* [PATCH 0/2] mm: unexport __get_user_pages_unlocked() @ 2016-10-27 9:51 Lorenzo Stoakes 2016-10-27 9:51 ` [PATCH 1/2] mm: add locked parameter to get_user_pages_remote() Lorenzo Stoakes ` (2 more replies) 0 siblings, 3 replies; 7+ messages in thread From: Lorenzo Stoakes @ 2016-10-27 9:51 UTC (permalink / raw) To: linux-mm Cc: Michal Hocko, Linus Torvalds, Jan Kara, Hugh Dickins, Dave Hansen, Rik van Riel, Mel Gorman, Andrew Morton, Paolo Bonzini, Radim Krčmář, kvm, linux-kernel, linux-security-module, linux-rdma, dri-devel, linux-fsdevel This patch series continues the cleanup of get_user_pages*() functions taking advantage of the fact we can now pass gup_flags as we please. It firstly adds an additional 'locked' parameter to get_user_pages_remote() to allow for its callers to utilise VM_FAULT_RETRY functionality. This is necessary as the invocation of __get_user_pages_unlocked() in process_vm_rw_single_vec() makes use of this and no other existing higher level function would allow it to do so. Secondly existing callers of __get_user_pages_unlocked() are replaced with the appropriate higher-level replacement - get_user_pages_unlocked() if the current task and memory descriptor are referenced, or get_user_pages_remote() if other task/memory descriptors are referenced (having acquiring mmap_sem.) Lorenzo Stoakes (2): mm: add locked parameter to get_user_pages_remote() mm: unexport __get_user_pages_unlocked() 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 | 5 +---- kernel/events/uprobes.c | 4 ++-- mm/gup.c | 20 ++++++++++++-------- mm/memory.c | 2 +- mm/nommu.c | 7 +++---- mm/process_vm_access.c | 12 ++++++++---- security/tomoyo/domain.c | 2 +- virt/kvm/async_pf.c | 10 +++++++--- virt/kvm/kvm_main.c | 5 ++--- 13 files changed, 41 insertions(+), 34 deletions(-) ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH 1/2] mm: add locked parameter to get_user_pages_remote() 2016-10-27 9:51 [PATCH 0/2] mm: unexport __get_user_pages_unlocked() Lorenzo Stoakes @ 2016-10-27 9:51 ` Lorenzo Stoakes 2016-10-27 10:55 ` Michal Hocko 2016-10-27 9:51 ` [PATCH 2/2] mm: unexport __get_user_pages_unlocked() Lorenzo Stoakes 2016-10-27 9:54 ` [PATCH 0/2] " Lorenzo Stoakes 2 siblings, 1 reply; 7+ messages in thread From: Lorenzo Stoakes @ 2016-10-27 9:51 UTC (permalink / raw) To: linux-mm Cc: Michal Hocko, Linus Torvalds, Jan Kara, Hugh Dickins, Dave Hansen, Rik van Riel, Mel Gorman, Andrew Morton, Paolo Bonzini, Radim Krčmář, kvm, linux-kernel, linux-security-module, linux-rdma, dri-devel, linux-fsdevel, Lorenzo Stoakes 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(). Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.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 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] mm: add locked parameter to get_user_pages_remote() 2016-10-27 9:51 ` [PATCH 1/2] mm: add locked parameter to get_user_pages_remote() Lorenzo Stoakes @ 2016-10-27 10:55 ` Michal Hocko 2016-10-27 10:59 ` Michal Hocko 0 siblings, 1 reply; 7+ messages in thread From: Michal Hocko @ 2016-10-27 10:55 UTC (permalink / raw) To: Lorenzo Stoakes Cc: linux-mm, Linus Torvalds, Jan Kara, Hugh Dickins, Dave Hansen, Rik van Riel, Mel Gorman, Andrew Morton, Paolo Bonzini, Radim Krčmář, kvm, linux-kernel, linux-security-module, linux-rdma, dri-devel, linux-fsdevel 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@gmail.com> Acked-by: Michal Hocko <mhocko@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 ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] mm: add locked parameter to get_user_pages_remote() 2016-10-27 10:55 ` Michal Hocko @ 2016-10-27 10:59 ` Michal Hocko 0 siblings, 0 replies; 7+ messages in thread From: Michal Hocko @ 2016-10-27 10:59 UTC (permalink / raw) To: Lorenzo Stoakes Cc: linux-mm, Linus Torvalds, Jan Kara, Hugh Dickins, Dave Hansen, Rik van