From patchwork Fri Mar 19 01:52:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shiyang Ruan X-Patchwork-Id: 12149659 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 40A99C433E6 for ; Fri, 19 Mar 2021 01:54:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1594264ED2 for ; Fri, 19 Mar 2021 01:54:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231599AbhCSBx2 (ORCPT ); Thu, 18 Mar 2021 21:53:28 -0400 Received: from mail.cn.fujitsu.com ([183.91.158.132]:41437 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S230326AbhCSBw5 (ORCPT ); Thu, 18 Mar 2021 21:52:57 -0400 IronPort-HdrOrdr: A9a23:JZLcc63gENSHbs7H5SXv2wqjBFIkLtp033Aq2lEZdDV+dMuEm8ey2MkKzBOcskd0ZFgMu/ClfJOBT3TV6IJv7eAqUIuKcQH6tAKTQr1KwofvzjbpES+71sM1781dWodkDtmYNzlHpOLbxCX9LNo62tmA98mT9ILj5lNgVxtjZa0lzyoRMHf5LmRMSANLBYU0GfOnj6IpmxObZX8VYs6nb0N1PdTrmtujrvLbSC9DLxsmxS3Ltjmw9YP9eiLy4j4uFx9J3pcumFKorzDE X-IronPort-AV: E=Sophos;i="5.81,259,1610380800"; d="scan'208";a="105876651" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 19 Mar 2021 09:52:55 +0800 Received: from G08CNEXMBPEKD04.g08.fujitsu.local (unknown [10.167.33.201]) by cn.fujitsu.com (Postfix) with ESMTP id 78EEC4CEA875; Fri, 19 Mar 2021 09:52:53 +0800 (CST) Received: from G08CNEXCHPEKD04.g08.fujitsu.local (10.167.33.200) by G08CNEXMBPEKD04.g08.fujitsu.local (10.167.33.201) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 19 Mar 2021 09:52:48 +0800 Received: from irides.mr.mr.mr (10.167.225.141) by G08CNEXCHPEKD04.g08.fujitsu.local (10.167.33.209) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 19 Mar 2021 09:52:47 +0800 From: Shiyang Ruan To: , , , CC: , , , , , , , , , Subject: [PATCH v3 02/10] fsdax: Factor helper: dax_fault_actor() Date: Fri, 19 Mar 2021 09:52:29 +0800 Message-ID: <20210319015237.993880-3-ruansy.fnst@fujitsu.com> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210319015237.993880-1-ruansy.fnst@fujitsu.com> References: <20210319015237.993880-1-ruansy.fnst@fujitsu.com> MIME-Version: 1.0 X-yoursite-MailScanner-ID: 78EEC4CEA875.A6113 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: ruansy.fnst@fujitsu.com Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The core logic in the two dax page fault functions is similar. So, move the logic into a common helper function. Also, to facilitate the addition of new features, such as CoW, switch-case is no longer used to handle different iomap types. Signed-off-by: Shiyang Ruan Reviewed-by: Christoph Hellwig --- fs/dax.c | 291 +++++++++++++++++++++++++++---------------------------- 1 file changed, 145 insertions(+), 146 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 7031e4302b13..33ddad0f3091 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1053,6 +1053,66 @@ static vm_fault_t dax_load_hole(struct xa_state *xas, return ret; } +#ifdef CONFIG_FS_DAX_PMD +static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, + struct iomap *iomap, void **entry) +{ + struct address_space *mapping = vmf->vma->vm_file->f_mapping; + unsigned long pmd_addr = vmf->address & PMD_MASK; + struct vm_area_struct *vma = vmf->vma; + struct inode *inode = mapping->host; + pgtable_t pgtable = NULL; + struct page *zero_page; + spinlock_t *ptl; + pmd_t pmd_entry; + pfn_t pfn; + + zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); + + if (unlikely(!zero_page)) + goto fallback; + + pfn = page_to_pfn_t(zero_page); + *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, + DAX_PMD | DAX_ZERO_PAGE, false); + + if (arch_needs_pgtable_deposit()) { + pgtable = pte_alloc_one(vma->vm_mm); + if (!pgtable) + return VM_FAULT_OOM; + } + + ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); + if (!pmd_none(*(vmf->pmd))) { + spin_unlock(ptl); + goto fallback; + } + + if (pgtable) { + pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); + mm_inc_nr_ptes(vma->vm_mm); + } + pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); + pmd_entry = pmd_mkhuge(pmd_entry); + set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); + spin_unlock(ptl); + trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry); + return VM_FAULT_NOPAGE; + +fallback: + if (pgtable) + pte_free(vma->vm_mm, pgtable); + trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry); + return VM_FAULT_FALLBACK; +} +#else +static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, + struct iomap *iomap, void **entry) +{ + return VM_FAULT_FALLBACK; +} +#endif /* CONFIG_FS_DAX_PMD */ + s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap) { sector_t sector = iomap_sector(iomap, pos & PAGE_MASK); @@ -1289,6 +1349,61 @@ static int dax_fault_cow_page(struct vm_fault *vmf, struct iomap *iomap, return 0; } +/** + * dax_fault_actor - Common actor to handle