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=-24.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL 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 D629CC433ED for ; Thu, 6 May 2021 21:13:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3FF261177 for ; Thu, 6 May 2021 21:13:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230155AbhEFVOW (ORCPT ); Thu, 6 May 2021 17:14:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53418 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229968AbhEFVOR (ORCPT ); Thu, 6 May 2021 17:14:17 -0400 Received: from mail-qt1-x82b.google.com (mail-qt1-x82b.google.com [IPv6:2607:f8b0:4864:20::82b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E64ECC0613ED for ; Thu, 6 May 2021 14:13:17 -0700 (PDT) Received: by mail-qt1-x82b.google.com with SMTP id f8so999550qth.6 for ; Thu, 06 May 2021 14:13:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=RIxjuE33E7abAYMCMrXM50GaBY0vVKTUwZ41pzyN8mw=; b=vReVRGzSSRnZQlAPvJ2DacbKod0eIA0ssz5lX+asfZZg6uy3eRr+wGUPBBqAHJIQie 7ks2vWl/MUqITz5IsQH2dmW6V7jIG+xy/KYRnDq/QNf5XD3FjECe8zSe4KORTYSJ2ZRq Llp0gaWSoZB0Z9R0UjG9PaV6HmFCU9z2N+d4e0DrOVZFEbRzhcqtkzvqqxPk2JbRpzPh nFjXOgcyLy2612p+uKpG7QWQjPtu0reqF4HU+lwDhPW4sctgmt0ZDT9NBRi3t7eIuB+z 8wJd3IX/SreTsc0cVpAqH9PrASzE1K4IuF8Pv9krQAqA6pyfvz0iEgwHwh0x0njngTn3 2sBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=RIxjuE33E7abAYMCMrXM50GaBY0vVKTUwZ41pzyN8mw=; b=QyQmG2hkbp+1/ALPfyoTFZoLxJbG1Pl7cv0/8FewfmMKIbUa693p+vyxEqUObtLFg9 5GJbaOJBuyljAvLnnJBdh0wnlmwigqRKHdyHueGbfo6gRvFV4rEA3/ArrHVu/rVRtXRq ZYXLJCPlUfAtqwbCN3ttDtCYGj+Mbgc9mLrDybFoxzhCB3fasSWrYuJfTycNf0MOi04c NyTrrkL5V1OX5aZJNSzeNrhqmUI6liquG4vB7mmyPhKadTQmgij32c0Vpxqwn2Wj/G2R Zt2k66ceq8suP/M6VFEvjcC2xTgAB3UEsDMXCIkPCXRluZUIxkm8YIWxK/osZ/sOL1E2 0lMQ== X-Gm-Message-State: AOAM532mtR+GHayrHmAEGSM1gX5htPhVg0m++LlgMUtvn3TnzHctdi4O Dng/qDmEtXnldyl1YoLANL9Dug== X-Google-Smtp-Source: ABdhPJwFMLMm7IMnquula3QCavOTg+gg74rWfhuq1EJmCOuYsiMfW5eCmRctYncEQYduQsFmbTASgA== X-Received: by 2002:a05:622a:3cc:: with SMTP id k12mr6387909qtx.233.1620335596632; Thu, 06 May 2021 14:13:16 -0700 (PDT) Received: from eggly.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id t203sm3062531qke.83.2021.05.06.14.13.13 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Thu, 06 May 2021 14:13:15 -0700 (PDT) Date: Thu, 6 May 2021 14:12:59 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Axel Rasmussen cc: Alexander Viro , Andrea Arcangeli , Andrew Morton , Hugh Dickins , Jerome Glisse , Joe Perches , Lokesh Gidra , Mike Kravetz , Mike Rapoport , Peter Xu , Shaohua Li , Shuah Khan , Stephen Rothwell , Wang Qing , linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, Brian Geffon , "Dr . David Alan Gilbert" , Mina Almasry , Oliver Upton Subject: Re: [PATCH v6 06/10] userfaultfd/shmem: modify shmem_mfill_atomic_pte to use install_pte() In-Reply-To: <20210503180737.2487560-7-axelrasmussen@google.com> Message-ID: References: <20210503180737.2487560-1-axelrasmussen@google.com> <20210503180737.2487560-7-axelrasmussen@google.com> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 3 May 2021, Axel Rasmussen wrote: > In a previous commit, we added the mfill_atomic_install_pte() helper. > This helper does the job of setting up PTEs for an existing page, to map > it into a given VMA. It deals with both the anon and shmem cases, as > well as the shared and private cases. > > In other words, shmem_mfill_atomic_pte() duplicates a case it already > handles. So, expose it, and let shmem_mfill_atomic_pte() use it > directly, to reduce code duplication. > > This requires that we refactor shmem_mfill_atomic_pte() a bit: > > Instead of doing accounting (shmem_recalc_inode() et al) part-way > through the PTE setup, do it afterward. This frees up > mfill_atomic_install_pte() from having to care about this accounting, > and means we don't need to e.g. shmem_uncharge() in the error path. > > A side effect is this switches shmem_mfill_atomic_pte() to use > lru_cache_add_inactive_or_unevictable() instead of just lru_cache_add(). > This wrapper does some