From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2ABE8C388F9 for ; Tue, 27 Oct 2020 07:34:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF19D21D24 for ; Tue, 27 Oct 2020 07:34:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cloud.ionos.com header.i=@cloud.ionos.com header.b="UZOXxG3b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2507708AbgJ0Hd7 (ORCPT ); Tue, 27 Oct 2020 03:33:59 -0400 Received: from mail-ed1-f66.google.com ([209.85.208.66]:33072 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729528AbgJ0Hd7 (ORCPT ); Tue, 27 Oct 2020 03:33:59 -0400 Received: by mail-ed1-f66.google.com with SMTP id w23so394119edl.0 for ; Tue, 27 Oct 2020 00:33:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloud.ionos.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=66vHYoqa6whG3krPCX3D1qlK8K0wfzKnD+NhnstScx4=; b=UZOXxG3bGkBnD4zUM9ftQaqXBZD6Ucwwz0WqPGWeeWRwT6D1h5CNWiwzjY1BIZ6ZGO F+MSFrj/YMoo/xKicz3tYnaGe6yiGyfCS+eKhYbAWmwJp74sChijjKLa8Zq66JWRlQTg es9tjx0s5c36vfLv9PagXlsxaBaUuMK81il0oScnIuJd0nt5Jx7jlynafJWA0nsvIzAa 2PptitjzFoKIYSYZ89cxz4yiQNURKkcs80teeD7S7KonGhos1I4tusCH0tsHm/En03IZ oPPnOmnsjNuVov9nkdFPnEOcrAHSOcKtU8/NJpLQoldSZHDpWXJPpO+o0L8baCotUh+b a5IQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=66vHYoqa6whG3krPCX3D1qlK8K0wfzKnD+NhnstScx4=; b=riHetXlvswb15hjnvVNJUEeQ/nFIGfbwPBNclKP535ArIiGBpnB6QTVUA6aho4Iitb ZGXWsqi9wRiFxjp4uC6UPe5jYH2AeO4+YxtGNGrF1mBFk8O3EcDBSligag/5YKv53HJo RK5N+pzYFISo2YqwmU95DHw6fIRzwOCqlXU100Xp+1kCTNfUg9e535Y+OPO/hB49HZWz 0KBvQlpwXBxUaG6EHcaBXOZCdRb7fBk8MByfhOB0/vdBCxD1lL9LI/pjQEOv38cKFluf VF620oYsOo6ywSFbKb1Y7TT8A2li03VU7OsLuYJT3/pJqk4c/JeYikQgZ143KjGgv97h qjXQ== X-Gm-Message-State: AOAM5332E0gKMdr8c3I1woc3COuPRcDYrnELsXLsEqCUUlc9368rd1wm LYl7Hk5amrpy6+5vfyYBAjFKFT/sum76Qym/JaUDSg== X-Google-Smtp-Source: ABdhPJwovVYMOgNA6lm9ValuONtBFeUvdbi0QJpCmUz1VYt5VbCBXmATuHDW5H8plOfkX7+mj2n5DJcOXdjPz0g8ESI= X-Received: by 2002:a50:e40c:: with SMTP id d12mr835831edm.35.1603784036319; Tue, 27 Oct 2020 00:33:56 -0700 (PDT) MIME-Version: 1.0 References: <0-v1-75e124dbad74+b05-rdma_connect_locking_jgg@nvidia.com> In-Reply-To: <0-v1-75e124dbad74+b05-rdma_connect_locking_jgg@nvidia.com> From: Jinpu Wang Date: Tue, 27 Oct 2020 08:33:45 +0100 Message-ID: Subject: Re: [PATCH] RDMA: Add rdma_connect_locked() To: Jason Gunthorpe Cc: Danil Kipnis , Doug Ledford , Christoph Hellwig , Keith Busch , linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org, Max Gurtovoy , netdev , rds-devel@oss.oracle.com, Sagi Grimberg , Santosh Shilimkar , Guoqing Jiang , Leon Romanovsky Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Mon, Oct 26, 2020 at 3:25 PM Jason Gunthorpe wrote: > > There are two flows for handling RDMA_CM_EVENT_ROUTE_RESOLVED, either the > handler triggers a completion and another thread does rdma_connect() or > the handler directly calls rdma_connect(). > > In all cases rdma_connect() needs to hold the handler_mutex, but when > handler's are invoked this is already held by the core code. This causes > ULPs using the 2nd method to deadlock. > > Provide a rdma_connect_locked() and have all ULPs call it from their > handlers. > > Reported-by: Guoqing Jiang > Fixes: 2a7cec538169 ("RDMA/cma: Fix locking for the RDMA_CM_CONNECT state" > Signed-off-by: Jason Gunthorpe > --- > drivers/infiniband/core/cma.c | 39 +++++++++++++++++++++--- > drivers/infiniband/ulp/iser/iser_verbs.c | 2 +- > drivers/infiniband/ulp/rtrs/rtrs-clt.c | 4 +-- > drivers/nvme/host/rdma.c | 10 +++--- > include/rdma/rdma_cm.h | 13 +------- > net/rds/ib_cm.c | 5 +-- > 6 files changed, 47 insertions(+), 26 deletions(-) > > Seems people are not testing these four ULPs against rdma-next.. Here is a > quick fix for the issue: > > https://lore.kernel.org/r/3b1f7767-98e2-93e0-b718-16d1c5346140@cloud.ionos.com > > Jason > > diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c > index 