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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 0C8F5C433E1 for ; Tue, 11 Aug 2020 12:07:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB3D82075D for ; Tue, 11 Aug 2020 12:07:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597147673; bh=DE9u+AZbwxmoUIf00n3omuOkrp8vlcn7yOpCyp+NoSw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Y9oM7t5UPpQenYcuhWmUJO2XJu6+L5QHCE9dPoaKVI5ZBBz5ZZFDoJjk1sZdaYxxg 9H3EOjtIxdO2aQbFs4enKwh3BXPKdJ121nKbplptu7ul6gN5WgcwnPCDRioxFuEFZb kZMmazCYR8PCMpvTK0j/J3juliRTQWFDlYeVFiMQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728917AbgHKMHv (ORCPT ); Tue, 11 Aug 2020 08:07:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:38044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728790AbgHKMHh (ORCPT ); Tue, 11 Aug 2020 08:07:37 -0400 Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 67C482075D; Tue, 11 Aug 2020 12:07:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597147656; bh=DE9u+AZbwxmoUIf00n3omuOkrp8vlcn7yOpCyp+NoSw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=0k4fcqC04giD79CpkksNcUo2OCqFx8g0KjieHzJOE4HxWIQbCme4uDfIZsfJ8J329 h0fg6yqiLkunYMWZZbvqsOP/gYZnv0zg8rJrz+iTxzgG7MCbSLNUR31YxAPY5KPZUe ZM/OsjlIN1T6QalwpJR1jMiEE4+TEB9xd8V26kgQ= Date: Tue, 11 Aug 2020 15:07:32 +0300 From: Leon Romanovsky To: Danil Kipnis Cc: Jinpu Wang , Haris Iqbal , linux-rdma@vger.kernel.org, Doug Ledford , Jason Gunthorpe , linux-block@vger.kernel.org, kernel test robot Subject: Re: [PATCH v2] RDMA/rtrs-srv: Incorporate ib_register_client into rtrs server init Message-ID: <20200811120732.GE634816@unreal> References: <20200810115049.304118-1-haris.iqbal@cloud.ionos.com> <20200811084544.GB634816@unreal> <20200811104711.GC634816@unreal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Tue, Aug 11, 2020 at 01:44:58PM +0200, Danil Kipnis wrote: > On Tue, Aug 11, 2020 at 1:13 PM Jinpu Wang wrote: > > > > On Tue, Aug 11, 2020 at 12:53 PM Haris Iqbal > > wrote: > > > > > > On Tue, Aug 11, 2020 at 4:17 PM Leon Romanovsky wrote: > > > > > > > > On Tue, Aug 11, 2020 at 02:27:12PM +0530, Haris Iqbal wrote: > > > > > On Tue, Aug 11, 2020 at 2:15 PM Leon Romanovsky wrote: > > > > > > > > > > > > On Mon, Aug 10, 2020 at 05:20:49PM +0530, Md Haris Iqbal wrote: > > > > > > > The rnbd_server module's communication manager (cm) initialization depends > > > > > > > on the registration of the "network namespace subsystem" of the RDMA CM > > > > > > > agent module. As such, when the kernel is configured to load the > > > > > > > rnbd_server and the RDMA cma module during initialization; and if the > > > > > > > rnbd_server module is initialized before RDMA cma module, a null ptr > > > > > > > dereference occurs during the RDMA bind operation. > > > > > > > > > > > > > > Call trace below, > > > > > > > > > > > > > > [ 1.904782] Call Trace: > > > > > > > [ 1.904782] ? xas_load+0xd/0x80 > > > > > > > [ 1.904782] xa_load+0x47/0x80 > > > > > > > [ 1.904782] cma_ps_find+0x44/0x70 > > > > > > > [ 1.904782] rdma_bind_addr+0x782/0x8b0 > > > > > > > [ 1.904782] ? get_random_bytes+0x35/0x40 > > > > > > > [ 1.904782] rtrs_srv_cm_init+0x50/0x80 > > > > > > > [ 1.904782] rtrs_srv_open+0x102/0x180 > > > > > > > [ 1.904782] ? rnbd_client_init+0x6e/0x6e > > > > > > > [ 1.904782] rnbd_srv_init_module+0x34/0x84 > > > > > > > [ 1.904782] ? rnbd_client_init+0x6e/0x6e > > > > > > > [ 1.904782] do_one_initcall+0x4a/0x200 > > > > > > > [ 1.904782] kernel_init_freeable+0x1f1/0x26e > > > > > > > [ 1.904782] ? rest_init+0xb0/0xb0 > > > > > > > [ 1.904782] kernel_init+0xe/0x100 > > > > > > > [ 1.904782] ret_from_fork+0x22/0x30 > > > > > > > [ 1.904782] Modules linked in: > > > > > > > [ 1.904782] CR2: 0000000000000015 > > > > > > > [ 1.904782] ---[ end trace c42df88d6c7b0a48 ]--- > > > > > > > > > > > > > > All this happens cause the cm init is in the call chain of the module init, > > > > > > > which is not a preferred practice. > > > > > > > > > > > > > > So