extra accounting in an exceptional case, if > appropriate, so it's actually the more correct thing to use. > > Signed-off-by: Axel Rasmussen Acked-by: Hugh Dickins And thanks for doing those late mcopy->mfill renamings, I think those represent Andrea's intent better. As far as I'm concerned, this series is now ripe for picking into mmotm (bearing in mind the dependencies you noted in 00/10): thank you Axel. > --- > include/linux/userfaultfd_k.h | 5 +++ > mm/shmem.c | 58 ++++++++--------------------------- > mm/userfaultfd.c | 17 ++++------ > 3 files changed, 23 insertions(+), 57 deletions(-) > > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > index 794d1538b8ba..331d2ccf0bcc 100644 > --- a/include/linux/userfaultfd_k.h > +++ b/include/linux/userfaultfd_k.h > @@ -53,6 +53,11 @@ enum mcopy_atomic_mode { > MCOPY_ATOMIC_CONTINUE, > }; > > +extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > + struct vm_area_struct *dst_vma, > + unsigned long dst_addr, struct page *page, > + bool newly_allocated, bool wp_copy); > + > extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, > unsigned long src_start, unsigned long len, > bool *mmap_changing, __u64 mode); > diff --git a/mm/shmem.c b/mm/shmem.c > index e361f1d81c8d..2e9f56c83489 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -2378,14 +2378,11 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > struct address_space *mapping = inode->i_mapping; > gfp_t gfp = mapping_gfp_mask(mapping); > pgoff_t pgoff = linear_page_index(dst_vma, dst_addr); > - spinlock_t *ptl; > void *page_kaddr; > struct page *page; > - pte_t _dst_pte, *dst_pte; > int ret; > pgoff_t max_off; > > - ret = -ENOMEM; > if (!shmem_inode_acct_block(inode, 1)) { > /* > * We may have got a page, returned -ENOENT triggering a retry, > @@ -2396,10 +2393,11 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > put_page(*pagep); > *pagep = NULL; > } > - goto out; > + return -ENOMEM; > } > > if (!*pagep) { > + ret = -ENOMEM; > page = shmem_alloc_page(gfp, info, pgoff); > if (!page) > goto out_unacct_blocks; > @@ -2414,9 +2412,9 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > /* fallback to copy_from_user outside mmap_lock */ > if (unlikely(ret)) { > *pagep = page; > - shmem_inode_unacct_blocks(inode, 1); > + ret = -ENOENT; > /* don't free the page */ > - return -ENOENT; > + goto out_unacct_blocks; > } > } else { /* ZEROPAGE */ > clear_highpage(page); > @@ -2442,32 +2440,10 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > if (ret) > goto out_release; > > - _dst_pte = mk_pte(page, dst_vma->vm_page_prot); > - if (dst_vma->vm_flags & VM_WRITE) > - _dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte)); > - else { > - /* > - * We don't set the pte dirty if the vma has no > - * VM_WRITE permission, so mark the page dirty or it > - * could be freed from under us. We could do it > - * unconditionally before unlock_page(), but doing it > - * only if VM_WRITE is not set is faster. > - */ > - set_page_dirty(page); > - } > - > - dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); > - > - ret = -EFAULT; > - max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); > - if (unlikely(pgoff >= max_off)) > - goto out_release_unlock; > - > - ret = -EEXIST; > - if (!pte_none(*dst_pte)) > - goto out_release_unlock; > - > - lru_cache_add(page); > + ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, > + page, true, false); > + if (ret) > + goto out_delete_from_cache; > > spin_lock_irq(&info->lock); > info->alloced++; > @@ -2475,27 +2451,17 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > shmem_recalc_inode(inode); > spin_unlock_irq(&info->lock); > > - inc_mm_counter(dst_mm, mm_counter_file(page)); > - page_add_file_rmap(page, false); > - set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); > - > - /* No need to invalidate - it was non-present before */ > - update_mmu_cache(dst_vma, dst_addr, dst_pte); > - pte_unmap_unlock(dst_pte, ptl); > + SetPageDirty(page); > unlock_page(page); > - ret = 0; > -out: > - return ret; > -out_release_unlock: > - pte_unmap_unlock(dst_pte, ptl); > - ClearPageDirty(page); > + return 0; > +out_delete_from_cache: > delete_from_page_cache(page); > out_release: > unlock_page(page); > put_page(page); > out_unacct_blocks: > shmem_inode_unacct_blocks(inode, 1); > - goto out; > + return ret; > } > #endif /* CONFIG_USERFAULTFD */ > > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > index d1ac73a0d2a9..5508f7d9e2dc 100644 > --- a/mm/userfaultfd.c > +++ b/mm/userfaultfd.c > @@ -51,18 +51,13 @@ struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, > /* > * Install PTEs, to map dst_addr (within dst_vma) to page. > * > - * This function handles MCOPY_ATOMIC_CONTINUE (which is always file-backed), > - * whether or not dst_vma is VM_SHARED. It also handles the more general > - * MCOPY_ATOMIC_NORMAL case, when dst_vma is *not* VM_SHARED (it may be file > - * backed, or not). > - * > - * Note that MCOPY_ATOMIC_NORMAL for a VM_SHARED dst_vma is handled by > - * shmem_mcopy_atomic_pte instead. > + * This function handles both MCOPY_ATOMIC_NORMAL and _CONTINUE for both shmem > + * and anon, and for both shared and private VMAs. > */ > -static int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > - struct vm_area_struct *dst_vma, > - unsigned long dst_addr, struct page *page, > - bool newly_allocated, bool wp_copy) > +int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > + struct vm_area_struct *dst_vma, > + unsigned long dst_addr, struct page *page, > + bool newly_allocated, bool wp_copy) > { > int ret; > pte_t _dst_pte, *dst_pte; > -- > 2.31.1.527.g47e6f16901-goog > > 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=-24.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL 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 739ECC433ED for ; Thu, 6 May 2021 21:13:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B032A61289 for ; Thu, 6 May 2021 21:13:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B032A61289 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AB0136B0070; Thu, 6 May 2021 17:13:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A5F9C6B0071; Thu, 6 May 2021 17:13:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8B1EA6B0072; Thu, 6 May 2021 17:13:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0063.hostedemail.com [216.40.44.63]) by kanga.kvack.org (Postfix) with ESMTP id 6C3516B0070 for ; Thu, 6 May 2021 17:13:18 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 132AA6105 for ; Thu, 6 May 2021 21:13:18 +0000 (UTC) X-FDA: 78112056876.13.DB613D0 Received: from mail-qt1-f175.google.com (mail-qt1-f175.google.com [209.85.160.175]) by imf20.hostedemail.com (Postfix) with ESMTP id 67120D5 for ; Thu, 6 May 2021 21:13:10 +0000 (UTC) Received: by mail-qt1-f175.google.com with SMTP id 1so5201940qtb.0 for ; Thu, 06 May 2021 14:13:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=RIxjuE33E7abAYMCMrXM50GaBY0vVKTUwZ41pzyN8mw=; b=vReVRGzSSRnZQlAPvJ2DacbKod0eIA0ssz5lX+asfZZg6uy3eRr+wGUPBBqAHJIQie 7ks2vWl/MUqITz5IsQH2dmW6V7jIG+xy/KYRnDq/QNf5XD3FjECe8zSe4KORTYSJ2ZRq Llp0gaWSoZB0Z9R0UjG9PaV6HmFCU9z2N+d4e0DrOVZFEbRzhcqtkzvqqxPk2JbRpzPh nFjXOgcyLy2612p+uKpG7QWQjPtu0reqF4HU+lwDhPW4sctgmt0ZDT9NBRi3t7eIuB+z 8wJd3IX/SreTsc0cVpAqH9PrASzE1K4IuF8Pv9krQAqA6pyfvz0iEgwHwh0x0njngTn3 2sBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=RIxjuE33E7abAYMCMrXM50GaBY0vVKTUwZ41pzyN8mw=; b=hpPuAWCcvCp2/lJT7anCtAn4Bp9L7virNX2p+cPfHDve4J7t1YbIvX5Kayqxm1d9H6 VzeI5Gpd2BPbXVblS2yxFwM1NDz4E2QGroiX7MegvhjEL1dcPR0BIGnW+cWaW6Bjgc9O RblGES03IljndzI46PX4FANbdTH9L1x6wnN5l0la6ydD3vTTZWIyuUqyfD1Bxb3VjvQQ jgCoKokBsegGLWmrlRN+ZaHsmTTyLhc0/XRu88/RuTKTvOoUlitCqXBOnc3ZDnk+InBL Hl4wvJ5boazpA7QwCqFeMh+Dz3QynfUuJV94fVIpf9CwqK6ToJFg5RfHQCk8MGAs4p+g HtWg== X-Gm-Message-State: AOAM532TNKb3UxI2HHMfg6Q6J2cJ+gG0BRE7luplZWIoIXSKd/DtolzP QbmncjMT06P2Z/QTVGsW76gzdQ== X-Google-Smtp-Source: ABdhPJwFMLMm7IMnquula3QCavOTg+gg74rWfhuq1EJmCOuYsiMfW5eCmRctYncEQYduQsFmbTASgA== X-Received: by 2002:a05:622a:3cc:: with SMTP id k12mr6387909qtx.233.1620335596632; Thu, 06 May 2021 14:13:16 -0700 (PDT) Received: from eggly.