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linux-stable-mirror/include/linux/sunrpc/svc_rdma.h
T
Chuck LeverandChuck Lever e5248a7426 svcrdma: wake sq waiters when the transport closes 
Threads parked in svc_rdma_sq_wait() on sc_sq_ticket_wait or
sc_send_wait can hang indefinitely in TASK_UNINTERRUPTIBLE state
across transport teardown, pinning svc_xprt references and
blocking svc_rdma_free().

The close path sets XPT_CLOSE before invoking xpo_detach and both
wait_event predicates include an XPT_CLOSE term, but the
predicates are re-evaluated only on wakeup. sc_sq_ticket_wait has
no completion-driven wake path; it is advanced solely by the
chained ticket handoff inside svc_rdma_sq_wait() itself. Without
an explicit wake at close, parked threads never observe
XPT_CLOSE, hold their svc_xprt_get reference forever, and
svc_rdma_free() blocks on xpt_ref dropping to zero.

Two close entry points reach this transport. Local teardown runs
svc_rdma_detach() from svc_handle_xprt() -> svc_delete_xprt() ->
xpo_detach() on a worker thread. A remote disconnect arrives at
svc_rdma_cma_handler(), which calls svc_xprt_deferred_close():
that sets XPT_CLOSE and enqueues the transport but does not
access either RDMA waitqueue, so a worker already parked in
svc_rdma_sq_wait() never re-evaluates its predicate. With every
worker parked on this transport, no thread is available to run
the local teardown either, and the wake site there is
unreachable.

Introduce svc_rdma_xprt_deferred_close(), a thin svcrdma wrapper
that calls svc_xprt_deferred_close() and then wakes both
sc_sq_ticket_wait and sc_send_wait. Convert the svcrdma producers
that called svc_xprt_deferred_close() directly:
svc_rdma_cma_handler(), qp_event_handler(),
svc_rdma_post_send_err(), svc_rdma_wc_send(), the sendto drop
path, the rw completion error paths, and the recvfrom flush and
read-list error paths.

Wake both waitqueues from svc_rdma_detach() as well. The
synchronous svc_xprt_close() path (backchannel ENOTCONN, device
removal via svc_rdma_xprt_done) reaches detach without flowing
through svc_xprt_deferred_close() and therefore does not invoke
the new helper.

Fixes: ccc89b9d1e ("svcrdma: Add fair queuing for Send Queue access")
Cc: stable@vger.kernel.org
Assisted-by: kres (claude-opus-4-7)
Signed-off-by: Chris Mason <clm@meta.com>
[ cel: add svc_rdma_xprt_deferred_close() to complete the fix ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2026-06-09 16:32:59 -04:00

