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Hallyn" , Paolo Bonzini , Lorenzo Stoakes Subject: [PATCH v2 3/7] mm/gup: remove vmas parameter from get_user_pages_remote() Date: Sat, 15 Apr 2023 10:08:34 +0100 Message-Id: <631001ecc556c5e348ff4f47719334c31f7bd592.1681547405.git.lstoakes@gmail.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The only instances of get_user_pages_remote() invocations which used the vmas parameter were for a single page which can instead simply look up the VMA directly. In particular:- - __update_ref_ctr() looked up the VMA but did nothing with it so we simply remove it. - __access_remote_vm() was already using vma_lookup() when the original lookup failed so by doing the lookup directly this also de-duplicates the code. This forms part of a broader set of patches intended to eliminate the vmas parameter altogether. Signed-off-by: Lorenzo Stoakes --- arch/arm64/kernel/mte.c | 7 ++++--- arch/s390/kvm/interrupt.c | 2 +- fs/exec.c | 2 +- include/linux/mm.h | 2 +- kernel/events/uprobes.c | 12 +++++++----- mm/gup.c | 12 ++++-------- mm/memory.c | 9 +++++---- mm/rmap.c | 2 +- security/tomoyo/domain.c | 2 +- virt/kvm/async_pf.c | 3 +-- 10 files changed, 26 insertions(+), 27 deletions(-) diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index f5bcb0dc6267..d43a744d7919 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -419,7 +419,6 @@ long get_mte_ctrl(struct task_struct *task) static int __access_remote_tags(struct mm_struct *mm, unsigned long addr, struct iovec *kiov, unsigned int gup_flags) { - struct vm_area_struct *vma; void __user *buf = kiov->iov_base; size_t len = kiov->iov_len; int ret; @@ -432,12 +431,13 @@ static int __access_remote_tags(struct mm_struct *mm, unsigned long addr, return -EIO; while (len) { + struct vm_area_struct *vma; unsigned long tags, offset; void *maddr; struct page *page = NULL; ret = get_user_pages_remote(mm, addr, 1, gup_flags, &page, - &vma, NULL); + NULL); if (ret <= 0) break; @@ -448,7 +448,8 @@ static int __access_remote_tags(struct mm_struct *mm, unsigned long addr, * would cause the existing tags to be cleared if the page * was never mapped with PROT_MTE. */ - if (!(vma->vm_flags & VM_MTE)) { + vma = vma_lookup(mm, addr); + if (!vma || !(vma->vm_flags & VM_MTE)) { ret = -EOPNOTSUPP; put_page(page); break; diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 9250fde1f97d..c19d0cb7d2f2 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2777,7 +2777,7 @@ static struct page *get_map_page(struct kvm *kvm, u64 uaddr) mmap_read_lock(kvm->mm); get_user_pages_remote(kvm->mm, uaddr, 1, FOLL_WRITE, - &page, NULL, NULL); + &page, NULL); mmap_read_unlock(kvm->mm); return page; } diff --git a/fs/exec.c b/fs/exec.c index 87cf3a2f0e9a..d8d48ee15aac 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -219,7 +219,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, */ mmap_read_lock(bprm->mm); ret = get_user_pages_remote(bprm->mm, pos, 1, gup_flags, - &page, NULL, NULL); + &page, NULL); mmap_read_unlock(bprm->mm); if (ret <= 0) return NULL; diff --git a/include/linux/mm.h b/include/linux/mm.h index ec9875c59f6d..1bfe73a2b6d3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2374,7 +2374,7 @@ extern int __access_remote_vm(struct mm_struct *mm, unsigned long addr, long get_user_pages_remote(struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas, int *locked); + int *locked); long pin_user_pages_remote(struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 59887c69d54c..b21993cd2dcc 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -365,7 +365,6 @@ __update_ref_ctr(struct mm_struct *mm, unsigned long vaddr, short d) { void *kaddr; struct page *page; - struct vm_area_struct *vma; int ret; short *ptr; @@ -373,7 +372,7 @@ __update_ref_ctr(struct mm_struct *mm, unsigned long vaddr, short d) return -EINVAL; ret = get_user_pages_remote(mm, vaddr, 1, - FOLL_WRITE, &page, &vma, NULL); + FOLL_WRITE, &page, NULL); if (unlikely(ret <= 0)) { /* * We are asking for 1 page. If get_user_pages_remote() fails, @@ -475,10 +474,14 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, gup_flags |= FOLL_SPLIT_PMD; /* Read the page with vaddr into memory */ ret = get_user_pages_remote(mm, vaddr, 1, gup_flags, - &old_page, &vma, NULL); + &old_page, NULL); if (ret <= 0) return ret; + vma = vma_lookup(mm, vaddr); + if (!vma) + goto put_old; + ret = verify_opcode(old_page, vaddr, &opcode); if (ret <= 0) goto