From 7402a4fedc2bc448100c2d086406c708451b16dc Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 16 Jul 2019 13:51:29 -0400 Subject: [PATCH] SUNRPC: Fix up backchannel slot table accounting Add a per-transport maximum limit in the socket case, and add helpers to allow the NFSv4 code to discover that limit. Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 3 +++ include/linux/sunrpc/bc_xprt.h | 1 + include/linux/sunrpc/clnt.h | 1 + include/linux/sunrpc/xprt.h | 6 +++-- net/sunrpc/backchannel_rqst.c | 40 +++++++++++++++++-------------- net/sunrpc/clnt.c | 13 ++++++++++ net/sunrpc/svc.c | 2 +- net/sunrpc/xprtrdma/backchannel.c | 7 ++++++ net/sunrpc/xprtrdma/transport.c | 1 + net/sunrpc/xprtrdma/xprt_rdma.h | 1 + net/sunrpc/xprtsock.c | 1 + 11 files changed, 55 insertions(+), 21 deletions(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 52de7245a2ee..39896afc6edf 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -8380,6 +8380,7 @@ static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args, { unsigned int max_rqst_sz, max_resp_sz; unsigned int max_bc_payload = rpc_max_bc_payload(clnt); + unsigned int max_bc_slots = rpc_num_bc_slots(clnt); max_rqst_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxwrite_overhead; max_resp_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxread_overhead; @@ -8402,6 +8403,8 @@ static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args, args->bc_attrs.max_resp_sz_cached = 0; args->bc_attrs.max_ops = NFS4_MAX_BACK_CHANNEL_OPS; args->bc_attrs.max_reqs = max_t(unsigned short, max_session_cb_slots, 1); + if (args->bc_attrs.max_reqs > max_bc_slots) + args->bc_attrs.max_reqs = max_bc_slots; dprintk("%s: Back Channel : max_rqst_sz=%u max_resp_sz=%u " "max_resp_sz_cached=%u max_ops=%u max_reqs=%u\n", diff --git a/include/linux/sunrpc/bc_xprt.h b/include/linux/sunrpc/bc_xprt.h index d4229a78524a..87d27e13d885 100644 --- a/include/linux/sunrpc/bc_xprt.h +++ b/include/linux/sunrpc/bc_xprt.h @@ -43,6 +43,7 @@ void xprt_destroy_backchannel(struct rpc_xprt *, unsigned int max_reqs); 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); /* * Determine if a shared backchannel is in use diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h index 4e070e00c143..abc63bd1be2b 100644 --- a/include/linux/sunrpc/clnt.h +++ b/include/linux/sunrpc/clnt.h @@ -194,6 +194,7 @@ void rpc_setbufsize(struct rpc_clnt *, unsigned int, unsigned int); struct net * rpc_net_ns(struct rpc_clnt *); size_t rpc_max_payload(struct rpc_clnt *); size_t rpc_max_bc_payload(struct rpc_clnt *); +unsigned int rpc_num_bc_slots(struct rpc_clnt *); void rpc_force_rebind(struct rpc_clnt *); size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t); const char *rpc_peeraddr2str(struct rpc_clnt *, enum rpc_display_format_t); diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index ed76e5fb36c1..13e108bcc9eb 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -158,6 +158,7 @@ struct rpc_xprt_ops { int (*bc_setup)(struct rpc_xprt *xprt, unsigned int min_reqs); size_t (*bc_maxpayload)(struct rpc_xprt *xprt); + unsigned int (*bc_num_slots)(struct rpc_xprt *xprt); void (*bc_free_rqst)(struct rpc_rqst *rqst); void (*bc_destroy)(struct rpc_xprt *xprt, unsigned int max_reqs); @@ -251,8 +252,9 @@ struct rpc_xprt { #if defined(CONFIG_SUNRPC_BACKCHANNEL) struct svc_serv *bc_serv; /* The RPC service which will */ /* process the callback */ - int bc_alloc_count; /* Total number of preallocs */ - atomic_t bc_free_slots; + unsigned int bc_alloc_max; + unsigned int bc_alloc_count; /* Total number of preallocs */ + atomic_t bc_slot_count; /* Number of allocated slots */ spinlock_t bc_pa_lock; /* Protects the preallocated * items */ struct list_head bc_pa_list; /* List of preallocated diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c index c47d82622fd1..339e8c077c2d 100644 --- a/net/sunrpc/backchannel_rqst.c +++ b/net/sunrpc/backchannel_rqst.c @@ -31,25 +31,20 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #define RPCDBG_FACILITY RPCDBG_TRANS #endif +#define BC_MAX_SLOTS 64U + +unsigned int xprt_bc_max_slots(struct rpc_xprt *xprt) +{ + return BC_MAX_SLOTS; +} + /* * Helper routines that track the number of preallocation elements * on the transport. */ static inline int xprt_need_to_requeue(struct rpc_xprt *xprt) { - return xprt->bc_alloc_count < atomic_read(&xprt->bc_free_slots); -} - -static inline void xprt_inc_alloc_count(struct rpc_xprt *xprt, unsigned int n) -{ - atomic_add(n, &xprt->bc_free_slots); - xprt->bc_alloc_count += n; -} - -static inline int xprt_dec_alloc_count(struct rpc_xprt *xprt, unsigned int n) -{ - atomic_sub(n, &xprt->bc_free_slots); - return xprt->bc_alloc_count -= n; + return xprt->bc_alloc_count < xprt->bc_alloc_max; } /* @@ -145,6 +140,9 @@ int xprt_setup_bc(struct rpc_xprt *xprt, unsigned int min_reqs) dprintk("RPC: setup backchannel transport\n"); + if (min_reqs > BC_MAX_SLOTS) + min_reqs = BC_MAX_SLOTS; + /* * We use a temporary list to keep track of the preallocated * buffers. Once we're done building the list we splice it @@ -172,7 +170,9 @@ int