======= Locking

This file explains the locking and exclusion scheme used in the PCCARD and PCMCIA subsystems.

A) Overview, Locking Hierarchy:

pcmcia_socket_list_rwsem - protects only the list of sockets

• skt_mutex

  • serializes card insert / ejection

  • ops_mutex

    • serializes socket operation

B) Exclusion

The following functions and callbacks to struct pcmcia_socket must be called with "skt_mutex" held::

socket_detect_change()
send_event()
socket_reset()
socket_shutdown()
socket_setup()
socket_remove()
socket_insert()
socket_early_resume()
socket_late_resume()
socket_resume()
socket_suspend()

struct pcmcia_callback	*callback

The following functions and callbacks to struct pcmcia_socket must be called with "ops_mutex" held::

socket_reset()
socket_setup()

struct pccard_operations	*ops
struct pccard_resource_ops	*resource_ops;

Note that send_event() and struct pcmcia_callback *callback must not be called with "ops_mutex" held.

C) Protection

1. Global Data:

struct list_head pcmcia_socket_list;

protected by pcmcia_socket_list_rwsem;

2. Per-Socket Data:

The resource_ops and their data are protected by ops_mutex.

The "main" struct pcmcia_socket is protected as follows (read-only fields or single-use fields not mentioned):

• by pcmcia_socket_list_rwsem::

  struct list_head socket_list;

• by thread_lock::

  unsigned int thread_events;

• by skt_mutex::

  u_int suspended_state; void (*tune_bridge); struct pcmcia_callback *callback; int resume_status;

• by ops_mutex::

  socket_state_t socket; u_int state; u_short lock_count; pccard_mem_map cis_mem; void __iomem *cis_virt; struct { } irq; io_window_t io[]; pccard_mem_map win[]; struct list_head cis_cache; size_t fake_cis_len; u8 *fake_cis; u_int irq_mask; void (*zoom_video); int (*power_hook); u8 resource...; struct list_head devices_list; u8 device_count; struct pcmcia_state;

3. Per PCMCIA-device Data:

The "main" struct pcmcia_device is protected as follows (read-only fields or single-use fields not mentioned):

• by pcmcia_socket->ops_mutex::

  struct list_head socket_device_list; struct config_t *function_config; u16 _irq:1; u16 _io:1; u16 _win:4; u16 _locked:1; u16 allow_func_id_match:1; u16 suspended:1; u16 _removed:1;

• by the PCMCIA driver::

  io_req_t io; irq_req_t irq; config_req_t conf; window_handle_t win;