mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
synced 2026-10-30 22:03:17 +01:00
Chuck Lever
3674f780f4
A backchannel receive can complete a request while the NFS callback service is being torn down. xprt_complete_bc_request() removes the request from bc_pa_list, drops bc_alloc_count, marks the request in use, and then asks xprt_enqueue_bc_request() to hand it to the callback service. If teardown has already cleared xprt->bc_serv, xprt_enqueue_bc_request() currently returns without enqueueing or freeing the committed request. The xprt_get() taken on entry is leaked as well. If the producer wins the race before bc_serv is cleared, it can also enqueue onto sv_cb_list after nfs_callback_down() has stopped the callback threads, leaving the request linked to a svc_serv that is about to be freed. Close the producer side before callback threads are stopped. Add xprt_svc_shutdown_bc() to clear xprt->bc_serv under bc_pa_lock, and call it on callback shutdown and callback-start failure before stopping the service threads. Requests that lose the NULL transition in xprt_enqueue_bc_request() are released through the normal backchannel free path after balancing bc_slot_count. Finally, drain any remaining sv_cb_list requests after the callback threads have stopped and before svc_destroy() frees the service. Fixes:441244d427("SUNRPC: cleanup common code in backchannel request") Fixes:9e9fdd0ad0("NFSv4.1: protect destroying and nullifying bc_serv structure") Cc: [email protected] Signed-off-by: Chris Mason <[email protected]> Reviewed-by: Jeff Layton <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Chuck Lever <[email protected]>
85 lines
2.3 KiB
C
85 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/******************************************************************************
|
|
|
|
(c) 2008 NetApp. All Rights Reserved.
|
|
|
|
|
|
******************************************************************************/
|
|
|
|
/*
|
|
* Functions to create and manage the backchannel
|
|
*/
|
|
|
|
#ifndef _LINUX_SUNRPC_BC_XPRT_H
|
|
#define _LINUX_SUNRPC_BC_XPRT_H
|
|
|
|
#include <linux/sunrpc/svcsock.h>
|
|
#include <linux/sunrpc/xprt.h>
|
|
#include <linux/sunrpc/sched.h>
|
|
|
|
#ifdef CONFIG_SUNRPC_BACKCHANNEL
|
|
struct rpc_rqst *xprt_lookup_bc_request(struct rpc_xprt *xprt, __be32 xid);
|
|
void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied);
|
|
void xprt_init_bc_request(struct rpc_rqst *req, struct rpc_task *task,
|
|
const struct rpc_timeout *to);
|
|
void xprt_free_bc_request(struct rpc_rqst *req);
|
|
int xprt_setup_backchannel(struct rpc_xprt *, unsigned int min_reqs);
|
|
void xprt_destroy_backchannel(struct rpc_xprt *, unsigned int max_reqs);
|
|
void xprt_enqueue_bc_request(struct rpc_rqst *req);
|
|
|
|
/* Socket backchannel transport methods */
|
|
int xprt_setup_bc(struct rpc_xprt *xprt, unsigned int min_reqs);
|
|
void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs);
|
|
void xprt_free_bc_rqst(struct rpc_rqst *req);
|
|
unsigned int xprt_bc_max_slots(struct rpc_xprt *xprt);
|
|
void xprt_svc_shutdown_bc(struct rpc_xprt *xprt);
|
|
void xprt_svc_destroy_nullify_bc(struct rpc_xprt *xprt, struct svc_serv **serv);
|
|
|
|
/*
|
|
* Determine if a shared backchannel is in use
|
|
*/
|
|
static inline bool svc_is_backchannel(const struct svc_rqst *rqstp)
|
|
{
|
|
return rqstp->rq_server->sv_bc_enabled;
|
|
}
|
|
|
|
static inline void set_bc_enabled(struct svc_serv *serv)
|
|
{
|
|
serv->sv_bc_enabled = true;
|
|
}
|
|
#else /* CONFIG_SUNRPC_BACKCHANNEL */
|
|
static inline int xprt_setup_backchannel(struct rpc_xprt *xprt,
|
|
unsigned int min_reqs)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void xprt_destroy_backchannel(struct rpc_xprt *xprt,
|
|
unsigned int max_reqs)
|
|
{
|
|
}
|
|
|
|
static inline bool svc_is_backchannel(const struct svc_rqst *rqstp)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline void set_bc_enabled(struct svc_serv *serv)
|
|
{
|
|
}
|
|
|
|
static inline void xprt_free_bc_request(struct rpc_rqst *req)
|
|
{
|
|
}
|
|
|
|
static inline void xprt_svc_shutdown_bc(struct rpc_xprt *xprt)
|
|
{
|
|
}
|
|
|
|
static inline void xprt_svc_destroy_nullify_bc(struct rpc_xprt *xprt, struct svc_serv **serv)
|
|
{
|
|
svc_destroy(serv);
|
|
}
|
|
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
|
|
#endif /* _LINUX_SUNRPC_BC_XPRT_H */
|