diff options
Diffstat (limited to 'net/rxrpc/ar-call.c')
-rw-r--r-- | net/rxrpc/ar-call.c | 158 |
1 files changed, 62 insertions, 96 deletions
diff --git a/net/rxrpc/ar-call.c b/net/rxrpc/ar-call.c index 1fbaae1..68125dc 100644 --- a/net/rxrpc/ar-call.c +++ b/net/rxrpc/ar-call.c @@ -196,6 +196,43 @@ struct rxrpc_call *rxrpc_find_call_hash( } /* + * find an extant server call + * - called in process context with IRQs enabled + */ +struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *rx, + unsigned long user_call_ID) +{ + struct rxrpc_call *call; + struct rb_node *p; + + _enter("%p,%lx", rx, user_call_ID); + + read_lock(&rx->call_lock); + + p = rx->calls.rb_node; + while (p) { + call = rb_entry(p, struct rxrpc_call, sock_node); + + if (user_call_ID < call->user_call_ID) + p = p->rb_left; + else if (user_call_ID > call->user_call_ID) + p = p->rb_right; + else + goto found_extant_call; + } + + read_unlock(&rx->call_lock); + _leave(" = NULL"); + return NULL; + +found_extant_call: + rxrpc_get_call(call); + read_unlock(&rx->call_lock); + _leave(" = %p [%d]", call, atomic_read(&call->usage)); + return call; +} + +/* * allocate a new call */ static struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp) @@ -311,51 +348,27 @@ static struct rxrpc_call *rxrpc_alloc_client_call( * set up a call for the given data * - called in process context with IRQs enabled */ -struct rxrpc_call *rxrpc_get_client_call(struct rxrpc_sock *rx, +struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, struct rxrpc_transport *trans, struct rxrpc_conn_bundle *bundle, unsigned long user_call_ID, - int create, gfp_t gfp) { - struct rxrpc_call *call, *candidate; - struct rb_node *p, *parent, **pp; + struct rxrpc_call *call, *xcall; + struct rb_node *parent, **pp; - _enter("%p,%d,%d,%lx,%d", - rx, trans ? trans->debug_id : -1, bundle ? bundle->debug_id : -1, - user_call_ID, create); + _enter("%p,%d,%d,%lx", + rx, trans->debug_id, bundle ? bundle->debug_id : -1, + user_call_ID); - /* search the extant calls first for one that matches the specified - * user ID */ - read_lock(&rx->call_lock); - - p = rx->calls.rb_node; - while (p) { - call = rb_entry(p, struct rxrpc_call, sock_node); - - if (user_call_ID < call->user_call_ID) - p = p->rb_left; - else if (user_call_ID > call->user_call_ID) - p = p->rb_right; - else - goto found_extant_call; + call = rxrpc_alloc_client_call(rx, trans, bundle, gfp); + if (IS_ERR(call)) { + _leave(" = %ld", PTR_ERR(call)); + return call; } - read_unlock(&rx->call_lock); - - if (!create || !trans) - return ERR_PTR(-EBADSLT); - - /* not yet present - create a candidate for a new record and then - * redo the search */ - candidate = rxrpc_alloc_client_call(rx, trans, bundle, gfp); - if (IS_ERR(candidate)) { - _leave(" = %ld", PTR_ERR(candidate)); - return candidate; - } - - candidate->user_call_ID = user_call_ID; - __set_bit(RXRPC_CALL_HAS_USERID, &candidate->flags); + call->user_call_ID = user_call_ID; + __set_bit(RXRPC_CALL_HAS_USERID, &call->flags); write_lock(&rx->call_lock); @@ -363,19 +376,16 @@ struct rxrpc_call *rxrpc_get_client_call(struct rxrpc_sock *rx, parent = NULL; while (*pp) { parent = *pp; - call = rb_entry(parent, struct rxrpc_call, sock_node); + xcall = rb_entry(parent, struct rxrpc_call, sock_node); - if (user_call_ID < call->user_call_ID) + if (user_call_ID < xcall->user_call_ID) pp = &(*pp)->rb_left; - else if (user_call_ID > call->user_call_ID) + else if (user_call_ID > xcall->user_call_ID) pp = &(*pp)->rb_right; else - goto found_extant_second; + goto found_user_ID_now_present; } - /* second search also failed; add the new call */ - call = candidate; - candidate = NULL; rxrpc_get_call(call); rb_link_node(&call->sock_node, parent, pp); @@ -391,20 +401,16 @@ struct rxrpc_call *rxrpc_get_client_call(struct rxrpc_sock *rx, _leave(" = %p [new]", call); return call; - /* we found the call in the list immediately */ -found_extant_call: - rxrpc_get_call(call); - read_unlock(&rx->call_lock); - _leave(" = %p [extant %d]", call, atomic_read(&call->usage)); - return call; - - /* we found the call on the second time through the list */ -found_extant_second: - rxrpc_get_call(call); + /* We unexpectedly found the user ID in the list after taking + * the call_lock. This shouldn't happen unless the user races + * with itself and tries to add the same user ID twice at the + * same time in different threads. + */ +found_user_ID_now_present: write_unlock(&rx->call_lock); - rxrpc_put_call(candidate); - _leave(" = %p [second %d]", call, atomic_read(&call->usage)); - return call; + rxrpc_put_call(call); + _leave(" = -EEXIST [%p]", call); + return ERR_PTR(-EEXIST); } /* @@ -566,46 +572,6 @@ old_call: } /* - * find an extant server call - * - called in process context with IRQs enabled - */ -struct rxrpc_call *rxrpc_find_server_call(struct rxrpc_sock *rx, - unsigned long user_call_ID) -{ - struct rxrpc_call *call; - struct rb_node *p; - - _enter("%p,%lx", rx, user_call_ID); - - /* search the extant calls for one that matches the specified user - * ID */ - read_lock(&rx->call_lock); - - p = rx->calls.rb_node; - while (p) { - call = rb_entry(p, struct rxrpc_call, sock_node); - - if (user_call_ID < call->user_call_ID) - p = p->rb_left; - else if (user_call_ID > call->user_call_ID) - p = p->rb_right; - else - goto found_extant_call; - } - - read_unlock(&rx->call_lock); - _leave(" = NULL"); - return NULL; - - /* we found the call in the list immediately */ -found_extant_call: - rxrpc_get_call(call); - read_unlock(&rx->call_lock); - _leave(" = %p [%d]", call, atomic_read(&call->usage)); - return call; -} - -/* * detach a call from a socket and set up for release */ void rxrpc_release_call(struct rxrpc_call *call) |