[PATCH 1/2] mm: add locked parameter to get_user_pages_remote()
Michal Hocko
mhocko at kernel.org
Thu Oct 27 10:55:28 UTC 2016
On Thu 27-10-16 10:51:40, Lorenzo Stoakes wrote:
> This patch adds a int *locked parameter to get_user_pages_remote() to allow
> VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked().
>
> Taking into account the previous adjustments to get_user_pages*() functions
> allowing for the passing of gup_flags, we are now in a position where
> __get_user_pages_unlocked() need only be exported for his ability to allow
> VM_FAULT_RETRY behaviour, this adjustment allows us to subsequently unexport
> __get_user_pages_unlocked() as well as allowing for future flexibility in the
> use of get_user_pages_remote().
I would also add that this shouldn't introduce any functional change.
> Signed-off-by: Lorenzo Stoakes <lstoakes at gmail.com>
Acked-by: Michal Hocko <mhocko at suse.com>
> ---
> drivers/gpu/drm/etnaviv/etnaviv_gem.c | 2 +-
> drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
> drivers/infiniband/core/umem_odp.c | 2 +-
> fs/exec.c | 2 +-
> include/linux/mm.h | 2 +-
> kernel/events/uprobes.c | 4 ++--
> mm/gup.c | 12 ++++++++----
> mm/memory.c | 2 +-
> security/tomoyo/domain.c | 2 +-
> 9 files changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> index 0370b84..0c69a97f 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> @@ -763,7 +763,7 @@ static struct page **etnaviv_gem_userptr_do_get_pages(
> down_read(&mm->mmap_sem);
> while (pinned < npages) {
> ret = get_user_pages_remote(task, mm, ptr, npages - pinned,
> - flags, pvec + pinned, NULL);
> + flags, pvec + pinned, NULL, NULL);
> if (ret < 0)
> break;
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
> index c6f780f..836b525 100644
> --- a/drivers/gpu/drm/i915/i915_gem_userptr.c
> +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
> @@ -522,7 +522,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
> obj->userptr.ptr + pinned * PAGE_SIZE,
> npages - pinned,
> flags,
> - pvec + pinned, NULL);
> + pvec + pinned, NULL, NULL);
> if (ret < 0)
> break;
>
> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
> index 1f0fe32..6b079a3 100644
> --- a/drivers/infiniband/core/umem_odp.c
> +++ b/drivers/infiniband/core/umem_odp.c
> @@ -578,7 +578,7 @@ int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt,
> */
> npages = get_user_pages_remote(owning_process, owning_mm,
> user_virt, gup_num_pages,
> - flags, local_page_list, NULL);
> + flags, local_page_list, NULL, NULL);
> up_read(&owning_mm->mmap_sem);
>
> if (npages < 0)
> diff --git a/fs/exec.c b/fs/exec.c
> index 4e497b9..2cf049d 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -209,7 +209,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
> * doing the exec and bprm->mm is the new process's mm.
> */
> ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags,
> - &page, NULL);
> + &page, NULL, NULL);
> if (ret <= 0)
> return NULL;
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index a92c8d7..cc15445 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1274,7 +1274,7 @@ extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
> long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
> unsigned long start, unsigned long nr_pages,
> unsigned int gup_flags, struct page **pages,
> - struct vm_area_struct **vmas);
> + struct vm_area_struct **vmas, int *locked);
> long get_user_pages(unsigned long start, unsigned long nr_pages,
> unsigned int gup_flags, struct page **pages,
> struct vm_area_struct **vmas);
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index f9ec9ad..215871b 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -301,7 +301,7 @@ int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr,
> retry:
> /* Read the page with vaddr into memory */
> ret = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &old_page,
> - &vma);
> + &vma, NULL);
> if (ret <= 0)
> return ret;
>
> @@ -1712,7 +1712,7 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
> * essentially a kernel access to the memory.
> */
> result = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &page,
> - NULL);
> + NULL, NULL);
> if (result < 0)
> return result;
>
> diff --git a/mm/gup.c b/mm/gup.c
> index ec4f827..0567851 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -920,6 +920,9 @@ EXPORT_SYMBOL(get_user_pages_unlocked);
> * 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.
> *
> * Returns number of pages pinned. This may be fewer than the number
> * requested. If nr_pages is 0 or negative, returns 0. If no pages
> @@ -963,10 +966,10 @@ EXPORT_SYMBOL(get_user_pages_unlocked);
> long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
> unsigned long start, unsigned long nr_pages,
> unsigned int gup_flags, struct page **pages,
> - struct vm_area_struct **vmas)
> + struct vm_area_struct **vmas, int *locked)
> {
> return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas,
> - NULL, false,
> + locked, true,
> gup_flags | FOLL_TOUCH | FOLL_REMOTE);
> }
> EXPORT_SYMBOL(get_user_pages_remote);
> @@ -974,8 +977,9 @@ EXPORT_SYMBOL(get_user_pages_remote);
> /*
> * This is the same as get_user_pages_remote(), just with a
> * less-flexible calling convention where we assume that the task
> - * and mm being operated on are the current task's. We also
> - * obviously don't pass FOLL_REMOTE in here.
> + * and mm being operated on are the current task's and don't allow
> + * passing of a locked parameter. We also obviously don't pass
> + * FOLL_REMOTE in here.
> */
> long get_user_pages(unsigned long start, unsigned long nr_pages,
> unsigned int gup_flags, struct page **pages,
> diff --git a/mm/memory.c b/mm/memory.c
> index e18c57b..2f3949b 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3883,7 +3883,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
> struct page *page = NULL;
>
> ret = get_user_pages_remote(tsk, mm, addr, 1,
> - gup_flags, &page, &vma);
> + gup_flags, &page, &vma, NULL);
> if (ret <= 0) {
> #ifndef CONFIG_HAVE_IOREMAP_PROT
> break;
> diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
> index 682b73a..838ffa7 100644
> --- a/security/tomoyo/domain.c
> +++ b/security/tomoyo/domain.c
> @@ -881,7 +881,7 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
> * the execve().
> */
> if (get_user_pages_remote(current, bprm->mm, pos, 1,
> - FOLL_FORCE, &page, NULL) <= 0)
> + FOLL_FORCE, &page, NULL, NULL) <= 0)
> return false;
> #else
> page = bprm->page[pos / PAGE_SIZE];
> --
> 2.10.1
--
Michal Hocko
SUSE Labs
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