target: Make transport_lookup_cmd_lun() locking IRQ-safe
Roland Dreier [Wed, 20 Jul 2011 09:09:10 +0000 (09:09 +0000)]
transport_lookup_cmd_lun() may be called from interrupt context (eg
tcm_loop_allocate_core_cmd() calls it, and it has a comment that says,
"Can be called from interrupt context"), so it needs to use
spin_lock_irqsave() instead of spin_lock_irq() to avoid enabling
interrupts at the wrong time.

(And indeed the last set of lock operations, on lun_cmd_lock, were
already using spin_lock_irqsave(), so we just need to fix the other
two locks we take)

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_device.c

index c674a5d..e25df3b 100644 (file)
@@ -72,7 +72,7 @@ int transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
                return -ENODEV;
        }
 
-       spin_lock_irq(&se_sess->se_node_acl->device_list_lock);
+       spin_lock_irqsave(&se_sess->se_node_acl->device_list_lock, flags);
        se_cmd->se_deve = &se_sess->se_node_acl->device_list[unpacked_lun];
        if (se_cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS) {
                struct se_dev_entry *deve = se_cmd->se_deve;
@@ -88,7 +88,7 @@ int transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
                                " Access for 0x%08x\n",
                                se_cmd->se_tfo->get_fabric_name(),
                                unpacked_lun);
-                       spin_unlock_irq(&se_sess->se_node_acl->device_list_lock);
+                       spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags);
                        return -EACCES;
                }
 
@@ -106,7 +106,7 @@ int transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
                se_cmd->se_orig_obj_ptr = se_cmd->se_lun->lun_se_dev;
                se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD;
        }
-       spin_unlock_irq(&se_sess->se_node_acl->device_list_lock);
+       spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags);
 
        if (!se_lun) {
                /*
@@ -154,13 +154,13 @@ int transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
 
        /* TODO: get rid of this and use atomics for stats */
        dev = se_lun->lun_se_dev;
-       spin_lock_irq(&dev->stats_lock);
+       spin_lock_irqsave(&dev->stats_lock, flags);
        dev->num_cmds++;
        if (se_cmd->data_direction == DMA_TO_DEVICE)
                dev->write_bytes += se_cmd->data_length;
        else if (se_cmd->data_direction == DMA_FROM_DEVICE)
                dev->read_bytes += se_cmd->data_length;
-       spin_unlock_irq(&dev->stats_lock);
+       spin_unlock_irqrestore(&dev->stats_lock, flags);
 
        /*
         * Add the iscsi_cmd_t to the struct se_lun's cmd list.  This list is used