kernel/include/linux/sunrpc/svc_xprt.h, branch linux-6.17.y

nfsd: unregister with rpcbind when deleting a transport

2025-10-19T14:37:00Z

commit 898374fdd7f06fa4c4a66e8be3135efeae6128d5 upstream. When a listener is added, a part of creation of transport also registers program/port with rpcbind. However, when the listener is removed, while transport goes away, rpcbind still has the entry for that port/type. When deleting the transport, unregister with rpcbind when appropriate. ---v2 created a new xpt_flag XPT_RPCB_UNREG to mark TCP and UDP transport and at xprt destroy send rpcbind unregister if flag set. Suggested-by: Chuck Lever Fixes: d093c9089260 ("nfsd: fix management of listener transports") Cc: stable@vger.kernel.org Signed-off-by: Olga Kornievskaia Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

sunrpc: add info about xprt queue times to svc_xprt_dequeue tracepoint

2025-05-11T23:48:26Z

I've been looking at a problem where we see increased RPC timeouts in clients when the nfs_layout_flexfiles dataserver_timeo value is tuned very low (6s). This is necessary to ensure quick failover to a different mirror if a server goes down, but it causes a lot more major RPC timeouts. Ultimately, the problem is server-side however. It's sometimes doesn't respond to connection attempts. My theory is that the interrupt handler runs when a connection comes in, the xprt ends up being enqueued, but it takes a significant amount of time for the nfsd thread to pick it up. Currently, the svc_xprt_dequeue tracepoint displays "wakeup-us". This is the time between the wake_up() call, and the thread dequeueing the xprt. If no thread was woken, or the thread ended up picking up a different xprt than intended, then this value won't tell us how long the xprt was waiting. Add a new xpt_qtime field to struct svc_xprt and set it in svc_xprt_enqueue(). When the dequeue tracepoint fires, also store the time that the xprt sat on the queue in total. Display it as "qtime-us". Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever

sunrpc: remove all connection limit configuration

2025-01-06T14:37:36Z

Now that the connection limit only apply to unconfirmed connections, there is no need to configure it. So remove all the configuration and fix the number of unconfirmed connections as always 64 - which is now given a name: XPT_MAX_TMP_CONN Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

nfsd: don't use sv_nrthreads in connection limiting calculations.

2025-01-06T14:37:36Z

The heuristic for limiting the number of incoming connections to nfsd currently uses sv_nrthreads - allowing more connections if more threads were configured. A future patch will allow number of threads to grow dynamically so that there will be no need to configure sv_nrthreads. So we need a different solution for limiting connections. It isn't clear what problem is solved by limiting connections (as mentioned in a code comment) but the most likely problem is a connection storm - many connections that are not doing productive work. These will be closed after about 6 minutes already but it might help to slow down a storm. This patch adds a per-connection flag XPT_PEER_VALID which indicates that the peer has presented a filehandle for which it has some sort of access. i.e the peer is known to be trusted in some way. We now only count connections which have NOT been determined to be valid. There should be relative few of these at any given time. If the number of non-validated peer exceed a limit - currently 64 - we close the oldest non-validated peer to avoid having too many of these useless connections. Note that this patch significantly changes the meaning of the various configuration parameters for "max connections". The next patch will remove all of these. Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

SUNRPC: add a new svc_find_listener helper

2024-05-06T13:07:22Z

svc_find_listener will return the transport instance pointer for the endpoint accepting connections/peer traffic from the specified transport class and matching sockaddr. Signed-off-by: Jeff Layton Signed-off-by: Lorenzo Bianconi Signed-off-by: Chuck Lever

SUNRPC: introduce svc_xprt_create_from_sa utility routine

2024-05-06T13:07:22Z

Add svc_xprt_create_from_sa utility routine and refactor svc_xprt_create() codebase in order to introduce the capability to create a svc port from socket address. Reviewed-by: Jeff Layton Tested-by: Jeff Layton Signed-off-by: Lorenzo Bianconi Signed-off-by: Chuck Lever

SUNRPC: use lwq for sp_sockets - renamed to sp_xprts

2023-10-16T16:44:07Z

lwq avoids using back pointers in lists, and uses less locking. This introduces a new spinlock, but the other one will be removed in a future patch. For svc_clean_up_xprts(), we now dequeue the entire queue, walk it to remove and process the xprts that need cleaning up, then re-enqueue the remaining queue. Signed-off-by: NeilBrown Signed-off-by: Chuck Lever

SUNRPC: change svc_xprt::xpt_flags bits to enum

2023-08-29T21:45:22Z

When a sequence of numbers are needed for internal-use only, an enum is typically best. The sequence will inevitably need to be changed one day, and having an enum means the developer doesn't need to think about renumbering after insertion or deletion. Such patches will be easier to review. Suggested-by: NeilBrown Signed-off-by: Chuck Lever

SUNRPC: always free ctxt when freeing deferred request

2023-05-14T19:55:02Z

Since the ->xprt_ctxt pointer was added to svc_deferred_req, it has not been sufficient to use kfree() to free a deferred request. We may need to free the ctxt as well. As freeing the ctxt is all that ->xpo_release_rqst() does, we repurpose it to explicit do that even when the ctxt is not stored in an rqst. So we now have ->xpo_release_ctxt() which is given an xprt and a ctxt, which may have been taken either from an rqst or from a dreq. The caller is now responsible for clearing that pointer after the call to ->xpo_release_ctxt. We also clear dr->xprt_ctxt when the ctxt is moved into a new rqst when revisiting a deferred request. This ensures there is only one pointer to the ctxt, so the risk of double freeing in future is reduced. The new code in svc_xprt_release which releases both the ctxt and any rq_deferred depends on this. Fixes: 773f91b2cf3f ("SUNRPC: Fix NFSD's request deferral on RDMA transports") Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

SUNRPC: Support TLS handshake in the server-side TCP socket code

2023-04-27T22:49:24Z

This patch adds opportunitistic RPC-with-TLS to the Linux in-kernel NFS server. If the client requests RPC-with-TLS and the user space handshake agent is running, the server will set up a TLS session. There are no policy settings yet. For example, the server cannot yet require the use of RPC-with-TLS to access its data. Signed-off-by: Chuck Lever