From patchwork Thu Jun 10 16:06:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 12313439 X-Patchwork-Delegate: bhelgaas@google.com 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 B344CC48BD1 for ; Thu, 10 Jun 2021 16:06:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96676613D8 for ; Thu, 10 Jun 2021 16:06:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230201AbhFJQIN (ORCPT ); Thu, 10 Jun 2021 12:08:13 -0400 Received: from ale.deltatee.com ([204.191.154.188]:60124 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230161AbhFJQIM (ORCPT ); Thu, 10 Jun 2021 12:08:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:MIME-Version:References:In-Reply-To: Message-Id:Date:Cc:To:From:content-disposition; bh=kGb8w7OA+VecwjXRg6RAtUZUrHcBmrTzMPMqQqpjkm8=; b=KHxnMIMpdNc7Po5o4zvLt0xMtY O8CKxzCulcw4C6nUH683CeLFb8/OPy+KDkDPcyv4lZKPe9Ummse/RTBVVjCcfwtGlSpEVmXW9pGhK kvazm4kIWUUX8SuJkmpLi1DWXq7JZkffKjpiAV9MNAUinSyzeAUCy5xQqKcpPFQlViqtNAVe9oWgf Mw/6+ukwawWE66h3aLiHwwmnJCb1O7AyiQquQyZIEIeKKKrSfoFF/tr38wMvawcg8HZKkRLB0El2O VtYjZLWaWwcwi8bk0ixvDdJ479NHzzXIfmG3qD6mTjiMvqptMQ/J+zJyIX/ZgYD/bTuV30KMryaq5 wH1K1iDg==; Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lrNCA-0000Ji-Kn; Thu, 10 Jun 2021 10:06:15 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.92) (envelope-from ) id 1lrNC8-0007Pj-Iq; Thu, 10 Jun 2021 10:06:12 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Bjorn Helgaas Cc: Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , =?utf-8?q?Christian_K=C3=B6nig?= , John Hubbard , Don Dutile , Logan Gunthorpe Date: Thu, 10 Jun 2021 10:06:05 -0600 Message-Id: <20210610160609.28447-3-logang@deltatee.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210610160609.28447-1-logang@deltatee.com> References: <20210610160609.28447-1-logang@deltatee.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, helgaas@kernel.org, sbates@raithlin.com, hch@lst.de, dan.j.williams@intel.com, jgg@ziepe.ca, christian.koenig@amd.com, jhubbard@nvidia.com, ddutile@redhat.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [PATCH v1 2/6] PCI/P2PDMA: Use a buffer on the stack for collecting the acs list X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org In order to call the calc_map_type_and_dist_warn() function from a dma_map operation, the function must not sleep. The only reason it sleeps is to allocate memory for the seq_buf to print a verbose warning telling the user how to disable ACS for that path. Instead of allocating the memory with kmalloc, allocate it on the stack with a smaller buffer. A 128B buffer is enough to print 10 pci device names. A system with 10 bridge ports between two devices that have ACS enabled would be unusually large, so this should still be a reasonable limit. This also allows cleaning up the awkward (and broken) return with -ENOMEM which contradicts the return type and the caller was not prepared for. Signed-off-by: Logan Gunthorpe --- drivers/pci/p2pdma.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 6f90e9812f6e..3a5fb63c5f2c 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -500,11 +500,10 @@ calc_map_type_and_dist_warn(struct pci_dev *provider, struct pci_dev *client, { struct seq_buf acs_list; bool acs_redirects; + char buf[128]; int ret; - seq_buf_init(&acs_list, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE); - if (!acs_list.buffer) - return -ENOMEM; + seq_buf_init(&acs_list, buf, sizeof(buf)); ret = calc_map_type_and_dist(provider, client, dist, &acs_redirects, &acs_list); @@ -522,8 +521,6 @@ calc_map_type_and_dist_warn(struct pci_dev *provider, struct pci_dev *client, pci_name(provider)); } - kfree(acs_list.buffer); - return ret; }