From 4d50c44381c981c9caa74e82ab894d4938dac9ca Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Thu, 27 Sep 2012 21:46:09 +0200 Subject: firewire: addendum to address handler RCU conversion Follow up on commit c285f6ff6787 "firewire: remove global lock around address handlers, convert to RCU": - address_handler_lock no longer serializes the address handler, only its function to serialize updates to the list of handlers remains. Rename the lock to address_handler_list_lock. - Callers of fw_core_remove_address_handler() must be able to sleep. Comment on this in the API documentation. - The counterpart fw_core_add_address_handler() is by nature something which is used in process context. Replace spin_lock_bh() by spin_lock() in fw_core_add_address_handler() and in fw_core_remove_address_handler(), and document that process context is now required for fw_core_add_address_handler(). - Extend the documentation of fw_address_callback_t. Signed-off-by: Stefan Richter --- drivers/firewire/core-transaction.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'drivers/firewire') diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c index d39cfa45817a..28a94c7ec6e5 100644 --- a/drivers/firewire/core-transaction.c +++ b/drivers/firewire/core-transaction.c @@ -519,7 +519,7 @@ static struct fw_address_handler *lookup_enclosing_address_handler( return NULL; } -static DEFINE_SPINLOCK(address_handler_lock); +static DEFINE_SPINLOCK(address_handler_list_lock); static LIST_HEAD(address_handler_list); const struct fw_address_region fw_high_memory_region = @@ -556,6 +556,7 @@ static bool is_in_fcp_region(u64 offset, size_t length) * the specified callback is invoked. The parameters passed to the callback * give the details of the particular request. * + * To be called in process context. * Return value: 0 on success, non-zero otherwise. * * The start offset of the handler's address region is determined by @@ -576,7 +577,7 @@ int fw_core_add_address_handler(struct fw_address_handler *handler, handler->length == 0) return -EINVAL; - spin_lock_bh(&address_handler_lock); + spin_lock(&address_handler_list_lock); handler->offset = region->start; while (handler->offset + handler->length <= region->end) { @@ -595,7 +596,7 @@ int fw_core_add_address_handler(struct fw_address_handler *handler, } } - spin_unlock_bh(&address_handler_lock); + spin_unlock(&address_handler_list_lock); return ret; } @@ -604,14 +605,16 @@ EXPORT_SYMBOL(fw_core_add_address_handler); /** * fw_core_remove_address_handler() - unregister an address handler * + * To be called in process context. + * * When fw_core_remove_address_handler() returns, @handler->callback() is * guaranteed to not run on any CPU anymore. */ void fw_core_remove_address_handler(struct fw_address_handler *handler) { - spin_lock_bh(&address_handler_lock); + spin_lock(&address_handler_list_lock); list_del_rcu(&handler->link); - spin_unlock_bh(&address_handler_lock); + spin_unlock(&address_handler_list_lock); synchronize_rcu(); } EXPORT_SYMBOL(fw_core_remove_address_handler); -- cgit v1.2.3