From patchwork Mon Nov 7 16:17:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13034674 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 587E3C43219 for ; Mon, 7 Nov 2022 16:21:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232616AbiKGQVJ (ORCPT ); Mon, 7 Nov 2022 11:21:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232192AbiKGQUb (ORCPT ); Mon, 7 Nov 2022 11:20:31 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7CBD21813 for ; Mon, 7 Nov 2022 08:19:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667837943; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AeUaEmlrMw4ArQRkwlp+ErKAfQOnAwux6TH3g3VKyx8=; b=efXn79Wo80RreUcgDtRtVI1PTvEgWMq3TtNkBPXxH+UN52qPQDMlEXE3wDX2vS/DSCpv1g Vloe04rJLYi0vFEuZvZdpoBbkzRqNgToAbndPmQWhGuxZU/aKOnLzx4uhHqcyiY3Bvo6nw 6pL1FgngbwJv0JP3o6EXsNYtm5VPhmw= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-189-sW-YJI4aPeex8JowzFHqOQ-1; Mon, 07 Nov 2022 11:18:54 -0500 X-MC-Unique: sW-YJI4aPeex8JowzFHqOQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 74EDC8027F5; Mon, 7 Nov 2022 16:18:52 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.195.106]) by smtp.corp.redhat.com (Postfix) with ESMTP id BB8874B400F; Mon, 7 Nov 2022 16:18:46 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-kselftest@vger.kernel.org, David Hildenbrand , Linus Torvalds , Andrew Morton , Jason Gunthorpe , John Hubbard , Peter Xu , Greg Kroah-Hartman , Andrea Arcangeli , Hugh Dickins , Nadav Amit , Vlastimil Babka , Matthew Wilcox , Mike Kravetz , Muchun Song , Lucas Stach , David Airlie , Oded Gabbay , Arnd Bergmann , Christian Benvenuti , Nelson Escobar , Leon Romanovsky Subject: [PATCH RFC 11/19] RDMA/usnic: remove FOLL_FORCE usage Date: Mon, 7 Nov 2022 17:17:32 +0100 Message-Id: <20221107161740.144456-12-david@redhat.com> In-Reply-To: <20221107161740.144456-1-david@redhat.com> References: <20221107161740.144456-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org GUP now supports reliable R/O long-term pinning in COW mappings, such that we break COW early. MAP_SHARED VMAs only use the shared zeropage so far in one corner case (DAXFS file with holes), which can be ignored because GUP does not support long-term pinning in fsdax (see check_vma_flags()). Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop using FOLL_FORCE, which is really only for debugger access. Cc: Christian Benvenuti Cc: Nelson Escobar Cc: Jason Gunthorpe Cc: Leon Romanovsky Signed-off-by: David Hildenbrand --- drivers/infiniband/hw/usnic/usnic_uiom.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c index 67923ced6e2d..c301b3be9f30 100644 --- a/drivers/infiniband/hw/usnic/usnic_uiom.c +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c @@ -85,6 +85,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, int dmasync, struct usnic_uiom_reg *uiomr) { struct list_head *chunk_list = &uiomr->chunk_list; + unsigned int gup_flags = FOLL_LONGTERM; struct page **page_list; struct scatterlist *sg; struct usnic_uiom_chunk *chunk; @@ -96,7 +97,6 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, int off; int i; dma_addr_t pa; - unsigned int gup_flags; struct mm_struct *mm; /* @@ -131,8 +131,8 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, goto out; } - gup_flags = FOLL_WRITE; - gup_flags |= (writable) ? 0 : FOLL_FORCE; + if (writable) + gup_flags |= FOLL_WRITE; cur_base = addr & PAGE_MASK; ret = 0; @@ -140,8 +140,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, ret = pin_user_pages(cur_base, min_t(unsigned long, npages, PAGE_SIZE / sizeof(struct page *)), - gup_flags | FOLL_LONGTERM, - page_list, NULL); + gup_flags, page_list, NULL); if (ret < 0) goto out;