7c2ab1f2fbea37..2eaaa1292fb847 100644 > --- a/drivers/infiniband/core/cma.c > +++ b/drivers/infiniband/core/cma.c > @@ -405,10 +405,10 @@ static int cma_comp_exch(struct rdma_id_private *id_priv, > /* > * The FSM uses a funny double locking where state is protected by both > * the handler_mutex and the spinlock. State is not allowed to change > - * away from a handler_mutex protected value without also holding > + * to/from a handler_mutex protected value without also holding > * handler_mutex. > */ > - if (comp == RDMA_CM_CONNECT) > + if (comp == RDMA_CM_CONNECT || exch == RDMA_CM_CONNECT) > lockdep_assert_held(&id_priv->handler_mutex); > > spin_lock_irqsave(&id_priv->lock, flags); > @@ -4038,13 +4038,20 @@ static int cma_connect_iw(struct rdma_id_private *id_priv, > return ret; > } > > -int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param) > +/** > + * rdma_connect_locked - Initiate an active connection request. > + * @id: Connection identifier to connect. > + * @conn_param: Connection information used for connected QPs. > + * > + * Same as rdma_connect() but can only be called from the > + * RDMA_CM_EVENT_ROUTE_RESOLVED handler callback. > + */ > +int rdma_connect_locked(struct rdma_cm_id *id, struct rdma_conn_param *conn_param) > { > struct rdma_id_private *id_priv = > container_of(id, struct rdma_id_private, id); > int ret; > > - mutex_lock(&id_priv->handler_mutex); > if (!cma_comp_exch(id_priv, RDMA_CM_ROUTE_RESOLVED, RDMA_CM_CONNECT)) { > ret = -EINVAL; > goto err_unlock; > @@ -4071,6 +4078,30 @@ int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param) > err_state: > cma_comp_exch(id_priv, RDMA_CM_CONNECT, RDMA_CM_ROUTE_RESOLVED); > err_unlock: > + return ret; > +} > +EXPORT_SYMBOL(rdma_connect_locked); > + > +/** > + * rdma_connect - Initiate an active connection request. > + * @id: Connection identifier to connect. > + * @conn_param: Connection information used for connected QPs. > + * > + * Users must have resolved a route for the rdma_cm_id to connect with by having > + * called rdma_resolve_route before calling this routine. > + * > + * This call will either connect to a remote QP or obtain remote QP information > + * for unconnected rdma_cm_id's. The actual operation is based on the > + * rdma_cm_id's port space. > + */ > +int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param) > +{ > + struct rdma_id_private *id_priv = > + container_of(id, struct rdma_id_private, id); > + int ret; > + > + mutex_lock(&id_priv->handler_mutex); > + ret = rdma_connect_locked(id, conn_param); > mutex_unlock(&id_priv->handler_mutex); > return ret; > } > diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c > index 2f3ebc0a75d924..2bd18b00689341 100644 > --- a/drivers/infiniband/ulp/iser/iser_verbs.c > +++ b/drivers/infiniband/ulp/iser/iser_verbs.c > @@ -620,7 +620,7 @@ static void iser_route_handler(struct rdma_cm_id *cma_id) > conn_param.private_data = (void *)&req_hdr; > conn_param.private_data_len = sizeof(struct iser_cm_hdr); > > - ret = rdma_connect(cma_id, &conn_param); > + ret = rdma_connect_locked(cma_id, &conn_param); > if (ret) { > iser_err("failure connecting: %d\n", ret); > goto failure; > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c > index 776e89231c52f7..f298adc02acba2 100644 > --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c > +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c > @@ -1674,9 +1674,9 @@ static int rtrs_rdma_route_resolved(struct rtrs_clt_con *con) > uuid_copy(&msg.sess_uuid, &sess->s.uuid); > uuid_copy(&msg.paths_uuid, &clt->paths_uuid); > > - err = rdma_connect(con->c.cm_id, ¶m); > + err = rdma_connect_locked(con->c.cm_id, ¶m); > if (err) > - rtrs_err(clt, "rdma_connect(): %d\n", err); > + rtrs_err(clt, "rdma_connect_locked(): %d\n", err); > > return err; > } For rtrs, looks good to me! Thanks for the quick fix. Acked-by: Jack Wang