Riel, Mel Gorman, Andrew Morton, Paolo Bonzini, Radim Krčmář, kvm, linux-kernel, linux-security-module, linux-rdma, dri-devel, linux-fsdevel On Thu 27-10-16 12:55:27, Michal Hocko wrote: > 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. Forgot to mention that this also opens doors to change other g_u_p_r callers to allow FAULT_RETRY logic. -- Michal Hocko SUSE Labs ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH 2/2] mm: unexport __get_user_pages_unlocked() 2016-10-27 9:51 [PATCH 0/2] mm: unexport __get_user_pages_unlocked() Lorenzo Stoakes 2016-10-27 9:51 ` [PATCH 1/2] mm: add locked parameter to get_user_pages_remote() Lorenzo Stoakes @ 2016-10-27 9:51 ` Lorenzo Stoakes 2016-10-27 10:57 ` Michal Hocko 2016-10-27 9:54 ` [PATCH 0/2] " Lorenzo Stoakes 2 siblings, 1 reply; 7+ messages in thread From: Lorenzo Stoakes @ 2016-10-27 9:51 UTC (permalink / raw) To: linux-mm Cc: Michal Hocko, Linus Torvalds, Jan Kara, Hugh Dickins, Dave Hansen, Rik van Riel, Mel Gorman, Andrew Morton, Paolo Bonzini, Radim Krčmář, kvm, linux-kernel, linux-security-module, linux-rdma, dri-devel, linux-fsdevel, Lorenzo Stoakes This patch unexports the low-level __get_user_pages_unlocked() function and replaces invocations with calls to more appropriate higher-level functions. In hva_to_pfn_slow() we are able to replace __get_user_pages_unlocked() with get_user_pages_unlocked() since we can now pass gup_flags. In async_pf_execute() and process_vm_rw_single_vec() we need to pass different tsk, mm arguments so get_user_pages_remote() is the sane replacement in these cases (having added manual acquisition and release of mmap_sem.) Additionally get_user_pages_remote() reintroduces use of the FOLL_TOUCH flag. However, this flag was originally silently dropped by 1e9877902dc7e ("mm/gup: Introduce get_user_pages_remote()"), so this appears to have been unintentional and reintroducing it is therefore not an issue. Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> --- include/linux/mm.h | 3 --- mm/gup.c | 8 ++++---- mm/nommu.c | 7 +++---- mm/process_vm_access.c | 12 ++++++++---- virt/kvm/async_pf.c | 10 +++++++--- virt/kvm/kvm_main.c | 5 ++--- 6 files changed, 24 insertions(+), 21 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index cc15445..7b2d14e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1280,9 +1280,6 @@ long get_user_pages(unsigned long start, unsigned long nr_pages, struct vm_area_struct **vmas); long get_user_pages_locked(unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, int *locked); -long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, - struct page **pages, unsigned int gup_flags); long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags); int get_user_pages_fast(unsigned long start, int nr_pages, int write, diff --git a/mm/gup.c b/mm/gup.c index 0567851..8028af1 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -866,9 +866,10 @@ EXPORT_SYMBOL(get_user_pages_locked); * caller if required (just like with __get_user_pages). "FOLL_GET" * is set implicitly if "pages" is non-NULL. */ -__always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, - struct page **pages, unsigned int gup_flags) +static __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, + struct mm_struct *mm, unsigned long start, + unsigned long nr_pages, struct page **pages, + unsigned int gup_flags) { long ret; int locked = 1; @@ -880,7 +881,6 @@ __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct m up_read(&mm->mmap_sem); return ret; } -EXPORT_SYMBOL(__get_user_pages_unlocked); /* * get_user_pages_unlocked() is suitable to replace the form: diff --git a/mm/nommu.c b/mm/nommu.c index 8b8faaf..669437b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -176,9 +176,9 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, } EXPORT_SYMBOL(get_user_pages_locked); -long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, - struct