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Sat, 15 Apr 2023 05:09:29 -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 v3 4/7] mm/gup: introduce the FOLL_SAME_FILE GUP flag Date: Sat, 15 Apr 2023 13:09:27 +0100 Message-Id: <2feedd2bad6fd1ec4bc4639f9d9012c5ae2faf1f.1681558407.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-Queue-Id: CF3638000C X-Stat-Signature: uwufp6kz3dd8dzxs6ddztkmjkpjnt4uc X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1681560571-465074 X-HE-Meta: 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 wLzQZnBc P6y5m0VvP0RcOFoIqf06/rNaPz9HxaqwiWXwSCBdMGKzNcxyLVx1Flh2OGFO5vPh35hjdHTsFyD6pfnk9bJWzHMV7k2J7VIO/UbbAEdzGBQPVpIGxS7PZFotEWdOWCqMp0DZq2VlXj5iMIYlvt+0RW5fsJTxa2SuP2EbmyhIurYN9Nv0Esfi3Mqe68QPjGVWqgS9vhiP50ZMDHjdYEIeMbi2IvP5wO3PCYZqWTu4S3R8PWcPNZNkka2BCx2fETadqL4HWASuK5WLHPvDnFJKawDrkUYmFJog80KWyInB9qwAgVNPhlm6SLaqDuwwdVZx7VAa8QzjVLZOXFGznfjA+4sJfOIDdWFBRtBw58X8C7Mi7iM1jiNnjfnv38NbrtYnAqofNEm535LC+IKY7BcTitGyV5tfx9rBGlft6WD+pqQMpeBkQxubUuBeU/6E4Tit8YN/3kDjSACUgbaoMYbNWafXTCky+kUJUda6UnRj3ocoDB4w= 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