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/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
/*
* Copyright (c) 2005-2006 Network Appliance, Inc. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the BSD-type
* license below:
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of the Network Appliance, Inc. nor the names of
* its contributors may be used to endorse or promote products
* derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Author: Tom Tucker <tom@opengridcomputing.com>
*/
#ifndef SVC_RDMA_H
#define SVC_RDMA_H
#include <linux/llist.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/sunrpc/rpc_rdma_cid.h>
#include <linux/sunrpc/svc_rdma_pcl.h>
#include <linux/sunrpc/rdma_rn.h>
#include <linux/percpu_counter.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
/* Default and maximum inline threshold sizes */
enum {
RPCRDMA_PULLUP_THRESH = RPCRDMA_V1_DEF_INLINE_SIZE >> 1,
RPCRDMA_DEF_INLINE_THRESH = 4096,
RPCRDMA_MAX_INLINE_THRESH = 65536
};
/* RPC/RDMA parameters and stats */
extern unsigned int svcrdma_ord;
extern unsigned int svcrdma_max_requests;
extern unsigned int svcrdma_max_bc_requests;
extern unsigned int svcrdma_max_req_size;
extern struct percpu_counter svcrdma_stat_read;
extern struct percpu_counter svcrdma_stat_recv;
extern struct percpu_counter svcrdma_stat_sq_starve;
extern struct percpu_counter svcrdma_stat_write;
struct svcxprt_rdma {
struct svc_xprt sc_xprt; /* SVC transport structure */
struct rdma_cm_id *sc_cm_id; /* RDMA connection id */
struct list_head sc_accept_q; /* Conn. waiting accept */
struct rpcrdma_notification sc_rn; /* removal notification */
int sc_ord; /* RDMA read limit */
int sc_max_send_sges;
bool sc_snd_w_inv; /* OK to use Send With Invalidate */
atomic_t sc_sq_avail; /* SQEs ready to be consumed */
unsigned int sc_sq_depth; /* Depth of SQ */
atomic_t sc_sq_ticket_head; /* Next ticket to issue */
atomic_t sc_sq_ticket_tail; /* Ticket currently serving */
wait_queue_head_t sc_sq_ticket_wait; /* Ticket ordering waitlist */
__be32 sc_fc_credits; /* Forward credits */
u32 sc_max_requests; /* Max requests */
u32 sc_max_bc_requests;/* Backward credits */
int sc_max_req_size; /* Size of each RQ WR buf */
u8 sc_port_num;
struct ib_pd *sc_pd;
spinlock_t sc_send_lock;
struct llist_head sc_send_ctxts;
spinlock_t sc_rw_ctxt_lock;
struct llist_head sc_rw_ctxts;
u32 sc_pending_recvs;
u32 sc_recv_batch;
struct list_head sc_rq_dto_q;
struct list_head sc_read_complete_q;
spinlock_t sc_rq_dto_lock;
struct ib_qp *sc_qp;
struct ib_cq *sc_rq_cq;
struct ib_cq *sc_sq_cq;
spinlock_t sc_lock; /* transport lock */
wait_queue_head_t sc_send_wait; /* SQ exhaustion waitlist */
unsigned long sc_flags;
struct work_struct sc_work;
struct llist_head sc_recv_ctxts;
struct llist_head sc_send_release_list;
atomic_t sc_completion_ids;
};
/* sc_flags */
#define RDMAXPRT_CONN_PENDING 3
static inline struct svcxprt_rdma *svc_rdma_rqst_rdma(struct svc_rqst *rqstp)
{
struct svc_xprt *xprt = rqstp->rq_xprt;
return container_of(xprt, struct svcxprt_rdma, sc_xprt);
}
/*
* Default connection parameters
*/
enum {
RPCRDMA_LISTEN_BACKLOG = 10,
RPCRDMA_MAX_REQUESTS = 128,
RPCRDMA_MAX_BC_REQUESTS = 2,
};
#define RPCSVC_MAXPAYLOAD_RDMA RPCSVC_MAXPAYLOAD
/**
* svc_rdma_send_cid_init - Initialize a Receive Queue completion ID
* @rdma: controlling transport
* @cid: completion ID to initialize
*/
static inline void svc_rdma_recv_cid_init(struct svcxprt_rdma *rdma,
struct rpc_rdma_cid *cid)
{
cid->ci_queue_id = rdma->sc_rq_cq->res.id;
cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids);
}
/**
* svc_rdma_send_cid_init - Initialize a Send Queue completion ID
* @rdma: controlling transport
* @cid: completion ID to initialize
*/
static inline void svc_rdma_send_cid_init(struct svcxprt_rdma *rdma,
struct rpc_rdma_cid *cid)
{
cid->ci_queue_id = rdma->sc_sq_cq->res.id;
cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids);
}
/*
* A chunk context tracks all I/O for moving one Read or Write
* chunk. This is a set of rdma_rw's that handle data movement
* for all segments of one chunk.
*/
struct svc_rdma_chunk_ctxt {
struct rpc_rdma_cid cc_cid;
struct ib_cqe cc_cqe;
struct list_head cc_rwctxts;
ktime_t cc_posttime;
int cc_sqecount;
};
struct svc_rdma_recv_ctxt {
struct llist_node rc_node;
struct list_head rc_list;
struct ib_recv_wr rc_recv_wr;
struct ib_cqe rc_cqe;
struct rpc_rdma_cid rc_cid;
struct ib_sge rc_recv_sge;
void *rc_recv_buf;
struct xdr_stream rc_stream;
u32 rc_byte_len;
u32 rc_inv_rkey;
__be32 rc_msgtype;
/* State for pulling a Read chunk */
unsigned int rc_pageoff;
unsigned int rc_curpage;
unsigned int rc_readbytes;