page **pages, unsigned int gup_flags) +static long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, unsigned long nr_pages, + struct page **pages, unsigned int gup_flags) { long ret; down_read(&mm->mmap_sem); @@ -187,7 +187,6 @@ long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, up_read(&mm->mmap_sem); return ret; } -EXPORT_SYMBOL(__get_user_pages_unlocked); long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags) diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index be8dc8d..84d0c7e 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -88,7 +88,7 @@ static int process_vm_rw_single_vec(unsigned long addr, ssize_t rc = 0; unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES / sizeof(struct pages *); - unsigned int flags = FOLL_REMOTE; + unsigned int flags = 0; /* Work out address and page range required */ if (len == 0) @@ -100,15 +100,19 @@ static int process_vm_rw_single_vec(unsigned long addr, while (!rc && nr_pages && iov_iter_count(iter)) { int pages = min(nr_pages, max_pages_per_loop); + int locked = 1; size_t bytes; /* * Get the pages we're interested in. We must - * add FOLL_REMOTE because task/mm might not + * access remotely because task/mm might not * current/current->mm */ - pages = __get_user_pages_unlocked(task, mm, pa, pages, - process_pages, flags); + down_read(&mm->mmap_sem); + pages = get_user_pages_remote(task, mm, pa, pages, flags, + process_pages, NULL, &locked); + if (locked) + up_read(&mm->mmap_sem); if (pages <= 0) return -EFAULT; diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index 8035cc1..dab8b19 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -76,16 +76,20 @@ static void async_pf_execute(struct work_struct *work) struct kvm_vcpu *vcpu = apf->vcpu; unsigned long addr = apf->addr; gva_t gva = apf->gva; + int locked = 1; might_sleep(); /* * This work is run asynchromously to the task which owns * mm and might be done in another context, so we must - * use FOLL_REMOTE. + * access remotely. */ - __get_user_pages_unlocked(NULL, mm, addr, 1, NULL, - FOLL_WRITE | FOLL_REMOTE); + down_read(&mm->mmap_sem); + get_user_pages_remote(NULL, mm, addr, 1, FOLL_WRITE, NULL, NULL, + &locked); + if (locked) + up_read(&mm->mmap_sem); kvm_async_page_present_sync(vcpu, apf); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2907b7b..c45d951 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1415,13 +1415,12 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault, npages = get_user_page_nowait(addr, write_fault, page); up_read(¤t->mm->mmap_sem); } else { - unsigned int flags = FOLL_TOUCH | FOLL_HWPOISON; + unsigned int flags = FOLL_HWPOISON; if (write_fault) flags |= FOLL_WRITE; - npages = __get_user_pages_unlocked(current, current->mm, addr, 1, - page, flags); + npages = get_user_pages_unlocked(addr, 1, page, flags); } if (npages != 1) return npages; -- 2.10.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] mm: unexport __get_user_pages_unlocked() 2016-10-27 9:51 ` [PATCH 2/2] mm: unexport __get_user_pages_unlocked() Lorenzo Stoakes @ 2016-10-27 10:57 ` Michal Hocko 0 siblings, 0 replies; 7+ messages in thread From: Michal Hocko @ 2016-10-27 10:57 UTC (permalink / raw) To: Lorenzo Stoakes Cc: linux-mm, Linus Torvalds, Jan Kara, Hugh Dickins, Dave Hansen, Rik van Riel, Mel Gorman, Andrew Morton, Paolo Bonzini, Radim Krčmář, kvm, linux-kernel, linux-security-module, linux-rdma, dri-devel, linux-fsdevel On Thu 27-10-16 10:51:41, Lorenzo Stoakes wrote: > This patch unexports the low-level __get_user_pages_unlocked() function and > replaces invocations with calls to more appropriate higher-level functions. > > In hva_to_pfn_slow() we are able to replace __get_user_pages_unlocked() with > get_user_pages_unlocked() since we can now pass gup_flags. > > In async_pf_execute() and process_vm_rw_single_vec() we