From 3d068261854b00c930df4516cd617900935e7706 Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Sat, 16 Jan 2010 09:17:10 +0100 Subject: pcmcia: add locking documentation Tested-by: Wolfram Sang Signed-off-by: Dominik Brodowski --- Documentation/pcmcia/locking.txt | 92 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 Documentation/pcmcia/locking.txt (limited to 'Documentation') diff --git a/Documentation/pcmcia/locking.txt b/Documentation/pcmcia/locking.txt new file mode 100644 index 00000000000..5f25de4cdb4 --- /dev/null +++ b/Documentation/pcmcia/locking.txt @@ -0,0 +1,92 @@ +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 + +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 are on their own to provide proper locking. + +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; -- cgit v1.2.3 From 94a819f80297e1f635a7cde4ed5317612e512ba7 Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Sun, 17 Jan 2010 18:31:34 +0100 Subject: pcmcia: assert locking to struct pcmcia_device Tested-by: Wolfram Sang Signed-off-by: Dominik Brodowski --- Documentation/pcmcia/locking.txt | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'Documentation') diff --git a/Documentation/pcmcia/locking.txt b/Documentation/pcmcia/locking.txt index 5f25de4cdb4..d6251056128 100644 --- a/Documentation/pcmcia/locking.txt +++ b/Documentation/pcmcia/locking.txt @@ -90,3 +90,28 @@ or single-use fields not mentioned): struct list_head devices_list; u8 device_count; struct pcmcia_state; + + +3. Per PCMCIA-device Data: +-------------------------- + +The "main" struct pcmcia_devie 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; -- cgit v1.2.3 From cfe5d809518eda3d5e2da87c5ccbe8647143573a Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Sun, 17 Jan 2010 19:31:45 +0100 Subject: pcmcia: use ops_mutex for rsrc_{mgr,nonstatic} locking Tested-by: Wolfram Sang Signed-off-by: Dominik Brodowski --- Documentation/pcmcia/locking.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/pcmcia/locking.txt b/Documentation/pcmcia/locking.txt index d6251056128..68f622bc406 100644 --- a/Documentation/pcmcia/locking.txt +++ b/Documentation/pcmcia/locking.txt @@ -36,7 +36,8 @@ be called with "ops_mutex" held: socket_reset() socket_setup() - struct pccard_operations *ops + 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. @@ -54,7 +55,7 @@ protected by pcmcia_socket_list_rwsem; 2. Per-Socket Data: ------------------- -The resource_ops are on their own to provide proper locking. +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): -- cgit v1.2.3