diff options
| -rw-r--r-- | drivers/firewire/core-transaction.c | 13 | ||||
| -rw-r--r-- | include/linux/firewire.h | 12 |
2 files changed, 18 insertions, 7 deletions
diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c index d39cfa45817..28a94c7ec6e 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); diff --git a/include/linux/firewire.h b/include/linux/firewire.h index db04ec5121c..191501afd7f 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -265,8 +265,16 @@ typedef void (*fw_transaction_callback_t)(struct fw_card *card, int rcode, void *data, size_t length, void *callback_data); /* - * Important note: Except for the FCP registers, the callback must guarantee - * that either fw_send_response() or kfree() is called on the @request. + * This callback handles an inbound request subaction. It is called in + * RCU read-side context, therefore must not sleep. + * + * The callback should not initiate outbound request subactions directly. + * Otherwise there is a danger of recursion of inbound and outbound + * transactions from and to the local node. + * + * The callback is responsible that either fw_send_response() or kfree() + * is called on the @request, except for FCP registers for which the core + * takes care of that. */ typedef void (*fw_address_callback_t)(struct fw_card *card, struct fw_request *request, |