need to pass different > tsk, mm arguments so get_user_pages_remote() is the sane replacement in these > cases (having added manual acquisition and release of mmap_sem.) > > Additionally get_user_pages_remote() reintroduces use of the FOLL_TOUCH > flag. However, this flag was originally silently dropped by 1e9877902dc7e > ("mm/gup: Introduce get_user_pages_remote()"), so this appears to have been > unintentional and reintroducing it is therefore not an issue. Looks good to me. > Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> > --- > include/linux/mm.h | 3 --- > mm/gup.c | 8 ++++---- > mm/nommu.c | 7 +++---- > mm/process_vm_access.c | 12 ++++++++---- > virt/kvm/async_pf.c | 10 +++++++--- > virt/kvm/kvm_main.c | 5 ++--- > 6 files changed, 24 insertions(+), 21 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index cc15445..7b2d14e 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1280,9 +1280,6 @@ long get_user_pages(unsigned long start, unsigned long nr_pages, > struct vm_area_struct **vmas); > long get_user_pages_locked(unsigned long start, unsigned long nr_pages, > unsigned int gup_flags, struct page **pages, int *locked); > -long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, > - unsigned long start, unsigned long nr_pages, > - struct page **pages, unsigned int gup_flags); > long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, > struct page **pages, unsigned int gup_flags); > int get_user_pages_fast(unsigned long start, int nr_pages, int write, > diff --git a/mm/gup.c b/mm/gup.c > index 0567851..8028af1 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -866,9 +866,10 @@ EXPORT_SYMBOL(get_user_pages_locked); > * caller if required (just like with __get_user_pages). "FOLL_GET" > * is set implicitly if "pages" is non-NULL. > */ > -__always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, > - unsigned long start, unsigned long nr_pages, > - struct page **pages, unsigned int gup_flags) > +static __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, > + struct mm_struct *mm, unsigned long start, > + unsigned long nr_pages, struct page **pages, > + unsigned int gup_flags) > { > long ret; > int locked = 1; > @@ -880,7 +881,6 @@ __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct m > up_read(&mm->mmap_sem); > return ret; > } > -EXPORT_SYMBOL(__get_user_pages_unlocked); > > /* > * get_user_pages_unlocked() is suitable to replace the form: > diff --git a/mm/nommu.c b/mm/nommu.c > index 8b8faaf..669437b 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -176,9 +176,9 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, > } > EXPORT_SYMBOL(get_user_pages_locked); > > -long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, > - unsigned long start, unsigned long nr_pages, > - struct page **pages, unsigned int gup_flags) > +static long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, > + unsigned long start, unsigned long nr_pages, > + struct page **pages, unsigned int gup_flags) > { > long ret; > down_read(&mm->mmap_sem); > @@ -187,7 +187,6 @@ long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, > up_read(&mm->mmap_sem); > return ret; > } > -EXPORT_SYMBOL(__get_user_pages_unlocked); > > long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, > struct page **pages, unsigned int gup_flags) > diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c > index be8dc8d..84d0c7e 100644 > --- a/mm/process_vm_access.c > +++ b/mm/process_vm_access.c > @@ -88,7 +88,7 @@ static int process_vm_rw_single_vec(unsigned long addr, > ssize_t rc = 0; > unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES > / sizeof(struct pages *); > - unsigned int flags = FOLL_REMOTE; > + unsigned int flags = 0; > > /* Work out address and page range required */ > if (len == 0) > @@ -100,15 +100,19 @@ static int process_vm_rw_single_vec(unsigned