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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 AFCACC3F2D1 for ; Mon, 2 Mar 2020 09:58:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8508F21D56 for ; Mon, 2 Mar 2020 09:58:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cloud.ionos.com header.i=@cloud.ionos.com header.b="g15Sio73" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726956AbgCBJ6x (ORCPT ); Mon, 2 Mar 2020 04:58:53 -0500 Received: from mail-io1-f68.google.com ([209.85.166.68]:36178 "EHLO mail-io1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727060AbgCBJ6w (ORCPT ); Mon, 2 Mar 2020 04:58:52 -0500 Received: by mail-io1-f68.google.com with SMTP id d15so10837807iog.3 for ; Mon, 02 Mar 2020 01:58:52 -0800 (PST) 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=CgZRkqKTlqTPulCP/Z/qQC513Xv4FPfpHxLuqBbnjAk=; b=g15Sio73VOBgipZ8AqV6rXMyYIH/FjaISdLiWSdC0XmkFQK+jkP4oZSNp6y/GdqjvG Vk69oGdMYQnk1lUJZ5SlEM1Mg+lKO1i+ZTC9DtuG4tW8F+uQ3BYFah4NT+Qj+gASTqoO ABFI0wguzqgwePZGt9Pz36/0A9sc+SgdBXMOCNw+PSIlEI+maRoa/Gw7pVf4+vyxciIv OL7f6Lln0QoTsRidgU1ktWoemibzEbYsgjvUspDQP3o6V1ME5QJ0AVvGRQQjwW5UOWGi 3b5sFXoEGc4prtPB9Rj3ZcN5YUMNwqnvJyJ/9qnffZCK2a7h3uCuWzYo3NYy9sR7a3I1 2jUw== 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=CgZRkqKTlqTPulCP/Z/qQC513Xv4FPfpHxLuqBbnjAk=; b=Ikhd8Xa8Zrgxvn9qyYSDhMuqWq1PL7pXYzhE+KQxMQ9FTg/eSp9D+R+uq6WSDGMWzQ x8i127FOO6X4BdYrDtAVvHGUW81qBJwVgfqNkc4bVHLd9l0Y1xnLbRMnpTIe/KKWrcnp MkVT1WLAAtc0TZ7zVUqSIw1ogkP7zTjs/B353x3Joxp91b3cQIuGuz0G9wZmUpfFRf2F LACyKT9llokSK4hb8XARS+82Gi/9CUaQwo1+5xEAhydUPCeKEORnxmZ4b4YW+Xet+wUl 487R48V+SJ9Qf6TMaaOofp9wAniAgP/5Az3B+zPx0JsG3G/gbH2se7esRLVFjL8gAf+d htdQ== X-Gm-Message-State: APjAAAU2iXqO1S+6O1oKydB27u+BYQLVL4Uar4SnfEovOXyTjRhtSDwg 83EH/hf4aNUZNiMqJ5zoeUTK9sjsq8fFv/ZjgxMv X-Google-Smtp-Source: APXvYqyIpuywT4gaQSZZrGI4CtG5X618MR1wirAOy2xoXfW/vaZpNm0TtwxRfClkClwj0az1I5CQ1qO0+duuQ8nfLG8= X-Received: by 2002:a02:caa8:: with SMTP id e8mr6403877jap.126.1583143131655; Mon, 02 Mar 2020 01:58:51 -0800 (PST) MIME-Version: 1.0 References: <20200221104721.350-1-jinpuwang@gmail.com> <20200221104721.350-21-jinpuwang@gmail.com> <33864f54-62af-cb5f-45fa-55a283dcd434@acm.org> In-Reply-To: <33864f54-62af-cb5f-45fa-55a283dcd434@acm.org> From: Danil Kipnis Date: Mon, 2 Mar 2020 10:58:40 +0100 Message-ID: Subject: Re: [PATCH v9 20/25] block/rnbd: server: main functionality To: Bart Van Assche Cc: Jack Wang , linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, Jens Axboe , Christoph Hellwig , Sagi Grimberg , Leon Romanovsky , Doug Ledford , Jason Gunthorpe , Jack Wang , rpenyaev@suse.de, pankaj.gupta@cloud.ionos.com Content-Type: text/plain; charset="UTF-8" Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Sun, Mar 1, 2020 at 3:58 AM Bart Van Assche wrote: > > On 2020-02-21 02:47, Jack Wang wrote: > > +static int dev_search_path_set(const char *val, const struct kernel_param *kp) > > +{ > > + char *dup; > > + > > + if (strlen(val) >= sizeof(dev_search_path)) > > + return -EINVAL; > > + > > + dup = kstrdup(val, GFP_KERNEL); > > + > > + if (dup[strlen(dup) - 1] == '\n') > > + dup[strlen(dup) - 1] = '\0'; > > + > > + strlcpy(dev_search_path, dup, sizeof(dev_search_path)); > > + > > + kfree(dup); > > + pr_info("dev_search_path changed to '%s'\n", dev_search_path); > > + > > + return 0; > > +} > > It is not necessary in this function to do memory allocation. Something > like the following (untested) code should be sufficient: > > const char *p = strrchr(val, '\n') ? : val + strlen(val); > > snprintf(dev_search_path, sizeof(dev_search_path), "%.*s", > (int)(p - val), val); > > How are concurrent attempts to change dev_search_path serialized? > Hi Bart, thanks a lot for your comments. Will try to avoid the allocation. The module parameter is readonly. It's only set during module init - I guess we don't need to handle concurrent access? Best, Danil. > Thanks, > > Bart.