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greybus: protocol: add a module owner to a protocol

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Now that protocols can be in a module, we need to reference count them
to lock them into memory so they can't be removed while in use.  So add
a module owner structure, and have it automatically be assigned when
registering the protocol.

Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
Reviewed-by: Alex Elder <elder@linaro.org>
This commit is contained in:
Greg Kroah-Hartman 2014-12-24 13:01:40 -08:00
parent 1b6ea0db01
commit 12a5dfc9ac
2 changed files with 17 additions and 6 deletions
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17
drivers/staging/greybus/protocol.c
View File

@ -39,13 +39,15 @@ static struct gb_protocol *_gb_protocol_find(u8 id, u8 major, u8 minor)
return NULL;
}
int gb_protocol_register(struct gb_protocol *protocol)
int __gb_protocol_register(struct gb_protocol *protocol, struct module *module)
{
struct gb_protocol *existing;
u8 id = protocol->id;
u8 major = protocol->major;
u8 minor = protocol->minor;
protocol->owner = module;
/*
* The protocols list is sorted first by protocol id (low to
* high), then by major version (high to low), and finally
@ -92,7 +94,7 @@ int gb_protocol_register(struct gb_protocol *protocol)
return 0;
}
EXPORT_SYMBOL_GPL(gb_protocol_register);
EXPORT_SYMBOL_GPL(__gb_protocol_register);
/*
* De-register a previously registered protocol.
@ -135,9 +137,13 @@ struct gb_protocol *gb_protocol_get(u8 id, u8 major, u8 minor)
spin_lock_irq(&gb_protocols_lock);
protocol = _gb_protocol_find(id, major, minor);
if (protocol) {
protocol_count = protocol->count;
if (protocol_count != U8_MAX)
protocol->count++;
if (!try_module_get(protocol->owner)) {
protocol = NULL;
} else {
protocol_count = protocol->count;
if (protocol_count != U8_MAX)
protocol->count++;
}
}
spin_unlock_irq(&gb_protocols_lock);
@ -163,6 +169,7 @@ void gb_protocol_put(struct gb_protocol *protocol)
protocol_count = protocol->count;
if (protocol_count)
protocol->count--;
module_put(protocol->owner);
}
spin_unlock_irq(&gb_protocols_lock);
if (protocol)

6
drivers/staging/greybus/protocol.h
View File

@ -34,11 +34,15 @@ struct gb_protocol {
gb_connection_init_t connection_init;
gb_connection_exit_t connection_exit;
gb_request_recv_t request_recv;
struct module *owner;
};
int gb_protocol_register(struct gb_protocol *protocol);
int __gb_protocol_register(struct gb_protocol *protocol, struct module *module);
int gb_protocol_deregister(struct gb_protocol *protocol);
#define gb_protocol_register(protocol) \
__gb_protocol_register(protocol, THIS_MODULE)
struct gb_protocol *gb_protocol_get(u8 id, u8 major, u8 minor);
void gb_protocol_put(struct gb_protocol *protocol);