target: use save/restore lock primitive in core_dec_lacl_count()

It may happen that uasp will free the request in irq conntext, the
callchain:

 uasp_cmd_release() -> transport_generic_free_cmd() -> core_dec_lacl_count()

where the last function enables the IRQ. Those irqs are re-disabled
later (due to the spin.*irq_restore) but in between we could get hurt.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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 0c5992f..00159a4 100644 (file)
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -320,11 +320,12 @@ int core_free_device_list_for_node(
 void core_dec_lacl_count(struct se_node_acl *se_nacl, struct se_cmd *se_cmd)
 {
        struct se_dev_entry *deve;
+       unsigned long flags;
 
-       spin_lock_irq(&se_nacl->device_list_lock);
+       spin_lock_irqsave(&se_nacl->device_list_lock, flags);
        deve = &se_nacl->device_list[se_cmd->orig_fe_lun];
        deve->deve_cmds--;
-       spin_unlock_irq(&se_nacl->device_list_lock);
+       spin_unlock_irqrestore(&se_nacl->device_list_lock, flags);
 }
 
 void core_update_device_list_access(