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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-02-28 01:18:30 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-02-28 01:18:30 +0100 |
commit | 8d37a371b6869920e6c40c495c68eabba1ef3909 (patch) | |
tree | dad784512b13832f4f5494cfe0791965c6a2b0f6 /Documentation | |
parent | Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/pow... (diff) | |
parent | pcmcia: validate late-added resources (diff) | |
download | linux-8d37a371b6869920e6c40c495c68eabba1ef3909.tar.xz linux-8d37a371b6869920e6c40c495c68eabba1ef3909.zip |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6: (49 commits)
pcmcia: validate late-added resources
pcmcia: allow for extension of resource interval
pcmcia: remove useless msleep in ds.c
pcmcia: use read_cis_mem return value
pcmcia: handle error in serial_cs config calls
pcmcia: add locking to pcmcia_{read,write}_cis_mem
pcmcia: avoid prod_id memleak
pcmcia: avoid sysfs-related lockup for cardbus
pcmcia: use state machine for extended requery
pcmcia: delay re-scanning and re-querying of PCMCIA bus
pcmcia: use pccardd to handle eject, insert, suspend and resume requests
pcmcia: use ops_mutex for rsrc_{mgr,nonstatic} locking
pcmcia: use mutex for dynid lock
pcmcia: assert locking to struct pcmcia_device
pcmcia: add locking documentation
pcmcia: simplify locking
pcmcia: add locking to struct pcmcia_socket->pcmcia_state()
pcmcia: protect s->device_count
pcmcia: properly lock skt->irq, skt->irq_mask
pcmcia: lock ops->set_socket
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/pcmcia/locking.txt | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/Documentation/pcmcia/locking.txt b/Documentation/pcmcia/locking.txt new file mode 100644 index 000000000000..68f622bc4064 --- /dev/null +++ b/Documentation/pcmcia/locking.txt @@ -0,0 +1,118 @@ +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_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; |