From 4866073e6ddf03066c925d3237903d7f4ca68982 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 16 Aug 2019 17:49:38 -0400 Subject: [PATCH] svcrdma: Use llist for managing cache of recv_ctxts Use a wait-free mechanism for managing the svc_rdma_recv_ctxts free list. Subsequently, sc_recv_lock can be eliminated. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/svc_rdma.h | 5 +++-- net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 24 ++++++++++-------------- net/sunrpc/xprtrdma/svc_rdma_transport.c | 3 +-- 3 files changed, 14 insertions(+), 18 deletions(-) diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h index edb39900fe04..40f65888dd38 100644 --- a/include/linux/sunrpc/svc_rdma.h +++ b/include/linux/sunrpc/svc_rdma.h @@ -42,6 +42,7 @@ #ifndef SVC_RDMA_H #define SVC_RDMA_H +#include #include #include #include @@ -107,8 +108,7 @@ struct svcxprt_rdma { struct list_head sc_read_complete_q; struct work_struct sc_work; - spinlock_t sc_recv_lock; - struct list_head sc_recv_ctxts; + struct llist_head sc_recv_ctxts; }; /* sc_flags */ #define RDMAXPRT_CONN_PENDING 3 @@ -125,6 +125,7 @@ enum { #define RPCSVC_MAXPAYLOAD_RDMA RPCSVC_MAXPAYLOAD 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; diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index 65e2fb9aac65..96bccd398469 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -172,9 +172,10 @@ static void svc_rdma_recv_ctxt_destroy(struct svcxprt_rdma *rdma, void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma) { struct svc_rdma_recv_ctxt *ctxt; + struct llist_node *node; - while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_recv_ctxts))) { - list_del(&ctxt->rc_list); + while ((node = llist_del_first(&rdma->sc_recv_ctxts))) { + ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node); svc_rdma_recv_ctxt_destroy(rdma, ctxt); } } @@ -183,21 +184,18 @@ static struct svc_rdma_recv_ctxt * svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma) { struct svc_rdma_recv_ctxt *ctxt; + struct llist_node *node; - spin_lock(&rdma->sc_recv_lock); - ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_recv_ctxts); - if (!ctxt) + node = llist_del_first(&rdma->sc_recv_ctxts); + if (!node) goto out_empty; - list_del(&ctxt->rc_list); - spin_unlock(&rdma->sc_recv_lock); + ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node); out: ctxt->rc_page_count = 0; return ctxt; out_empty: - spin_unlock(&rdma->sc_recv_lock); - ctxt = svc_rdma_recv_ctxt_alloc(rdma); if (!ctxt) return NULL; @@ -218,11 +216,9 @@ void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma, for (i = 0; i < ctxt->rc_page_count; i++) put_page(ctxt->rc_pages[i]); - if (!ctxt->rc_temp) { - spin_lock(&rdma->sc_recv_lock); - list_add(&ctxt->rc_list, &rdma->sc_recv_ctxts); - spin_unlock(&rdma->sc_recv_lock); - } else + if (!ctxt->rc_temp) + llist_add(&ctxt->rc_node, &rdma->sc_recv_ctxts); + else svc_rdma_recv_ctxt_destroy(rdma, ctxt); } diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c index 18d6eb3686e7..4182d569b5cf 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c @@ -140,14 +140,13 @@ static struct svcxprt_rdma *svc_rdma_create_xprt(struct svc_serv *serv, INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q); INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q); INIT_LIST_HEAD(&cma_xprt->sc_send_ctxts); - INIT_LIST_HEAD(&cma_xprt->sc_recv_ctxts); + init_llist_head(&cma_xprt->sc_recv_ctxts); INIT_LIST_HEAD(&cma_xprt->sc_rw_ctxts); init_waitqueue_head(&cma_xprt->sc_send_wait); spin_lock_init(&cma_xprt->sc_lock); spin_lock_init(&cma_xprt->sc_rq_dto_lock); spin_lock_init(&cma_xprt->sc_send_lock); - spin_lock_init(&cma_xprt->sc_recv_lock); spin_lock_init(&cma_xprt->sc_rw_ctxt_lock); /*