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 --- fs/afs/vlclient.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'fs/afs/vlclient.c') diff --git a/fs/afs/vlclient.c b/fs/afs/vlclient.c index f94d1abdc3eb..94bcd97d22b8 100644 --- a/fs/afs/vlclient.c +++ b/fs/afs/vlclient.c @@ -58,17 +58,16 @@ static int afs_vl_abort_to_error(u32 abort_code) /* * deliver reply data to a VL.GetEntryByXXX call */ -static int afs_deliver_vl_get_entry_by_xxx(struct afs_call *call, - struct sk_buff *skb, bool last) +static int afs_deliver_vl_get_entry_by_xxx(struct afs_call *call) { struct afs_cache_vlocation *entry; __be32 *bp; u32 tmp; int loop, ret; - _enter(",,%u", last); + _enter(""); - ret = afs_transfer_reply(call, skb, last); + ret = afs_transfer_reply(call); if (ret < 0) return ret; -- cgit v1.2.3