pfn insertion in PTE/PMD fault. + * @vmf: vm fault instance + * @pfnp: pfn to be returned + * @xas: the dax mapping tree of a file + * @entry: an unlocked dax entry to be inserted + * @pmd: distinguish whether it is a pmd fault + * @flags: iomap flags + * @iomap: from iomap_begin() + * @srcmap: from iomap_begin(), not equal to iomap if it is a CoW + */ +static vm_fault_t dax_fault_actor(struct vm_fault *vmf, pfn_t *pfnp, + struct xa_state *xas, void *entry, bool pmd, unsigned int flags, + struct iomap *iomap, struct iomap *srcmap) +{ + struct address_space *mapping = vmf->vma->vm_file->f_mapping; + size_t size = pmd ? PMD_SIZE : PAGE_SIZE; + loff_t pos = (loff_t)xas->xa_offset << PAGE_SHIFT; + bool write = vmf->flags & FAULT_FLAG_WRITE; + bool sync = dax_fault_is_synchronous(flags, vmf->vma, iomap); + int err = 0; + pfn_t pfn; + + /* if we are reading UNWRITTEN and HOLE, return a hole. */ + if (!write && + (iomap->type == IOMAP_UNWRITTEN || iomap->type == IOMAP_HOLE)) { + if (!pmd) + return dax_load_hole(xas, mapping, &entry, vmf); + else + return dax_pmd_load_hole(xas, vmf, iomap, &entry); + } + + if (iomap->type != IOMAP_MAPPED) { + WARN_ON_ONCE(1); + return VM_FAULT_SIGBUS; + } + + err = dax_iomap_pfn(iomap, pos, size, &pfn); + if (err) + return dax_fault_return(err); + + entry = dax_insert_entry(xas, mapping, vmf, entry, pfn, 0, + write && !sync); + + if (sync) + return dax_fault_synchronous_pfnp(pfnp, pfn); + + if (pmd) + return vmf_insert_pfn_pmd(vmf, pfn, write); + if (write) + return vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); + else + return vmf_insert_mixed(vmf->vma, vmf->address, pfn); +} + static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) { @@ -1296,17 +1411,14 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, struct address_space *mapping = vma->vm_file->f_mapping; XA_STATE(xas, &mapping->i_pages, vmf->pgoff); struct inode *inode = mapping->host; - unsigned long vaddr = vmf->address; loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; struct iomap iomap = { .type = IOMAP_HOLE }; struct iomap srcmap = { .type = IOMAP_HOLE }; unsigned flags = IOMAP_FAULT; int error, major = 0; bool write = vmf->flags & FAULT_FLAG_WRITE; - bool sync; vm_fault_t ret = 0; void *entry; - pfn_t pfn; trace_dax_pte_fault(inode, vmf, ret); /* @@ -1352,8 +1464,8 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, goto unlock_entry; } if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { - error = -EIO; /* fs corruption? */ - goto error_finish_iomap; + ret = VM_FAULT_SIGBUS; /* fs corruption? */ + goto finish_iomap; } if (vmf->cow_page) { @@ -1363,49 +1475,19 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, goto finish_iomap; } - sync = dax_fault_is_synchronous(flags, vma, &iomap); - - switch (iomap.type) { - case IOMAP_MAPPED: - if (iomap.flags & IOMAP_F_NEW) { - count_vm_event(PGMAJFAULT); - count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); - major = VM_FAULT_MAJOR; - } - error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); - if (error < 0) - goto error_finish_iomap; - - entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn, - 0, write && !sync); - - if (sync) { - ret = dax_fault_synchronous_pfnp(pfnp, pfn); - goto finish_iomap; - } - trace_dax_insert_mapping(inode, vmf, entry); - if (write) - ret = vmf_insert_mixed_mkwrite(vma, vaddr, pfn); - else - ret = vmf_insert_mixed(vma, vaddr, pfn); - + ret = dax_fault_actor(vmf, pfnp, &xas, entry, false, flags, + &iomap, &srcmap); + if (ret == VM_FAULT_SIGBUS) goto finish_iomap; - case IOMAP_UNWRITTEN: - case IOMAP_HOLE: - if (!write) { - ret = dax_load_hole(&xas, mapping, &entry, vmf); - goto finish_iomap; - } - fallthrough; - default: - WARN_ON_ONCE(1); - error = -EIO; - break; + + /* read/write MAPPED, CoW UNWRITTEN */ + if (iomap.flags & IOMAP_F_NEW) { + count_vm_event(PGMAJFAULT); + count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); + major = VM_FAULT_MAJOR; } - error_finish_iomap: - ret = dax_fault_return(error); - finish_iomap: +finish_iomap: if (ops->iomap_end) { int copied = PAGE_SIZE; @@ -1419,66 +1501,14 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, */ ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); } - unlock_entry: +unlock_entry: dax_unlock_entry(&xas, entry); - out: +out: trace_dax_pte_fault_done(inode, vmf, ret); return ret | major; } #ifdef CONFIG_FS_DAX_PMD -static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, - struct iomap *iomap, void **entry) -{ - struct address_space *mapping = vmf->vma->vm_file->f_mapping; - unsigned long pmd_addr = vmf->address & PMD_MASK; - struct vm_area_struct *vma = vmf->vma; - struct inode *inode = mapping->host; - pgtable_t pgtable = NULL; - struct page *zero_page; - spinlock_t *ptl; - pmd_t pmd_entry; - pfn_t pfn; - - zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); - - if (unlikely(!zero_page)) - goto fallback; - - pfn = page_to_pfn_t(zero_page); - *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, - DAX_PMD | DAX_ZERO_PAGE, false); - - if (arch_needs_pgtable_deposit()) { - pgtable = pte_alloc_one(vma->vm_mm); - if (!pgtable) - return VM_FAULT_OOM; - } - - ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); - if (!pmd_none(*(vmf->pmd))) { - spin_unlock(ptl); - goto fallback; - } - - if (pgtable) { - pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); - mm_inc_nr_ptes(vma->vm_mm); - } - pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); - pmd_entry = pmd_mkhuge(pmd_entry); - set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); - spin_unlock(ptl); - trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry); - return VM_FAULT_NOPAGE; - -fallback: - if (pgtable) - pte_free(vma->vm_mm, pgtable); - trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry); - return VM_FAULT_FALLBACK; -} - static bool dax_fault_check_fallback(struct vm_fault *vmf, struct xa_state *xas, pgoff_t max_pgoff) { @@ -1519,17 +1549,15 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, struct address_space *mapping = vma->vm_file->f_mapping; XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER); bool write = vmf->flags & FAULT_FLAG_WRITE; - bool sync; - unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; + unsigned int flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; struct inode *inode = mapping->host; - vm_fault_t result = VM_FAULT_FALLBACK; + vm_fault_t ret = VM_FAULT_FALLBACK; struct iomap iomap = { .type = IOMAP_HOLE }; struct iomap srcmap = { .type = IOMAP_HOLE }; pgoff_t max_pgoff; void *entry; loff_t pos; int error; - pfn_t pfn; /* * Check whether offset isn't beyond end of file now. Caller is @@ -1541,7 +1569,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); if (xas.xa_index >= max_pgoff) { - result = VM_FAULT_SIGBUS; + ret = VM_FAULT_SIGBUS; goto out; } @@ -1556,7 +1584,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, */ entry = grab_mapping_entry(&xas, mapping, PMD_ORDER); if (xa_is_internal(entry)) { - result = xa_to_internal(entry); + ret = xa_to_internal(entry); goto fallback; } @@ -1568,7 +1596,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, */ if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && !pmd_devmap(*vmf->pmd)) { - result = 0; + ret = 0; goto unlock_entry; } @@ -1578,49 +1606,21 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, * to look up our filesystem block. */ pos = (loff_t)xas.xa_index << PAGE_SHIFT; - error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap, - &srcmap); + error = ops->iomap_begin(inode, pos, PMD_SIZE, flags, &iomap, &srcmap); if (error) goto unlock_entry; if (iomap.offset + iomap.length < pos + PMD_SIZE) goto finish_iomap; - sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap); - - switch (iomap.type) { - case IOMAP_MAPPED: - error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn); - if (error < 0) - goto finish_iomap; + ret = dax_fault_actor(vmf, pfnp, &xas, entry, true, flags, + &iomap, &srcmap); - entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn, - DAX_PMD, write && !sync); - - if (sync) { - result = dax_fault_synchronous_pfnp(pfnp, pfn); - goto finish_iomap; - } - - trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); - result = vmf_insert_pfn_pmd(vmf, pfn, write); - break; - case IOMAP_UNWRITTEN: - case IOMAP_HOLE: - if (WARN_ON_ONCE(write)) - break; - result = dax_pmd_load_hole(&xas, vmf, &iomap, &entry); - break; - default: - WARN_ON_ONCE(1); - break; - } - - finish_iomap: +finish_iomap: if (ops->iomap_end) { int copied = PMD_SIZE; - if (result == VM_FAULT_FALLBACK) + if (ret == VM_FAULT_FALLBACK) copied = 0; /* * The fault is done by now and there's no way back (other @@ -1628,19 +1628,18 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, * Just ignore error from ->iomap_end since we cannot do much * with it. */ - ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, - &iomap); + ops->iomap_end(inode, pos, PMD_SIZE, copied, flags, &iomap); } - unlock_entry: +unlock_entry: dax_unlock_entry(&xas, entry); - fallback: - if (result == VM_FAULT_FALLBACK) { +fallback: + if (ret == VM_FAULT_FALLBACK) { split_huge_pmd(vma, vmf->pmd, vmf->address); count_vm_event(THP_FAULT_FALLBACK); } out: - trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result); - return result; + trace_dax_pmd_fault_done(inode, vmf, max_pgoff, ret); + return ret; } #else static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,