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Fri, 07 Jul 2023 14:55:48 -0700 (PDT) Date: Fri, 7 Jul 2023 14:55:35 -0700 In-Reply-To: <20230707215540.2324998-1-axelrasmussen@google.com> Mime-Version: 1.0 References: <20230707215540.2324998-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog Message-ID: <20230707215540.2324998-4-axelrasmussen@google.com> Subject: [PATCH v4 3/8] mm: userfaultfd: extract file size check out into a helper From: Axel Rasmussen To: Alexander Viro , Andrew Morton , Brian Geffon , Christian Brauner , David Hildenbrand , Gaosheng Cui , Huang Ying , Hugh Dickins , James Houghton , "Jan Alexander Steffens (heftig)" , Jiaqi Yan , Jonathan Corbet , Kefeng Wang , "Liam R. Howlett" , Miaohe Lin , Mike Kravetz , "Mike Rapoport (IBM)" , Muchun Song , Nadav Amit , Naoya Horiguchi , Peter Xu , Ryan Roberts , Shuah Khan , Suleiman Souhlal , Suren Baghdasaryan , "T.J. Alumbaugh" , Yu Zhao , ZhangPeng Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Axel Rasmussen X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: EC04014000E X-Stat-Signature: 59666b8496qr8uw5bftqr9kghjdyzgak X-Rspam-User: X-HE-Tag: 1688766949-668845 X-HE-Meta: U2FsdGVkX19XpldF7AZKV318Ubw7QW11LjC4v9UlTAFqB+dTSC1oTt2QTEuxaAudJ2+PQMyD+aWOvLgKfH4R1xdQUDu8mbxVhTn8IjTdd8Kmq25P6TjSLm+w8sKyna2Np19WwXIea6Ah7crYCEBbICOVc2U5r0KXVduEGL7BawmrL5VOj6EwhrSKUMjijxbnMsRFp2vhc6lRE6+MqiMSMxFLdpvKqFFvT/hYCZD1DnfTKHpqb2r8JGMo0kb7T5uda9iM3oDdbkGTVRK75vohK95dRxYFuGtdzLHlyDEObsBltE9jFAlpBCZGQbAbkAPc44+KLfTWSB1z66it9hc/5UlnMy+rGUwrwQHGXm69kVOWhF1YFoblAPGuj/70clyd03QWnUW4hYkSOLU5lNPS491MQ447GieWJ3T3QkYEuzUbEawgrGgijWi5tcKGcL62QxgRz2WLsFeyiJVyKeP8oVp/Fg6ifuQiaq2y1yIRO3Lhof3OjE126RfkN9F4fE1rpYj0t2CSU3oRJJzBgn4qtjRSTPZDoVtO3LZ2rY2CiE3QN0ni2ZWZuweFvZQSb9rWzTXcEda0XZ4/SR1ziOAgqG1vdtHp6wX+dzaX6in/2vqU8QuWtbjWIsObioaObx1jOl3R0NQJ0b9xCjnMJ9DxPT+5TqkuOg4YuCAVjMzwYQShJIxhWQ51mYyuXYYhth6Liu5u1ssnWj5t9uaBXTBaIwn8nEW8pIjswXQRDSqeOELaZgBMEF/cvtioFhIbyApSNch6DchPFWWLkv+zJNA6Des73lzIbS+qA2gUgPZRrxAptf2vienc4ocWKcK5s+toty3Z4mJe4Gn69vVM24IH0exX4vKkB6gaGgCcr1CGfKZeUEyWPYWfRaW/xELUObdGM4eqnbAtEttU5mBpCejvr/rnInjXT8waEFwGR4JjReXbio2U1R3lviPmwoLaxrujBSPYwH/TKuO5ohWhYHh IKFuXwRT 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 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: This code is already duplicated twice, and UFFDIO_POISON will do the same check a third time. So, it's worth extracting into a helper to save repetitive lines of code. Reviewed-by: Peter Xu Signed-off-by: Axel Rasmussen --- mm/userfaultfd.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index a2bf37ee276d..4244ca7ee903 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -45,6 +45,22 @@ struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, return dst_vma; } +/* Check if dst_addr is outside of file's size. Must be called with ptl held. */ +static bool mfill_file_over_size(struct vm_area_struct *dst_vma, + unsigned long dst_addr) +{ + struct inode *inode; + pgoff_t offset, max_off; + + if (!dst_vma->vm_file) + return false; + + inode = dst_vma->vm_file->f_inode; + offset = linear_page_index(dst_vma, dst_addr); + max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); + return offset >= max_off; +} + /* * Install PTEs, to map dst_addr (within dst_vma) to page. * @@ -64,8 +80,6 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, bool page_in_cache = page_mapping(page); spinlock_t *ptl; struct folio *folio; - struct inode *inode; - pgoff_t offset, max_off; _dst_pte = mk_pte(page, dst_vma->vm_page_prot); _dst_pte = pte_mkdirty(_dst_pte); @@ -81,14 +95,9 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, if (!dst_pte) goto out; - if (vma_is_shmem(dst_vma)) { - /* serialize against truncate with the page table lock */ - inode = dst_vma->vm_file->f_inode; - offset = linear_page_index(dst_vma, dst_addr); - max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); + if (mfill_file_over_size(dst_vma, dst_addr)) { ret = -EFAULT; - if (unlikely(offset >= max_off)) - goto out_unlock; + goto out_unlock; } ret = -EEXIST; @@ -211,8 +220,6 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd, pte_t _dst_pte, *dst_pte; spinlock_t *ptl; int ret; - pgoff_t offset, max_off; - struct inode *inode; _dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), dst_vma->vm_page_prot)); @@ -220,14 +227,9 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd, dst_pte = pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl); if (!dst_pte) goto out; - if (dst_vma->vm_file) { - /* the shmem MAP_PRIVATE case requires checking the i_size */ - inode = dst_vma->vm_file->f_inode; - offset = linear_page_index(dst_vma, dst_addr); - max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); + if (mfill_file_over_size(dst_vma, dst_addr)) { ret = -EFAULT; - if (unlikely(offset >= max_off)) - goto out_unlock; + goto out_unlock; } ret = -EEXIST; if (!pte_none(ptep_get(dst_pte)))