.
- */
-void se_clear_dev_ports(struct se_device *dev)
-{
- struct se_hba *hba = dev->se_hba;
- struct se_lun *lun;
- struct se_portal_group *tpg;
- struct se_port *sep, *sep_tmp;
-
- spin_lock(&dev->se_port_lock);
- list_for_each_entry_safe(sep, sep_tmp, &dev->dev_sep_list, sep_list) {
- spin_unlock(&dev->se_port_lock);
- spin_unlock(&hba->device_lock);
-
- lun = sep->sep_lun;
- tpg = sep->sep_tpg;
- spin_lock(&lun->lun_sep_lock);
- if (lun->lun_se_dev == NULL) {
- spin_unlock(&lun->lun_sep_lock);
- continue;
- }
- spin_unlock(&lun->lun_sep_lock);
-
- core_dev_del_lun(tpg, lun->unpacked_lun);
-
- spin_lock(&hba->device_lock);
- spin_lock(&dev->se_port_lock);
- }
- spin_unlock(&dev->se_port_lock);
-
- return;
-}
-
/* se_free_virtual_device():
*
* Used for IBLOCK, RAMDISK, and FILEIO Transport Drivers.
*/
int se_free_virtual_device(struct se_device *dev, struct se_hba *hba)
{
- spin_lock(&hba->device_lock);
- se_clear_dev_ports(dev);
- spin_unlock(&hba->device_lock);
+ if (!list_empty(&dev->dev_sep_list))
+ dump_stack();

core_alua_free_lu_gp_mem(dev);
se_release_device_for_hba(dev);
diff --git a/drivers/target/target_core_hba.c b/drivers/target/target_core_hba.c
index 4bbe820..d0d2ecc 100644
--- a/drivers/target/target_core_hba.c
+++ b/drivers/target/target_core_hba.c
@@ -153,19 +153,8 @@ out_free_hba:
int
core_delete_hba(struct se_hba *hba)
{
- struct se_device *dev, *dev_tmp;
-
- spin_lock(&hba->device_lock);
- list_for_each_entry_safe(dev, dev_tmp, &hba->hba_dev_list, dev_list) {
-
- se_clear_dev_ports(dev);
- spin_unlock(&hba->device_lock);
-
- se_release_device_for_hba(dev);
-
- spin_lock(&hba->device_lock);
- }
- spin_unlock(&hba->device_lock);
+ if (!list_empty(&hba->hba_dev_list))
+ dump_stack();

hba->transport->detach_hba(hba);

--
1.7.4.1


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