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id t203sm3062531qke.83.2021.05.06.14.13.13 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Thu, 06 May 2021 14:13:15 -0700 (PDT) Date: Thu, 6 May 2021 14:12:59 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Axel Rasmussen cc: Alexander Viro , Andrea Arcangeli , Andrew Morton , Hugh Dickins , Jerome Glisse , Joe Perches , Lokesh Gidra , Mike Kravetz , Mike Rapoport , Peter Xu , Shaohua Li , Shuah Khan , Stephen Rothwell , Wang Qing , linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, Brian Geffon , "Dr . David Alan Gilbert" , Mina Almasry , Oliver Upton Subject: Re: [PATCH v6 06/10] userfaultfd/shmem: modify shmem_mfill_atomic_pte to use install_pte() In-Reply-To: <20210503180737.2487560-7-axelrasmussen@google.com> Message-ID: References: <20210503180737.2487560-1-axelrasmussen@google.com> <20210503180737.2487560-7-axelrasmussen@google.com> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 67120D5 X-Stat-Signature: 7ukfozsxfmtm9fpc95tbw91411cs4qjy Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=vReVRGzS; spf=pass (imf20.hostedemail.com: domain of hughd@google.com designates 209.85.160.175 as permitted sender) smtp.mailfrom=hughd@google.com; dmarc=pass (policy=reject) header.from=google.com Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf20; identity=mailfrom; envelope-from=""; helo=mail-qt1-f175.google.com; client-ip=209.85.160.175 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620335590-912462 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 3 May 2021, Axel Rasmussen wrote: > In a previous commit, we added the mfill_atomic_install_pte() helper. > This helper does the job of setting up PTEs for an existing page, to map > it into a given VMA. It deals with both the anon and shmem cases, as > well as the shared and private cases. > > In other words, shmem_mfill_atomic_pte() duplicates a case it already > handles. So, expose it, and let shmem_mfill_atomic_pte() use it > directly, to reduce code duplication. > > This requires that we refactor shmem_mfill_atomic_pte() a bit: > > Instead of doing accounting (shmem_recalc_inode() et al) part-way > through the PTE setup, do it afterward. This frees up > mfill_atomic_install_pte() from having to care about this accounting, > and means we don't need to e.g. shmem_uncharge() in the error path. > > A side effect is this switches shmem_mfill_atomic_pte() to use > lru_cache_add_inactive_or_unevictable() instead of just lru_cache_add(). > This wrapper does some extra accounting in an exceptional case, if > appropriate, so it's actually the more correct thing to use. > > Signed-off-by: Axel Rasmussen Acked-by: Hugh Dickins And thanks for doing those late mcopy->mfill renamings, I think those represent Andrea's intent better. As far as I'm concerned, this series is now ripe for picking into mmotm (bearing in mind the dependencies you noted in 00/10): thank you Axel. > --- > include/linux/userfaultfd_k.h | 5 +++ > mm/shmem.c | 58 ++++++++--------------------------- > mm/userfaultfd.c | 17 ++++------ > 3 files changed, 23 insertions(+), 57 deletions(-) > > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > index 794d1538b8ba..331d2ccf0bcc 100644 > --- a/include/linux/userfaultfd_k.h > +++ b/include/linux/userfaultfd_k.h > @@ -53,6 +53,11 @@ enum mcopy_atomic_mode { > MCOPY_ATOMIC_CONTINUE, > }; > > +extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > + struct vm_area_struct *dst_vma, > + unsigned long dst_addr, struct page *page, > + bool newly_allocated, bool wp_copy); > + > extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, > unsigned long src_start, unsigned long len, > bool *mmap_changing, __u64 mode); > diff --git a/mm/shmem.c b/mm/shmem.c > index e361f1d81c8d..2e9f56c83489 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -2378,14 +2378,11 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > struct address_space *mapping = inode->i_mapping; > gfp_t gfp = mapping_gfp_mask(mapping); > pgoff_t pgoff = linear_page_index(dst_vma, dst_addr); > - spinlock_t *ptl; > void *page_kaddr; > struct page *page; > - pte_t _dst_pte, *dst_pte; > int ret; > pgoff_t max_off; > > - ret = -ENOMEM; > if (!shmem_inode_acct_block(inode, 1)) { > /* > * We may have got a page, returned -ENOENT triggering a retry, > @@ -2396,10 +2393,11 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > put_page(*pagep); > *pagep = NULL; > } > - goto out; > + return -ENOMEM; > } > > if (!