put_old; @@ -2027,8 +2030,7 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr) * but we treat this as a 'remote' access since it is * essentially a kernel access to the memory. */ - result = get_user_pages_remote(mm, vaddr, 1, FOLL_FORCE, &page, - NULL, NULL); + result = get_user_pages_remote(mm, vaddr, 1, FOLL_FORCE, &page, NULL); if (result < 0) return result; diff --git a/mm/gup.c b/mm/gup.c index 931c805bc32b..9440aa54c741 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2165,8 +2165,6 @@ static bool is_valid_gup_args(struct page **pages, struct vm_area_struct **vmas, * @pages: array that receives pointers to the pages pinned. * Should be at least nr_pages long. Or NULL, if caller * only intends to ensure the pages are faulted in. - * @vmas: array of pointers to vmas corresponding to each page. - * Or NULL if the caller does not require them. * @locked: pointer to lock flag indicating whether lock is held and * subsequently whether VM_FAULT_RETRY functionality can be * utilised. Lock must initially be held. @@ -2181,8 +2179,6 @@ static bool is_valid_gup_args(struct page **pages, struct vm_area_struct **vmas, * * The caller is responsible for releasing returned @pages, via put_page(). * - * @vmas are valid only as long as mmap_lock is held. - * * Must be called with mmap_lock held for read or write. * * get_user_pages_remote walks a process's page tables and takes a reference @@ -2219,15 +2215,15 @@ static bool is_valid_gup_args(struct page **pages, struct vm_area_struct **vmas, long get_user_pages_remote(struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas, int *locked) + int *locked) { int local_locked = 1; - if (!is_valid_gup_args(pages, vmas, locked, &gup_flags, + if (!is_valid_gup_args(pages, NULL, locked, &gup_flags, FOLL_TOUCH | FOLL_REMOTE)) return -EINVAL; - return __get_user_pages_locked(mm, start, nr_pages, pages, vmas, + return __get_user_pages_locked(mm, start, nr_pages, pages, NULL, locked ? locked : &local_locked, gup_flags); } @@ -2237,7 +2233,7 @@ EXPORT_SYMBOL(get_user_pages_remote); long get_user_pages_remote(struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas, int *locked) + int *locked) { return 0; } diff --git a/mm/memory.c b/mm/memory.c index 8ddb10199e8d..913e693322f2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5591,7 +5591,9 @@ int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, struct page *page = NULL; ret = get_user_pages_remote(mm, addr, 1, - gup_flags, &page, &vma, NULL); + gup_flags, &page, NULL); + vma = vma_lookup(mm, addr); + if (ret <= 0) { #ifndef CONFIG_HAVE_IOREMAP_PROT break; @@ -5600,7 +5602,6 @@ int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, * Check if this is a VM_IO | VM_PFNMAP VMA, which * we can access using slightly different code. */ - vma = vma_lookup(mm, addr); if (!vma) break; if (vma->vm_ops && vma->vm_ops->access) @@ -5617,11 +5618,11 @@ int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, bytes = PAGE_SIZE-offset; maddr = kmap(page); - if (write) { + if (write && vma) { copy_to_user_page(vma, page, addr, maddr + offset, buf, bytes); set_page_dirty_lock(page); - } else { + } else if (vma) { copy_from_user_page(vma, page, addr, buf, maddr + offset, bytes); } diff --git a/mm/rmap.c b/mm/rmap.c index ba901c416785..756ea8a9bb90 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2324,7 +2324,7 @@ int make_device_exclusive_range(struct mm_struct *mm, unsigned long start, npages = get_user_pages_remote(mm, start, npages, FOLL_GET | FOLL_WRITE | FOLL_SPLIT_PMD, - pages, NULL, NULL); + pages, NULL); if (npages < 0) return npages; diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c index 31af29f669d2..ac20c0bdff9d 100644 --- a/security/tomoyo/domain.c +++ b/security/tomoyo/domain.c @@ -916,7 +916,7 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos, */ mmap_read_lock(bprm->mm); ret = get_user_pages_remote(bprm->mm, pos, 1, - FOLL_FORCE, &page, NULL, NULL); + FOLL_FORCE, &page, NULL); mmap_read_unlock(bprm->mm); if (ret <= 0) return false; diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index 9bfe1d6f6529..e033c79d528e 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -61,8 +61,7 @@ static void async_pf_execute(struct work_struct *work) * access remotely. */ mmap_read_lock(mm); - get_user_pages_remote(mm, addr, 1, FOLL_WRITE, NULL, NULL, - &locked); + get_user_pages_remote(mm, addr, 1, FOLL_WRITE, NULL, &locked); if (locked) mmap_read_unlock(mm);