From: Jeff Dike The registration of host network transports needed some locking. The transport list itself is locked, but calls to the registration routines are not. This is compensated for by checking that a transport structure is not yet on any list. I also took the opportunity to const all fields in the transport structure except the list, which obviously can be modified. Signed-off-by: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton --- arch/um/drivers/net_kern.c | 9 +++++---- arch/um/include/net_kern.h | 8 ++++---- 2 files changed, 9 insertions(+), 8 deletions(-) diff -puN arch/um/drivers/net_kern.c~uml-add-locking-to-network-transport-registration arch/um/drivers/net_kern.c --- a/arch/um/drivers/net_kern.c~uml-add-locking-to-network-transport-registration +++ a/arch/um/drivers/net_kern.c @@ -498,10 +498,8 @@ struct eth_init { int index; }; -/* Filled in at boot time. Will need locking if the transports become - * modular. - */ -struct list_head transports = LIST_HEAD_INIT(transports); +static DEFINE_SPINLOCK(transports_lock); +static LIST_HEAD(transports); /* Filled in during early boot */ struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line); @@ -540,7 +538,10 @@ void register_transport(struct transport char *mac = NULL; int match; + spin_lock(&transports_lock); + BUG_ON(!list_empty(&new->list)); list_add(&new->list, &transports); + spin_unlock(&transports_lock); list_for_each_safe(ele, next, ð_cmd_line){ eth = list_entry(ele, struct eth_init, list); diff -puN arch/um/include/net_kern.h~uml-add-locking-to-network-transport-registration arch/um/include/net_kern.h --- a/arch/um/include/net_kern.h~uml-add-locking-to-network-transport-registration +++ a/arch/um/include/net_kern.h @@ -52,12 +52,12 @@ struct net_kern_info { struct transport { struct list_head list; - char *name; - int (*setup)(char *, char **, void *); + const char *name; + int (* const setup)(char *, char **, void *); const struct net_user_info *user; const struct net_kern_info *kern; - int private_size; - int setup_size; + const int private_size; + const int setup_size; }; extern struct net_device *ether_init(int); _