*pagep) { > + ret = -ENOMEM; > page = shmem_alloc_page(gfp, info, pgoff); > if (!page) > goto out_unacct_blocks; > @@ -2414,9 +2412,9 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > /* fallback to copy_from_user outside mmap_lock */ > if (unlikely(ret)) { > *pagep = page; > - shmem_inode_unacct_blocks(inode, 1); > + ret = -ENOENT; > /* don't free the page */ > - return -ENOENT; > + goto out_unacct_blocks; > } > } else { /* ZEROPAGE */ > clear_highpage(page); > @@ -2442,32 +2440,10 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > if (ret) > goto out_release; > > - _dst_pte = mk_pte(page, dst_vma->vm_page_prot); > - if (dst_vma->vm_flags & VM_WRITE) > - _dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte)); > - else { > - /* > - * We don't set the pte dirty if the vma has no > - * VM_WRITE permission, so mark the page dirty or it > - * could be freed from under us. We could do it > - * unconditionally before unlock_page(), but doing it > - * only if VM_WRITE is not set is faster. > - */ > - set_page_dirty(page); > - } > - > - dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); > - > - ret = -EFAULT; > - max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); > - if (unlikely(pgoff >= max_off)) > - goto out_release_unlock; > - > - ret = -EEXIST; > - if (!pte_none(*dst_pte)) > - goto out_release_unlock; > - > - lru_cache_add(page); > + ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, > + page, true, false); > + if (ret) > + goto out_delete_from_cache; > > spin_lock_irq(&info->lock); > info->alloced++; > @@ -2475,27 +2451,17 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > shmem_recalc_inode(inode); > spin_unlock_irq(&info->lock); > > - inc_mm_counter(dst_mm, mm_counter_file(page)); > - page_add_file_rmap(page, false); > - set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); > - > - /* No need to invalidate - it was non-present before */ > - update_mmu_cache(dst_vma, dst_addr, dst_pte); > - pte_unmap_unlock(dst_pte, ptl); > + SetPageDirty(page); > unlock_page(page); > - ret = 0; > -out: > - return ret; > -out_release_unlock: > - pte_unmap_unlock(dst_pte, ptl); > - ClearPageDirty(page); > + return 0; > +out_delete_from_cache: > delete_from_page_cache(page); > out_release: > unlock_page(page); > put_page(page); > out_unacct_blocks: > shmem_inode_unacct_blocks(inode, 1); > - goto out; > + return ret; > } > #endif /* CONFIG_USERFAULTFD */ > > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > index d1ac73a0d2a9..5508f7d9e2dc 100644 > --- a/mm/userfaultfd.c > +++ b/mm/userfaultfd.c > @@ -51,18 +51,13 @@ struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, > /* > * Install PTEs, to map dst_addr (within dst_vma) to page. > * > - * This function handles MCOPY_ATOMIC_CONTINUE (which is always file-backed), > - * whether or not dst_vma is VM_SHARED. It also handles the more general > - * MCOPY_ATOMIC_NORMAL case, when dst_vma is *not* VM_SHARED (it may be file > - * backed, or not). > - * > - * Note that MCOPY_ATOMIC_NORMAL for a VM_SHARED dst_vma is handled by > - * shmem_mcopy_atomic_pte instead. > + * This function handles both MCOPY_ATOMIC_NORMAL and _CONTINUE for both shmem > + * and anon, and for both shared and private VMAs. > */ > -static int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > - struct vm_area_struct *dst_vma, > - unsigned long dst_addr, struct page *page, > - bool newly_allocated, bool wp_copy) > +int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > + struct vm_area_struct *dst_vma, > + unsigned long dst_addr, struct page *page, > + bool newly_allocated, bool wp_copy) > { > int ret; > pte_t _dst_pte, *dst_pte; > -- > 2.31.1.527.g47e6f16901-goog > >