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Rao" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , "David S. Miller" , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org Subject: [PATCH v1 07/11] mm/memory: factor out copying the actual PTE in copy_present_pte() Date: Mon, 22 Jan 2024 20:41:56 +0100 Message-ID: <20240122194200.381241-8-david@redhat.com> In-Reply-To: <20240122194200.381241-1-david@redhat.com> References: <20240122194200.381241-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 X-Rspamd-Queue-Id: 4EBF6C0017 X-Rspam-User: X-Stat-Signature: s5e4ke6i7bgg5wsom4iw4ae44kgcdmb3 X-Rspamd-Server: rspam01 X-HE-Tag: 1705952574-194439 X-HE-Meta: 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 ktG6xeOH L1I9GKQoefyoLzERNYA49gc4rTz7iADFa+oY8mIV2GvAJ/nv+OgV5VULop+lrMqKUu2jeyTIWA9b2tldBTvmRapHgkmoikLoanfSZFo3Nxht7zpZ+yAT8w+6tgBacWZFwI6LfcNMUIFuYp+N24YG4rVMdjz3yy+xMcbokgryamomHiWsxpY5rhXAi/sqEh5+q6TEH+C7JGpf9WPEIdZMgShQLsKfwmOrYv58V 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: List-Subscribe: List-Unsubscribe: Let's prepare for further changes. Signed-off-by: David Hildenbrand Reviewed-by: Ryan Roberts --- mm/memory.c | 60 ++++++++++++++++++++++++++++------------------------- 1 file changed, 32 insertions(+), 28 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 7e1f4849463aa..2aa2051ee51d3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -930,6 +930,29 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma return 0; } +static inline void __copy_present_pte(struct vm_area_struct *dst_vma, + struct vm_area_struct *src_vma, pte_t *dst_pte, pte_t *src_pte, + pte_t pte, unsigned long addr) +{ + struct mm_struct *src_mm = src_vma->vm_mm; + + /* If it's a COW mapping, write protect it both processes. */ + if (is_cow_mapping(src_vma->vm_flags) && pte_write(pte)) { + ptep_set_wrprotect(src_mm, addr, src_pte); + pte = pte_wrprotect(pte); + } + + /* If it's a shared mapping, mark it clean in the child. */ + if (src_vma->vm_flags & VM_SHARED) + pte = pte_mkclean(pte); + pte = pte_mkold(pte); + + if (!userfaultfd_wp(dst_vma)) + pte = pte_clear_uffd_wp(pte); + + set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); +} + /* * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page * is required to copy this pte. @@ -939,16 +962,16 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, struct folio **prealloc) { - struct mm_struct *src_mm = src_vma->vm_mm; - unsigned long vm_flags = src_vma->vm_flags; pte_t pte = ptep_get(src_pte); struct page *page; struct folio *folio; page = vm_normal_page(src_vma, addr, pte); - if (page) - folio = page_folio(page); - if (page && folio_test_anon(folio)) { + if (unlikely(!page)) + goto copy_pte; + + folio = page_folio(page); + if (folio_test_anon(folio)) { /* * If this page may have been pinned by the parent process, * copy the page immediately for the child so that we'll always @@ -963,34 +986,15 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, addr, rss, prealloc, page); } rss[MM_ANONPAGES]++; - } else if (page) { + VM_WARN_ON_FOLIO(PageAnonExclusive(page), folio); + } else { folio_get(folio); folio_dup_file_rmap_pte(folio, page); rss[mm_counter_file(page)]++; } - /* - * If it's a COW mapping, write protect it both - * in the parent and the child - */ - if (is_cow_mapping(vm_flags) && pte_write(pte)) { - ptep_set_wrprotect(src_mm, addr, src_pte); - pte = pte_wrprotect(pte); - } - VM_BUG_ON(page && folio_test_anon(folio) && PageAnonExclusive(page)); - - /* - * If it's a shared mapping, mark it clean in - * the child - */ - if (vm_flags & VM_SHARED) - pte = pte_mkclean(pte); - pte = pte_mkold(pte); - - if (!userfaultfd_wp(dst_vma)) - pte = pte_clear_uffd_wp(pte); - - set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); +copy_pte: + __copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, pte, addr); return 0; }