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[86.156.84.164]) by smtp.googlemail.com with ESMTPSA id u6-20020a5d6ac6000000b002f2789d1bcfsm4546827wrw.21.2023.04.14.16.27.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Apr 2023 16:27:45 -0700 (PDT) From: Lorenzo Stoakes To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton Cc: Matthew Wilcox , David Hildenbrand , Lorenzo Stoakes Subject: [PATCH 4/7] mm/gup: introduce the FOLL_SAME_FILE GUP flag Date: Sat, 15 Apr 2023 00:27:40 +0100 Message-Id: <7ed66bd5243f7535030e0fa6a8a94b76dc5033f1.1681508038.git.lstoakes@gmail.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 7B46214000B X-Rspam-User: X-Stat-Signature: tquc3sxrunfpen7o53hfabhtiedqysui X-HE-Tag: 1681514867-995700 X-HE-Meta: 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 0S83xe3K 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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 flag causes GUP to assert that all VMAs within the input range possess the same vma->vm_file. If not, the operation fails. This is part of a patch series which eliminates the vmas parameter from the GUP API, implementing the one remaining assertion within the entire kernel that requires access to the VMAs associated with a GUP range. Signed-off-by: Lorenzo Stoakes --- include/linux/mm_types.h | 2 ++ mm/gup.c | 16 ++++++++++++---- 2 files changed, 14 insertions(+), 4 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 3fc9e680f174..84d1aec9dbab 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1185,6 +1185,8 @@ enum { FOLL_PCI_P2PDMA = 1 << 10, /* allow interrupts from generic signals */ FOLL_INTERRUPTIBLE = 1 << 11, + /* assert that the range spans VMAs with the same vma->vm_file */ + FOLL_SAME_FILE = 1 << 12, /* See also internal only FOLL flags in mm/internal.h */ }; diff --git a/mm/gup.c b/mm/gup.c index 9440aa54c741..3954ce499a4a 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -959,7 +959,8 @@ static int faultin_page(struct vm_area_struct *vma, return 0; } -static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) +static int check_vma_flags(struct vm_area_struct *vma, struct file *file, + unsigned long gup_flags) { vm_flags_t vm_flags = vma->vm_flags; int write = (gup_flags & FOLL_WRITE); @@ -968,7 +969,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) if (vm_flags & (VM_IO | VM_PFNMAP)) return -EFAULT; - if (gup_flags & FOLL_ANON && !vma_is_anonymous(vma)) + if ((gup_flags & FOLL_ANON) && !vma_is_anonymous(vma)) return -EFAULT; if ((gup_flags & FOLL_LONGTERM) && vma_is_fsdax(vma)) @@ -977,6 +978,9 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) if (vma_is_secretmem(vma)) return -EFAULT; + if ((gup_flags & FOLL_SAME_FILE) && vma->vm_file != file) + return -EFAULT; + if (write) { if (!(vm_flags & VM_WRITE)) { if (!(gup_flags & FOLL_FORCE)) @@ -1081,6 +1085,7 @@ static long __get_user_pages(struct mm_struct *mm, long ret = 0, i = 0; struct vm_area_struct *vma = NULL; struct follow_page_context ctx = { NULL }; + struct file *file = NULL; if (!nr_pages) return 0; @@ -1111,10 +1116,13 @@ static long __get_user_pages(struct mm_struct *mm, ret = -EFAULT; goto out; } - ret = check_vma_flags(vma, gup_flags); + ret = check_vma_flags(vma, i == 0 ? vma->vm_file : file, + gup_flags); if (ret) goto out; + file = vma->vm_file; + if (is_vm_hugetlb_page(vma)) { i = follow_hugetlb_page(mm, vma, pages, vmas, &start, &nr_pages, i, @@ -1595,7 +1603,7 @@ long faultin_vma_page_range(struct vm_area_struct *vma, unsigned long start, * We want to report -EINVAL instead of -EFAULT for any permission * problems or incompatible mappings. */ - if (check_vma_flags(vma, gup_flags)) + if (check_vma_flags(vma, vma->vm_file, gup_flags)) return -EINVAL; ret = __get_user_pages(mm, start, nr_pages, gup_flags, -- 2.40.0