remove the call to rdma_create_id() from the module init call chain. > > > > > > > Instead register rtrs-srv as an ib client, which makes sure that the > > > > > > > rdma_create_id() is called only when an ib device is added. > > > > > > > > > > > > > > Fixes: 9cb837480424 ("RDMA/rtrs: server: main functionality") > > > > > > > Reported-by: kernel test robot > > > > > > > Signed-off-by: Md Haris Iqbal > > > > > > > --- > > > > > > > Change in v2: > > > > > > > Use only single variable to track number of IB devices and failure > > > > > > > Change according to kernel coding style > > > > > > > > > > > > > > drivers/infiniband/ulp/rtrs/rtrs-srv.c | 79 +++++++++++++++++++++++++- > > > > > > > drivers/infiniband/ulp/rtrs/rtrs-srv.h | 6 ++ > > > > > > > 2 files changed, 82 insertions(+), 3 deletions(-) > > > > > > > > > > > > > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > > > > > index 0d9241f5d9e6..69a37ce73b0c 100644 > > > > > > > --- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > > > > > +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > > > > > @@ -16,6 +16,7 @@ > > > > > > > #include "rtrs-srv.h" > > > > > > > #include "rtrs-log.h" > > > > > > > #include > > > > > > > +#include > > > > > > > > > > > > > > MODULE_DESCRIPTION("RDMA Transport Server"); > > > > > > > MODULE_LICENSE("GPL"); > > > > > > > @@ -31,6 +32,7 @@ MODULE_LICENSE("GPL"); > > > > > > > static struct rtrs_rdma_dev_pd dev_pd; > > > > > > > static mempool_t *chunk_pool; > > > > > > > struct class *rtrs_dev_class; > > > > > > > +static struct rtrs_srv_ib_ctx ib_ctx; > > > > > > > > > > > > > > static int __read_mostly max_chunk_size = DEFAULT_MAX_CHUNK_SIZE; > > > > > > > static int __read_mostly sess_queue_depth = DEFAULT_SESS_QUEUE_DEPTH; > > > > > > > @@ -2033,6 +2035,64 @@ static void free_srv_ctx(struct rtrs_srv_ctx *ctx) > > > > > > > kfree(ctx); > > > > > > > } > > > > > > > > > > > > > > +static int rtrs_srv_add_one(struct ib_device *device) > > > > > > > +{ > > > > > > > + struct rtrs_srv_ctx *ctx; > > > > > > > + int ret; > > > > > > > + > > > > > > > + if (ib_ctx.ib_dev_count) > > > > > > > + goto out; > > > > > > > + > > > > > > > + /* > > > > > > > + * Since our CM IDs are NOT bound to any ib device we will create them > > > > > > > + * only once > > > > > > > + */ > > > > > > > + ctx = ib_ctx.srv_ctx; > > > > > > > + ret = rtrs_srv_rdma_init(ctx, ib_ctx.port); > > > > > > > + if (ret) { > > > > > > > + /* > > > > > > > + * We errored out here. > > > > > > > + * According to the ib code, if we encounter an error here then the > > > > > > > + * error code is ignored, and no more calls to our ops are made. > > > > > > > + */ > > > > > > > + pr_err("Failed to initialize RDMA connection"); > > > > > > > + ib_ctx.ib_dev_count = -1; > > > > > > > + return ret; > > > > > > > + } > > > > > > > + > > > > > > > +out: > > > > > > > + /* > > > > > > > + * Keep a track on the number of ib devices added > > > > > > > + */ > > > > > > > + ib_ctx.ib_dev_count++; > > > > > > > + > > > > > > > + return 0; > > > > > > > +} > > > > > > > + > > > > > > > +static void rtrs_srv_remove_one(struct ib_device *device, void *client_data) > > > > > > > +{ > > > > > > > + struct rtrs_srv_ctx *ctx; > > > > > > > + > > > > > > > + ib_ctx.ib_dev_count--; > > > > > > > + > > > > > > > + if (ib_ctx.ib_dev_count) > > > > > > > + return; > > > > > > > + > > > > > > > + /* > > > > > > > + * Since our CM IDs are NOT bound to any ib device we will remove them > > > > > > > + * only once, when the last device is removed > > > > > > > + */ > > > > > > > + ctx = ib_ctx.srv_ctx; > > > > > > > + rdma_destroy_id(ctx->cm_id_ip); > > > > > > > + rdma_destroy_id(ctx->cm_id_ib); > > > > > > > +} > > > > > > > + > > > > > > > +static struct ib_client rtrs_srv_client = { > > > > > > > + .name = "rtrs_server", > > > > > > > + .add = rtrs_srv_add_one, > > > > > > > + .remove = rtrs_srv_remove_one > > > > > > > +}; > > > > > > > + > > > > > > > /** > > > > > > > * rtrs_srv_open() - open RTRS server context > > > > > > > * @ops: callback functions > > > > > > > @@ -2051,12 +2111,26 @@ struct rtrs_srv_ctx *rtrs_srv_open(struct rtrs_srv_ops *ops, u16 port) > > > > > > > if (!ctx) > > > > > > > return ERR_PTR(-ENOMEM); > > > > > > > > > > > > > > - err = rtrs_srv_rdma_init(ctx, port); > > > > > > > + ib_ctx = (struct rtrs_srv_ib_ctx) { > > > > > > > + .srv_ctx = ctx, > > > > > > > + .port = port, > > > > > > > + }; > > > > > > > + > > > > > > > + err = ib_register_client(&rtrs_srv_client); > > > > > > > if (err) { > > > > > > > free_srv_ctx(ctx); > > > > > > > return ERR_PTR(err); > > > > > > > } > > > > > > > > > > > > > > + /* > > > > > > > + * Since ib_register_client does not propagate the device add error > > > > > > > + * we check if .add was called and the RDMA connection init failed > > > > > > > + */ > > > > > > > + if (ib_ctx.ib_dev_count < 0) { > > > > > > > + free_srv_ctx(ctx); > > > > > > > + return ERR_PTR(-ENODEV); > > > > > > > + } > > > > > > > > > > > > I afraid that you overcomplicated here, ib_register_client() doesn't > > > > > > return error if ->add() for specific device failed, it doesn't mean > > > > > > that ->add won't be called again for another device. > > > > > > > > > > > > So you don't need to use ib_dev_count == -1, just keep it to be 0 and > > > > > > leave to rtrs_srv_close() to free srv_ctx. > > > > > > > > > > Leaving it 0 when there is an error is not gonna work. Since when the > > > > > modules are all built-in, a call to ib_register_client() will not > > > > > result in a call to ->add() then and there. So ib_register_client() > > > > > will return after registering the client, but without calling ->add(). > > > > > Which means, ib_dev_count would be 0. > > > > > > > > If ib_dev_count == 0 => rtrs_srv_rdma_init() didn't success => nothing > > > > to release. > > > > > > True, but we have to send a failure back to the caller of > > > "rtrs_srv_open()" (and user of this ulp); which in our case is > > > rnbd-srv's function rnbd_srv_init_module(). > > > In our case, the rnbd-drv module init would fail if "rtrs_srv_open()" > > > fails, meaning rtrs_srv_rdma_init() had failed. > > > > > > Even if we are talking in generic terms, any module calling the > > > "rtrs_srv_open()" of the rtrs ulp, would want to know if the server > > > open failed or succeeded right? > > I think Leon is right, any success of call to ->add, we have something > > to rtrs_srv_rdma_init, > > we can consider rtrs_srv_open is success instead of an error. > > I don't think Leon is right. In case when all modules are built in, > add is not called in place when ib_client_register is called (cause > there are no registered devices and add_client_context will be called > at some later point in time from enable_device_and_get instead). So we > have two cases: built in and not built in. Then there is a possibility > that rtrs_srv_rdma_init fails (create_id, bind_addr, etc.) or doesn't > fail. Particularly we need to separate the case where add hasn't been > called at all yet (i.e. modules are built in, we just need to wait > until add gets called and then can start listening) and the case where > it did get called but failed (i.e. modules are not built in it got > called but failed - in that case we need to refuse to load module and > return error since we can't start listening). > The latter case is indicated by ib_dev_count = -1. I think it would > make code easier to read if instead of setting ib_dev_count to -1 and > explicitly checking whether it's below 0, one would introduce an > additional variable for the error code returned by rtrs_srv_rdma_init > and check it instead. Sorry, but it is very hard to read this block without indentations. Anyway, as I said there should be no difference in behaviour between no devices and first device failed to initialize. Thanks > > > > > Thanks Leon for catching this. > > > > Regards!