From patchwork Tue Apr 20 22:07:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Axel Rasmussen X-Patchwork-Id: 12215113 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=-26.3 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_GIT,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 24871C433B4 for ; Tue, 20 Apr 2021 22:08:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFCCB61401 for ; Tue, 20 Apr 2021 22:08:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234252AbhDTWIr (ORCPT ); Tue, 20 Apr 2021 18:08:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234237AbhDTWIq (ORCPT ); Tue, 20 Apr 2021 18:08:46 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B0E1C06174A for ; Tue, 20 Apr 2021 15:08:13 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id u73-20020a25ab4f0000b0290410f38a2f81so13263254ybi.22 for ; Tue, 20 Apr 2021 15:08:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=a4VdN5aYyzVjjL2HqfgoVnRM8+bC3CDsNcvljqmhvtc=; b=uzsUF7c/nqA0cryXPZz+BzIxEuT0aA5ywKIJYlO4mqAho5vbHY/zWzehPflreVIG2/ JmIb9Wuyf2YoHlpe0i9pngk6fbfyjVY6DpRdoIbNjBCDI2n5HVfOppTpjFigNVuf02hq woZKzepGZTNJeHTdUWkQQl6fboDizm2ND/smnXnIVwVyWAMT9F+TlcudnMZRUBKcACZL izVfxyZlL58aCX8mwvjgtLgTG0Y0mZHmRnb0cYpFEWV7v+7/OaBnlhzXU83w1MtVu94/ VLimMmDqIhWhnzofYMN7Q/hVn9nXM+V3tjFHz7pVP83F5Oa6XOdrxquM5wckyUfCXu3R BfQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=a4VdN5aYyzVjjL2HqfgoVnRM8+bC3CDsNcvljqmhvtc=; b=D1jiHVQ+I4SnOvhrpl8JYRoBcfAD0yhJ3Tyzo9iVe7taSeeYlknRNk8EQgSGrnjeAB YBxrh0EBwqLqu2LRwLowae913omiUK8zEDcIYThNUfjYL8rYlH2XpPpdKEnDLiF0QNe/ MSv2UXr9L+ecotfSrHM+TiH2lRWV0aVy81RY58rWyK9p+fz7jBia/oJ6JB5lIGy1uKzK 7aEXU24sujix4KeDbAEkt9p5NkW6W1zlQdRvWj0Z7IoQBctZzBR7SN0llGdFJjpaA48y iuzCU0USXKVPapgLgJsIbR1SPOp/Pm6g+wNvIJLwb4GsMU3vgfofo+2wPVVN1uWYXN4r JG3A== X-Gm-Message-State: AOAM532BRq8sSnnfr0TQcgiq4Pub0OcYKeeNWhke/sEI9Fhu5ftcuONM 0bXRHCLaDph3WLmDlw9+6dmlQrwr8vyLOgOQrL8V X-Google-Smtp-Source: ABdhPJzePMEMmP2y9ogK36u5OfBacHtf6kJR7MjKT30Aj+bxcaQdJ2gVnC91JVbD4LoXtfaXLsiMASeS7IpVHaLZl7KS X-Received: from ajr0.svl.corp.google.com ([2620:15c:2cd:203:c40e:ee2c:2ab8:257a]) (user=axelrasmussen job=sendgmr) by 2002:a5b:28e:: with SMTP id x14mr10647700ybl.493.1618956492299; Tue, 20 Apr 2021 15:08:12 -0700 (PDT) Date: Tue, 20 Apr 2021 15:07:56 -0700 In-Reply-To: <20210420220804.486803-1-axelrasmussen@google.com> Message-Id: <20210420220804.486803-3-axelrasmussen@google.com> Mime-Version: 1.0 References: <20210420220804.486803-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.31.1.368.gbe11c130af-goog Subject: [PATCH v4 02/10] userfaultfd/shmem: combine shmem_{mcopy_atomic,mfill_zeropage}_pte From: Axel Rasmussen To: 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 Cc: linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, Axel Rasmussen , Brian Geffon , "Dr . David Alan Gilbert" , Mina Almasry , Oliver Upton Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Previously, we did a dance where we had one calling path in userfaultfd.c (mfill_atomic_pte), but then we split it into two in shmem_fs.h (shmem_{mcopy_atomic,mfill_zeropage}_pte), and then rejoined into a single shared function in shmem.c (shmem_mfill_atomic_pte). This is all a bit overly complex. Just call the single combined shmem function directly, allowing us to clean up various branches, boilerplate, etc. While we're touching this function, two other small cleanup changes: - offset is equivalent to pgoff, so we can get rid of offset entirely. - Split two VM_BUG_ON cases into two statements. This means the line number reported when the BUG is hit specifies exactly which condition was true. Reviewed-by: Peter Xu Acked-by: Hugh Dickins Signed-off-by: Axel Rasmussen --- include/linux/shmem_fs.h | 17 ++++++------- mm/shmem.c | 52 +++++++++++++--------------------------- mm/userfaultfd.c | 10 +++----- 3 files changed, 26 insertions(+), 53 deletions(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index d82b6f396588..47c3409d02ac 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -122,21 +122,18 @@ static inline bool shmem_file(struct file *file) extern bool shmem_charge(struct inode *inode, long pages); extern void shmem_uncharge(struct inode *inode, long pages); +#ifdef CONFIG_USERFAULTFD #ifdef CONFIG_SHMEM extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, struct vm_area_struct *dst_vma, unsigned long dst_addr, unsigned long src_addr, + bool zeropage, struct page **pagep); -extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm, - pmd_t *dst_pmd, - struct vm_area_struct *dst_vma, - unsigned long dst_addr); -#else -#define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \ - src_addr, pagep) ({ BUG(); 0; }) -#define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \ - dst_addr) ({ BUG(); 0; }) -#endif +#else /* !CONFIG_SHMEM */ +#define shmem_mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \ + src_addr, zeropage, pagep) ({ BUG(); 0; }) +#endif /* CONFIG_SHMEM */ +#endif /* CONFIG_USERFAULTFD */ #endif diff --git a/mm/shmem.c b/mm/shmem.c index 26c76b13ad23..b72c55aa07fc 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2354,13 +2354,14 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode return inode; } -static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, - pmd_t *dst_pmd, - struct vm_area_struct *dst_vma, - unsigned long dst_addr, - unsigned long src_addr, - bool zeropage, - struct page **pagep) +#ifdef CONFIG_USERFAULTFD +int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, + pmd_t *dst_pmd, + struct vm_area_struct *dst_vma, + unsigned long dst_addr, + unsigned long src_addr, + bool zeropage, + struct page **pagep) { struct inode *inode = file_inode(dst_vma->vm_file); struct shmem_inode_info *info = SHMEM_I(inode); @@ -2372,7 +2373,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, struct page *page; pte_t _dst_pte, *dst_pte; int ret; - pgoff_t offset, max_off; + pgoff_t max_off; ret = -ENOMEM; if (!shmem_inode_acct_block(inode, 1)) @@ -2383,7 +2384,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, if (!page) goto out_unacct_blocks; - if (!zeropage) { /* mcopy_atomic */ + if (!zeropage) { /* COPY */ page_kaddr = kmap_atomic(page); ret = copy_from_user(page_kaddr, (const void __user *)src_addr, @@ -2397,7 +2398,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, /* don't free the page */ return -ENOENT; } - } else { /* mfill_zeropage_atomic */ + } else { /* ZEROPAGE */ clear_highpage(page); } } else { @@ -2405,15 +2406,15 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, *pagep = NULL; } - VM_BUG_ON(PageLocked(page) || PageSwapBacked(page)); + VM_BUG_ON(PageLocked(page)); + VM_BUG_ON(PageSwapBacked(page)); __SetPageLocked(page); __SetPageSwapBacked(page); __SetPageUptodate(page); ret = -EFAULT; - offset = linear_page_index(dst_vma, dst_addr); max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); - if (unlikely(offset >= max_off)) + if (unlikely(pgoff >= max_off)) goto out_release; ret = shmem_add_to_page_cache(page, mapping, pgoff, NULL, @@ -2439,7 +2440,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, ret = -EFAULT; max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); - if (unlikely(offset >= max_off)) + if (unlikely(pgoff >= max_off)) goto out_release_unlock; ret = -EEXIST; @@ -2476,28 +2477,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, shmem_inode_unacct_blocks(inode, 1); goto out; } - -int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, - pmd_t *dst_pmd, - struct vm_area_struct *dst_vma, - unsigned long dst_addr, - unsigned long src_addr, - struct page **pagep) -{ - return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, - dst_addr, src_addr, false, pagep); -} - -int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm, - pmd_t *dst_pmd, - struct vm_area_struct *dst_vma, - unsigned long dst_addr) -{ - struct page *page = NULL; - - return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, - dst_addr, 0, true, &page); -} +#endif /* CONFIG_USERFAULTFD */ #ifdef CONFIG_TMPFS static const struct inode_operations shmem_symlink_inode_operations; diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index e14b3820c6a8..23fa2583bbd1 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -440,13 +440,9 @@ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm, dst_vma, dst_addr); } else { VM_WARN_ON_ONCE(wp_copy); - if (!zeropage) - err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd, - dst_vma, dst_addr, - src_addr, page); - else - err = shmem_mfill_zeropage_pte(dst_mm, dst_pmd, - dst_vma, dst_addr); + err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma, + dst_addr, src_addr, zeropage, + page); } return err;