From d001648ec7cf8b21ae9eec8b9ba4a18295adfb14 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 30 Aug 2016 20:42:14 +0100 Subject: rxrpc: Don't expose skbs to in-kernel users [ver #2] Don't expose skbs to in-kernel users, such as the AFS filesystem, but instead provide a notification hook the indicates that a call needs attention and another that indicates that there's a new call to be collected. This makes the following possibilities more achievable: (1) Call refcounting can be made simpler if skbs don't hold refs to calls. (2) skbs referring to non-data events will be able to be freed much sooner rather than being queued for AFS to pick up as rxrpc_kernel_recv_data will be able to consult the call state. (3) We can shortcut the receive phase when a call is remotely aborted because we don't have to go through all the packets to get to the one cancelling the operation. (4) It makes it easier to do encryption/decryption directly between AFS's buffers and sk_buffs. (5) Encryption/decryption can more easily be done in the AFS's thread contexts - usually that of the userspace process that issued a syscall - rather than in one of rxrpc's background threads on a workqueue. (6) AFS will be able to wait synchronously on a call inside AF_RXRPC. To make this work, the following interface function has been added: int rxrpc_kernel_recv_data( struct socket *sock, struct rxrpc_call *call, void *buffer, size_t bufsize, size_t *_offset, bool want_more, u32 *_abort_code); This is the recvmsg equivalent. It allows the caller to find out about the state of a specific call and to transfer received data into a buffer piecemeal. afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction logic between them. They don't wait synchronously yet because the socket lock needs to be dealt with. Five interface functions have been removed: rxrpc_kernel_is_data_last() rxrpc_kernel_get_abort_code() rxrpc_kernel_get_error_number() rxrpc_kernel_free_skb() rxrpc_kernel_data_consumed() As a temporary hack, sk_buffs going to an in-kernel call are queued on the rxrpc_call struct (->knlrecv_queue) rather than being handed over to the in-kernel user. To process the queue internally, a temporary function, temp_deliver_data() has been added. This will be replaced with common code between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a future patch. Signed-off-by: David Howells Signed-off-by: David S. Miller --- net/rxrpc/output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/rxrpc/output.c') diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c index b1e708a12151..817ae801e769 100644 --- a/net/rxrpc/output.c +++ b/net/rxrpc/output.c @@ -190,7 +190,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) if (cmd == RXRPC_CMD_ACCEPT) { if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) return -EINVAL; - call = rxrpc_accept_call(rx, user_call_ID); + call = rxrpc_accept_call(rx, user_call_ID, NULL); if (IS_ERR(call)) return PTR_ERR(call); rxrpc_put_call(call); -- cgit v1.2.3-59-g8ed1b