xprt_setup_bc(struct rpc_xprt *xprt, unsigned int min_reqs) */ spin_lock(&xprt->bc_pa_lock); list_splice(&tmp_list, &xprt->bc_pa_list); - xprt_inc_alloc_count(xprt, min_reqs); + xprt->bc_alloc_count += min_reqs; + xprt->bc_alloc_max += min_reqs; + atomic_add(min_reqs, &xprt->bc_slot_count); spin_unlock(&xprt->bc_pa_lock); dprintk("RPC: setup backchannel transport done\n"); @@ -220,11 +220,13 @@ void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs) goto out; spin_lock_bh(&xprt->bc_pa_lock); - xprt_dec_alloc_count(xprt, max_reqs); + xprt->bc_alloc_max -= max_reqs; list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) { dprintk("RPC: req=%p\n", req); list_del(&req->rq_bc_pa_list); xprt_free_allocation(req); + xprt->bc_alloc_count--; + atomic_dec(&xprt->bc_slot_count); if (--max_reqs == 0) break; } @@ -241,13 +243,14 @@ static struct rpc_rqst *xprt_get_bc_request(struct rpc_xprt *xprt, __be32 xid, struct rpc_rqst *req = NULL; dprintk("RPC: allocate a backchannel request\n"); - if (atomic_read(&xprt->bc_free_slots) <= 0) - goto not_found; if (list_empty(&xprt->bc_pa_list)) { if (!new) goto not_found; + if (atomic_read(&xprt->bc_slot_count) >= BC_MAX_SLOTS) + goto not_found; list_add_tail(&new->rq_bc_pa_list, &xprt->bc_pa_list); xprt->bc_alloc_count++; + atomic_inc(&xprt->bc_slot_count); } req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst, rq_bc_pa_list); @@ -291,6 +294,7 @@ void xprt_free_bc_rqst(struct rpc_rqst *req) if (xprt_need_to_requeue(xprt)) { list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list); xprt->bc_alloc_count++; + atomic_inc(&xprt->bc_slot_count); req = NULL; } spin_unlock_bh(&xprt->bc_pa_lock); @@ -357,7 +361,7 @@ void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied) spin_lock(&xprt->bc_pa_lock); list_del(&req->rq_bc_pa_list); - xprt_dec_alloc_count(xprt, 1); + xprt->bc_alloc_count--; spin_unlock(&xprt->bc_pa_lock); req->rq_private_buf.len = copied; diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 383555d2b522..79c849391cb9 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -1526,6 +1526,19 @@ size_t rpc_max_bc_payload(struct rpc_clnt *clnt) } EXPORT_SYMBOL_GPL(rpc_max_bc_payload); +unsigned int rpc_num_bc_slots(struct rpc_clnt *clnt) +{ + struct rpc_xprt *xprt; + unsigned int ret; + + rcu_read_lock(); + xprt = rcu_dereference(clnt->cl_xprt); + ret = xprt->ops->bc_num_slots(xprt); + rcu_read_unlock(); + return ret; +} +EXPORT_SYMBOL_GPL(rpc_num_bc_slots); + /** * rpc_force_rebind - force transport to check that remote port is unchanged * @clnt: client to rebind diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index e15cb704453e..220b79988000 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -1595,7 +1595,7 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req, /* Parse and execute the bc call */ proc_error = svc_process_common(rqstp, argv, resv); - atomic_inc(&req->rq_xprt->bc_free_slots); + atomic_dec(&req->rq_xprt->bc_slot_count); if (!proc_error) { /* Processing error: drop the request */ xprt_free_bc_request(req); diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c index ce986591f213..59e624b1d7a0 100644 --- a/net/sunrpc/xprtrdma/backchannel.c +++ b/net/sunrpc/xprtrdma/backchannel.c @@ -52,6 +52,13 @@ size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *xprt) return maxmsg - RPCRDMA_HDRLEN_MIN; } +unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *xprt) +{ + struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt); + + return r_xprt->rx_buf.rb_bc_srv_max_requests; +} + static int rpcrdma_bc_marshal_reply(struct rpc_rqst *rqst) { struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt); diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index 4993aa49ecbe..52abddac19e5 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -812,6 +812,7 @@ static const struct rpc_xprt_ops xprt_rdma_procs = { #if defined(CONFIG_SUNRPC_BACKCHANNEL) .bc_setup = xprt_rdma_bc_setup, .bc_maxpayload = xprt_rdma_bc_maxpayload, + .bc_num_slots = xprt_rdma_bc_max_slots, .bc_free_rqst = xprt_rdma_bc_free_rqst, .bc_destroy = xprt_rdma_bc_destroy, #endif diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 8378f45d2da7..92ce09fcea74 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -605,6 +605,7 @@ void xprt_rdma_cleanup(void); #if defined(CONFIG_SUNRPC_BACKCHANNEL) int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int); size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *); +unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *); int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int); void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *); int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst); diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 3c2cc96afcaa..6b1fca51028a 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -2788,6 +2788,7 @@ static const struct rpc_xprt_ops xs_tcp_ops = { #ifdef CONFIG_SUNRPC_BACKCHANNEL .bc_setup = xprt_setup_bc, .bc_maxpayload = xs_tcp_bc_maxpayload, + .bc_num_slots = xprt_bc_max_slots, .bc_free_rqst = xprt_free_bc_rqst, .bc_destroy = xprt_destroy_bc, #endif