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 9D9E7C64EC4 for ; Thu, 9 Mar 2023 08:44:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229945AbjCIIo1 (ORCPT ); Thu, 9 Mar 2023 03:44:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229976AbjCIIoV (ORCPT ); Thu, 9 Mar 2023 03:44:21 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9E2A25B86; Thu, 9 Mar 2023 00:44:18 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E292661A3D; Thu, 9 Mar 2023 08:44:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08326C433EF; Thu, 9 Mar 2023 08:44:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1678351457; bh=DKaB/D9PUCGpL0kWQhfiUMr0nDnIES/Fa9vPcRZkArY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NLpMZszO4Y+lOex7F5/UHD11VgIjWd02e9YEGMG1787kagOhUPOHGBiMsSrLY3hRu 2qwhmcZKfW8PjLbmpky5Q3dYLtp3BW3FZTvUv/n36QjeF8c3lIFPVNd6hl4RWJ9Q+9 wY9UUSfVFR073kxhs26K96OxFPRkARR9c3z80sfKeYiO46t2B54Mupcbm3GhvIbEpY VoIuolrDrQiKPDP7IGBWhaB/aNmUCGC4jPoWCnCwPeUNSAfQqrH7744DRD92LRsT3v nOZhuVS1Lt19Ry7kSG2AuPxx7hi2A+kzRoWEFVYI+r1WkS9UjFY2vJ4VG5Vcbymkri zPCWwC8nhf8kg== Date: Thu, 9 Mar 2023 10:44:01 +0200 From: Mike Rapoport To: Axel Rasmussen Cc: Alexander Viro , Andrew Morton , Hugh Dickins , Jan Kara , "Liam R. Howlett" , Matthew Wilcox , Mike Kravetz , Muchun Song , Nadav Amit , Peter Xu , Shuah Khan , James Houghton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v4 2/4] mm: userfaultfd: don't pass around both mm and vma Message-ID: References: <20230308221932.1548827-1-axelrasmussen@google.com> <20230308221932.1548827-3-axelrasmussen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230308221932.1548827-3-axelrasmussen@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 08, 2023 at 02:19:30PM -0800, Axel Rasmussen wrote: > Quite a few userfaultfd functions took both mm and vma pointers as > arguments. Since the mm is trivially accessible via vma->vm_mm, there's > no reason to pass both; it just needlessly extends the already long > argument list. > > Get rid of the mm pointer, where possible, to shorten the argument list. > > Acked-by: Peter Xu > Signed-off-by: Axel Rasmussen Acked-by: Mike Rapoport (IBM) > --- > fs/userfaultfd.c | 2 +- > include/linux/hugetlb.h | 5 ++- > include/linux/shmem_fs.h | 4 +-- > include/linux/userfaultfd_k.h | 4 +-- > mm/hugetlb.c | 4 +-- > mm/shmem.c | 7 ++-- > mm/userfaultfd.c | 61 +++++++++++++++++------------------ > 7 files changed, 41 insertions(+), 46 deletions(-) > > diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c > index 365bf00dd8dd..84d5d402214a 100644 > --- a/fs/userfaultfd.c > +++ b/fs/userfaultfd.c > @@ -1629,7 +1629,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, > > /* Reset ptes for the whole vma range if wr-protected */ > if (userfaultfd_wp(vma)) > - uffd_wp_range(mm, vma, start, vma_end - start, false); > + uffd_wp_range(vma, start, vma_end - start, false); > > new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS; > prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags, > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 8f0467bf1cbd..8b9325f77ac3 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -158,7 +158,7 @@ unsigned long hugetlb_total_pages(void); > vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, > unsigned long address, unsigned int flags); > #ifdef CONFIG_USERFAULTFD > -int hugetlb_mfill_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte, > +int hugetlb_mfill_atomic_pte(pte_t *dst_pte, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > unsigned long src_addr, > @@ -393,8 +393,7 @@ static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb, > } > > #ifdef CONFIG_USERFAULTFD > -static inline int hugetlb_mfill_atomic_pte(struct mm_struct *dst_mm, > - pte_t *dst_pte, > +static inline int