long addr, > > while (!rc && nr_pages && iov_iter_count(iter)) { > int pages = min(nr_pages, max_pages_per_loop); > + int locked = 1; > size_t bytes; > > /* > * Get the pages we're interested in. We must > - * add FOLL_REMOTE because task/mm might not > + * access remotely because task/mm might not > * current/current->mm > */ > - pages = __get_user_pages_unlocked(task, mm, pa, pages, > - process_pages, flags); > + down_read(&mm->mmap_sem); > + pages = get_user_pages_remote(task, mm, pa, pages, flags, > + process_pages, NULL, &locked); > + if (locked) > + up_read(&mm->mmap_sem); > if (pages <= 0) > return -EFAULT; > > diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c > index 8035cc1..dab8b19 100644 > --- a/virt/kvm/async_pf.c > +++ b/virt/kvm/async_pf.c > @@ -76,16 +76,20 @@ static void async_pf_execute(struct work_struct *work) > struct kvm_vcpu *vcpu = apf->vcpu; > unsigned long addr = apf->addr; > gva_t gva = apf->gva; > + int locked = 1; > > might_sleep(); > > /* > * This work is run asynchromously to the task which owns > * mm and might be done in another context, so we must > - * use FOLL_REMOTE. > + * access remotely. > */ > - __get_user_pages_unlocked(NULL, mm, addr, 1, NULL, > - FOLL_WRITE | FOLL_REMOTE); > + down_read(&mm->mmap_sem); > + get_user_pages_remote(NULL, mm, addr, 1, FOLL_WRITE, NULL, NULL, > + &locked); > + if (locked) > + up_read(&mm->mmap_sem); > > kvm_async_page_present_sync(vcpu, apf); > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 2907b7b..c45d951 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1415,13 +1415,12 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault, > npages = get_user_page_nowait(addr, write_fault, page); > up_read(¤t->mm->mmap_sem); > } else { > - unsigned int flags = FOLL_TOUCH | FOLL_HWPOISON; > + unsigned int flags = FOLL_HWPOISON; > > if (write_fault) > flags |= FOLL_WRITE; > > - npages = __get_user_pages_unlocked(current, current->mm, addr, 1, > - page, flags); > + npages = get_user_pages_unlocked(addr, 1, page, flags); > } > if (npages != 1) > return npages; > -- > 2.10.1 -- Michal Hocko SUSE Labs ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 0/2] mm: unexport __get_user_pages_unlocked() 2016-10-27 9:51 [PATCH 0/2] mm: unexport __get_user_pages_unlocked() Lorenzo Stoakes 2016-10-27 9:51 ` [PATCH 1/2] mm: add locked parameter to get_user_pages_remote() Lorenzo Stoakes 2016-10-27 9:51 ` [PATCH 2/2] mm: unexport __get_user_pages_unlocked() Lorenzo Stoakes @ 2016-10-27 9:54 ` Lorenzo Stoakes 2 siblings, 0 replies; 7+ messages in thread From: Lorenzo Stoakes @ 2016-10-27 9:54 UTC (permalink / raw) To: linux-mm Cc: Michal Hocko, Linus Torvalds, Jan Kara, Hugh Dickins, Dave Hansen, Rik van Riel, Mel Gorman, Andrew Morton, Paolo Bonzini, Radim Krčmář, kvm, linux-kernel, linux-security-module, linux-rdma, dri-devel, linux-fsdevel On Thu, Oct 27, 2016 at 10:51:39AM +0100, Lorenzo Stoakes wrote: > This patch series continues the cleanup of get_user_pages*() functions taking > advantage of the fact we can now pass gup_flags as we please. Note that this patch series has an unfortunate trivial dependency on my recent 'fix up get_user_pages* comments' patch which means this series applies against -mmots but not mainline at this point in time. ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-10-27 15:20 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2016-10-27 9:51 [PATCH 0/2] mm: unexport __get_user_pages_unlocked() Lorenzo Stoakes 2016-10-27 9:51 ` [PATCH 1/2] mm: add locked parameter to get_user_pages_remote() Lorenzo Stoakes 2016-10-27 10:55 ` Michal Hocko 2016-10-27 10:59 ` Michal Hocko 2016-10-27 9:51 ` [PATCH 2/2] mm: unexport __get_user_pages_unlocked() Lorenzo Stoakes 2016-10-27 10:57 ` Michal Hocko 2016-10-27 9:54 ` [PATCH 0/2] " Lorenzo Stoakes
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