struct xdr_buf rc_saved_arg;
struct svc_rdma_chunk_ctxt rc_cc;
struct svc_rdma_pcl rc_call_pcl;
struct svc_rdma_pcl rc_read_pcl;
struct svc_rdma_chunk *rc_cur_result_payload;
struct svc_rdma_pcl rc_write_pcl;
struct svc_rdma_pcl rc_reply_pcl;
unsigned int rc_page_count;
unsigned long rc_maxpages;
struct page *rc_pages[] __counted_by(rc_maxpages);
};
/*
* State for sending a Write chunk.
* - Tracks progress of writing one chunk over all its segments
* - Stores arguments for the SGL constructor functions
*/
struct svc_rdma_write_info {
struct svcxprt_rdma *wi_rdma;
struct list_head wi_list;
const struct svc_rdma_chunk *wi_chunk;
/* write state of this chunk */
unsigned int wi_seg_off;
unsigned int wi_seg_no;
/* SGL constructor arguments */
const struct xdr_buf *wi_xdr;
unsigned char *wi_base;
unsigned int wi_next_off;
struct svc_rdma_chunk_ctxt wi_cc;
};
struct svc_rdma_send_ctxt {
struct llist_node sc_node;
struct rpc_rdma_cid sc_cid;
struct svcxprt_rdma *sc_rdma;
struct ib_send_wr sc_send_wr;
struct ib_send_wr *sc_wr_chain;
int sc_sqecount;
struct ib_cqe sc_cqe;
struct xdr_buf sc_hdrbuf;
struct xdr_stream sc_stream;
struct list_head sc_write_info_list;
struct svc_rdma_write_info sc_reply_info;
void *sc_xprt_buf;
int sc_page_count;
int sc_cur_sge_no;
unsigned long sc_maxpages;
struct page **sc_pages;
struct ib_sge sc_sges[];
};
/* svc_rdma_backchannel.c */
extern void svc_rdma_handle_bc_reply(struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *rctxt);
/* svc_rdma_recvfrom.c */
extern void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma);
extern bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma);
extern struct svc_rdma_recv_ctxt *
svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma);
extern void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma,
struct svc_rdma_recv_ctxt *ctxt);
extern void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma);
extern void svc_rdma_release_ctxt(struct svc_xprt *xprt, void *ctxt);
extern int svc_rdma_recvfrom(struct svc_rqst *);
/* svc_rdma_rw.c */
extern void svc_rdma_cc_init(struct svcxprt_rdma *rdma,
struct svc_rdma_chunk_ctxt *cc);
extern void svc_rdma_destroy_rw_ctxts(struct svcxprt_rdma *rdma);
extern void svc_rdma_cc_init(struct svcxprt_rdma *rdma,
struct svc_rdma_chunk_ctxt *cc);
extern void svc_rdma_cc_release(struct svcxprt_rdma *rdma,
struct svc_rdma_chunk_ctxt *cc,
enum dma_data_direction dir);
extern void svc_rdma_write_chunk_release(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt);
extern void svc_rdma_reply_chunk_release(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt);
extern int svc_rdma_prepare_write_list(struct svcxprt_rdma *rdma,
const struct svc_rdma_recv_ctxt *rctxt,
struct svc_rdma_send_ctxt *sctxt,
const struct xdr_buf *xdr);
extern int svc_rdma_prepare_reply_chunk(struct svcxprt_rdma *rdma,
const struct svc_rdma_pcl *write_pcl,
const struct svc_rdma_pcl *reply_pcl,
struct svc_rdma_send_ctxt *sctxt,
const struct xdr_buf *xdr);
extern int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *head);
/* svc_rdma_sendto.c */
extern void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma);
extern void svc_rdma_send_ctxts_drain(struct svcxprt_rdma *rdma);
extern struct svc_rdma_send_ctxt *
svc_rdma_send_ctxt_get(struct svcxprt_rdma *rdma);
extern void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt);
extern int svc_rdma_post_send(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt);
extern int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *sctxt,
const struct svc_rdma_pcl *write_pcl,
const struct svc_rdma_pcl *reply_pcl,
const struct xdr_buf *xdr);
extern void svc_rdma_send_error_msg(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *sctxt,
struct svc_rdma_recv_ctxt *rctxt,
int status);
extern void svc_rdma_wake_send_waiters(struct svcxprt_rdma *rdma, int avail);
extern int svc_rdma_sq_wait(struct svcxprt_rdma *rdma,
const struct rpc_rdma_cid *cid, int sqecount);
extern int svc_rdma_post_send_err(struct svcxprt_rdma *rdma,
const struct rpc_rdma_cid *cid,
const struct ib_send_wr *bad_wr,
const struct ib_send_wr *first_wr,
int sqecount, int ret);
extern int svc_rdma_sendto(struct svc_rqst *);
extern int svc_rdma_result_payload(struct svc_rqst *rqstp, unsigned int offset,
unsigned int length);
/* svc_rdma_transport.c */
extern void svc_rdma_xprt_deferred_close(struct svcxprt_rdma *rdma);
extern struct svc_xprt_class svc_rdma_class;
#ifdef CONFIG_SUNRPC_BACKCHANNEL
extern struct svc_xprt_class svc_rdma_bc_class;
#endif
/* svc_rdma.c */
extern int svc_rdma_init(void);
extern void svc_rdma_cleanup(void);
#endif
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