hugetlb_mfill_atomic_pte(pte_t *dst_pte, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > unsigned long src_addr, > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h > index 103d1000a5a2..b82916c25e61 100644 > --- a/include/linux/shmem_fs.h > +++ b/include/linux/shmem_fs.h > @@ -151,14 +151,14 @@ extern void shmem_uncharge(struct inode *inode, long pages); > > #ifdef CONFIG_USERFAULTFD > #ifdef CONFIG_SHMEM > -extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > +extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > unsigned long src_addr, > bool zeropage, bool wp_copy, > struct page **pagep); > #else /* !CONFIG_SHMEM */ > -#define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \ > +#define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \ > src_addr, zeropage, wp_copy, pagep) ({ BUG(); 0; }) > #endif /* CONFIG_SHMEM */ > #endif /* CONFIG_USERFAULTFD */ > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > index 468080125612..ba79e296fcc7 100644 > --- a/include/linux/userfaultfd_k.h > +++ b/include/linux/userfaultfd_k.h > @@ -56,7 +56,7 @@ enum mcopy_atomic_mode { > MCOPY_ATOMIC_CONTINUE, > }; > > -extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > +extern int mfill_atomic_install_pte(pmd_t *dst_pmd, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, struct page *page, > bool newly_allocated, bool wp_copy); > @@ -73,7 +73,7 @@ extern ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long dst > extern int mwriteprotect_range(struct mm_struct *dst_mm, > unsigned long start, unsigned long len, > bool enable_wp, atomic_t *mmap_changing); > -extern long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *vma, > +extern long uffd_wp_range(struct vm_area_struct *vma, > unsigned long start, unsigned long len, bool enable_wp); > > /* mm helpers */ > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 4c9276549394..fe043034ab46 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -6157,8 +6157,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, > * Used by userfaultfd UFFDIO_* ioctls. Based on userfaultfd's mfill_atomic_pte > * with modifications for hugetlb pages. > */ > -int hugetlb_mfill_atomic_pte(struct mm_struct *dst_mm, > - pte_t *dst_pte, > +int hugetlb_mfill_atomic_pte(pte_t *dst_pte, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > unsigned long src_addr, > @@ -6166,6 +6165,7 @@ int hugetlb_mfill_atomic_pte(struct mm_struct *dst_mm, > struct page **pagep, > bool wp_copy) > { > + struct mm_struct *dst_mm = dst_vma->vm_mm; > bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE); > struct hstate *h = hstate_vma(dst_vma); > struct address_space *mapping = dst_vma->vm_file->f_mapping; > diff --git a/mm/shmem.c b/mm/shmem.c > index 448f393d8ab2..1d751b6cf1ac 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -2415,8 +2415,7 @@ static struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block > } > > #ifdef CONFIG_USERFAULTFD > -int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > - pmd_t *dst_pmd, > +int shmem_mfill_atomic_pte(pmd_t *dst_pmd, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > unsigned long src_addr, > @@ -2506,11 +2505,11 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, > goto out_release; > > ret = shmem_add_to_page_cache(folio, mapping, pgoff, NULL, > - gfp & GFP_RECLAIM_MASK, dst_mm); > + gfp & GFP_RECLAIM_MASK, dst_vma->vm_mm); > if (ret) > goto out_release; > > - ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, > + ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr, > &folio->page, true, wp_copy); > if (ret) > goto out_delete_from_cache; > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > index 84db5b2fad3a..4fc373476739 100644 > --- a/mm/userfaultfd.c > +++ b/mm/userfaultfd.c > @@ -55,12 +55,13 @@ struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, > * This function handles both MCOPY_ATOMIC_NORMAL and _CONTINUE for both shmem > * and anon, and for both shared and private VMAs. > */ > -int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > +int mfill_atomic_install_pte(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; > + struct mm_struct *dst_mm = dst_vma->vm_mm; > pte_t _dst_pte, *dst_pte; > bool writable = dst_vma->vm_flags & VM_WRITE; > bool vm_shared = dst_vma->vm_flags & VM_SHARED; > @@ -127,8 +128,7 @@ int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, > return ret; > } > > -static int mfill_atomic_pte_copy(struct mm_struct *dst_mm, > - pmd_t *dst_pmd, > +static int mfill_atomic_pte_copy(pmd_t *dst_pmd, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > unsigned long src_addr, > @@ -190,10 +190,10 @@ static int mfill_atomic_pte_copy(struct mm_struct *dst_mm, > __SetPageUptodate(page); > > ret = -ENOMEM; > - if (mem_cgroup_charge(page_folio(page), dst_mm, GFP_KERNEL)) > + if (mem_cgroup_charge(page_folio(page), dst_vma->vm_mm, GFP_KERNEL)) > goto out_release; > > - ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, > + ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr, > page, true, wp_copy); > if (ret) > goto out_release; > @@ -204,8 +204,7 @@ static int mfill_atomic_pte_copy(struct mm_struct *dst_mm, > goto out; > } > > -static int mfill_atomic_pte_zeropage(struct mm_struct *dst_mm, > - pmd_t *dst_pmd, > +static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd, > struct vm_area_struct *dst_vma, > unsigned long dst_addr) > { > @@ -217,7 +216,7 @@ static int mfill_atomic_pte_zeropage(struct mm_struct *dst_mm, > > _dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), > dst_vma->vm_page_prot)); > - dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); > + dst_pte = pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl); > if (dst_vma->vm_file) { > /* the shmem MAP_PRIVATE case requires checking the i_size */ > inode = dst_vma->vm_file->f_inode; > @@ -230,7 +229,7 @@ static int mfill_atomic_pte_zeropage(struct mm_struct *dst_mm, > ret = -EEXIST; > if (!pte_none(*dst_pte)) > goto out_unlock; > - set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); > + set_pte_at(dst_vma->vm_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); > ret = 0; > @@ -240,8 +239,7 @@ static int mfill_atomic_pte_zeropage(struct mm_struct *dst_mm, > } > > /* Handles UFFDIO_CONTINUE for all shmem VMAs (shared or private). */ > -static int mfill_atomic_pte_continue(struct mm_struct *dst_mm, > - pmd_t *dst_pmd, > +static int mfill_atomic_pte_continue(pmd_t *dst_pmd, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > bool wp_copy) > @@ -269,7 +267,7 @@ static int mfill_atomic_pte_continue(struct mm_struct *dst_mm, > goto out_release; > } > > - ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, > + ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr, > page, false, wp_copy); > if (ret) > goto out_release; > @@ -310,7 +308,7 @@ static pmd_t *mm_alloc_pmd(struct mm_struct *mm, unsigned long address) > * mfill_atomic processing for HUGETLB vmas. Note that this routine is > * called with mmap_lock held, it will release mmap_lock before returning. > */ > -static __always_inline ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm, > +static __always_inline ssize_t mfill_atomic_hugetlb( > struct vm_area_struct *dst_vma, > unsigned long dst_start, > unsigned long src_start, > @@ -318,6 +316,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm, > enum mcopy_atomic_mode mode, > bool wp_copy) > { > + struct mm_struct *dst_mm = dst_vma->vm_mm; > int vm_shared = dst_vma->vm_flags & VM_SHARED; > ssize_t err; > pte_t *dst_pte; > @@ -411,7 +410,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm, > goto out_unlock; > } > > - err = hugetlb_mfill_atomic_pte(dst_mm, dst_pte, dst_vma, > + err = hugetlb_mfill_atomic_pte(dst_pte, dst_vma, > dst_addr, src_addr, mode, &page, > wp_copy); > > @@ -463,17 +462,15 @@ static __always_inline ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm, > } > #else /* !CONFIG_HUGETLB_PAGE */ > /* fail at build time if gcc attempts to use this */ > -extern ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm, > - struct vm_area_struct *dst_vma, > - unsigned long dst_start, > - unsigned long src_start, > - unsigned long len, > - enum mcopy_atomic_mode mode, > - bool wp_copy); > +extern ssize_t mfill_atomic_hugetlb(struct vm_area_struct *dst_vma, > + unsigned long dst_start, > + unsigned long src_start, > + unsigned long len, > + enum mcopy_atomic_mode mode, > + bool wp_copy); > #endif /* CONFIG_HUGETLB_PAGE */ > > -static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm, > - pmd_t *dst_pmd, > +static __always_inline ssize_t mfill_atomic_pte(pmd_t *dst_pmd, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > unsigned long src_addr, > @@ -484,7 +481,7 @@ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm, > ssize_t err; > > if (mode == MCOPY_ATOMIC_CONTINUE) { > - return mfill_atomic_pte_continue(dst_mm, dst_pmd, dst_vma, > + return mfill_atomic_pte_continue(dst_pmd, dst_vma, > dst_addr, wp_copy); > } > > @@ -500,14 +497,14 @@ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm, > */ > if (!(dst_vma->vm_flags & VM_SHARED)) { > if (mode == MCOPY_ATOMIC_NORMAL) > - err = mfill_atomic_pte_copy(dst_mm, dst_pmd, dst_vma, > + err = mfill_atomic_pte_copy(dst_pmd, dst_vma, > dst_addr, src_addr, page, > wp_copy); > else > - err = mfill_atomic_pte_zeropage(dst_mm, dst_pmd, > + err = mfill_atomic_pte_zeropage(dst_pmd, > dst_vma, dst_addr); > } else { > - err = shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, > + err = shmem_mfill_atomic_pte(dst_pmd, dst_vma, > dst_addr, src_addr, > mode != MCOPY_ATOMIC_NORMAL, > wp_copy, page); > @@ -588,7 +585,7 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, > * If this is a HUGETLB vma, pass off to appropriate routine > */ > if (is_vm_hugetlb_page(dst_vma)) > - return mfill_atomic_hugetlb(dst_mm, dst_vma, dst_start, > + return mfill_atomic_hugetlb(dst_vma, dst_start, > src_start, len, mcopy_mode, > wp_copy); > > @@ -641,7 +638,7 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm, > BUG_ON(pmd_none(*dst_pmd)); > BUG_ON(pmd_trans_huge(*dst_pmd)); > > - err = mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, > + err = mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, > src_addr, &page, mcopy_mode, wp_copy); > cond_resched(); > > @@ -710,7 +707,7 @@ ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long start, > mmap_changing, 0); > } > > -long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma, > +long uffd_wp_range(struct vm_area_struct *dst_vma, > unsigned long start, unsigned long len, bool enable_wp) > { > unsigned int mm_cp_flags; > @@ -730,7 +727,7 @@ long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma, > */ > if (!enable_wp && vma_wants_manual_pte_write_upgrade(dst_vma)) > mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE; > - tlb_gather_mmu(&tlb, dst_mm); > + tlb_gather_mmu(&tlb, dst_vma->vm_mm); > ret = change_protection(&tlb, dst_vma, start, start + len, mm_cp_flags); > tlb_finish_mmu(&tlb); > > @@ -782,7 +779,7 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, > goto out_unlock; > } > > - err = uffd_wp_range(dst_mm, dst_vma, start, len, enable_wp); > + err = uffd_wp_range(dst_vma, start, len, enable_wp); > > /* Return 0 on success, <0 on failures */ > if (err > 0) > -- > 2.40.0.rc1.284.g88254d51c5-goog > -- Sincerely yours, Mike.