linux/drivers/target/iscsi/iscsi_target_transport.c
Nicholas Bellinger 3f99306337 iscsi-target: Add iscsit_transport API template
Add basic struct iscsit_transport API template to allow iscsi-target for
running with external transport modules using existing iscsi_target_core.h
code.

For all external modules, this calls try_module_get() and module_put()
to obtain + release an external iscsit_transport module reference count.

Also include the iscsi-target symbols necessary in iscsi_transport.h to
allow external transport modules to function.

v3 changes:
- Add iscsit_build_reject export for ISTATE_SEND_REJECT usage

v2 changes:

- Drop unnecessary export of iscsit_get_transport + iscsit_put_transport (roland)
- Add ->iscsit_queue_data_in() to remove extra context switch on RDMA_WRITE
- Add ->iscsit_queue_status() to remove extra context switch on IB_SEND status
- Add ->iscsit_get_dataout() to remove extra context switch on RDMA_READ
- Drop ->iscsit_free_cmd()
- Drop ->iscsit_unmap_cmd()
- Rename iscsit_create_transport() -> iscsit_register_transport() (andy)
- Rename iscsit_destroy_transport() -> iscsit_unregister_transport() (andy)

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-04-25 01:05:26 -07:00

56 lines
1.2 KiB
C

#include <linux/spinlock.h>
#include <linux/list.h>
#include <target/iscsi/iscsi_transport.h>
static LIST_HEAD(g_transport_list);
static DEFINE_MUTEX(transport_mutex);
struct iscsit_transport *iscsit_get_transport(int type)
{
struct iscsit_transport *t;
mutex_lock(&transport_mutex);
list_for_each_entry(t, &g_transport_list, t_node) {
if (t->transport_type == type) {
if (t->owner && !try_module_get(t->owner)) {
t = NULL;
}
mutex_unlock(&transport_mutex);
return t;
}
}
mutex_unlock(&transport_mutex);
return NULL;
}
void iscsit_put_transport(struct iscsit_transport *t)
{
if (t->owner)
module_put(t->owner);
}
int iscsit_register_transport(struct iscsit_transport *t)
{
INIT_LIST_HEAD(&t->t_node);
mutex_lock(&transport_mutex);
list_add_tail(&t->t_node, &g_transport_list);
mutex_unlock(&transport_mutex);
pr_debug("Registered iSCSI transport: %s\n", t->name);
return 0;
}
EXPORT_SYMBOL(iscsit_register_transport);
void iscsit_unregister_transport(struct iscsit_transport *t)
{
mutex_lock(&transport_mutex);
list_del(&t->t_node);
mutex_unlock(&transport_mutex);
pr_debug("Unregistered iSCSI transport: %s\n", t->name);
}
EXPORT_SYMBOL(iscsit_unregister_transport);