Re: [PATCH 02/10] mm: remove write/force parameters from __get_user_pages_unlocked()
On Thu 13-10-16 01:20:12, Lorenzo Stoakes wrote: > This patch removes the write and force parameters from > __get_user_pages_unlocked() to make the use of FOLL_FORCE explicit in callers > as > use of this flag can result in surprising behaviour (and hence bugs) within > the > mm subsystem. > > Signed-off-by: Lorenzo StoakesThe patch looks good. You can add: Reviewed-by: Jan Kara Honza -- Jan Kara SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 02/10] mm: remove write/force parameters from __get_user_pages_unlocked()
On 13/10/2016 02:20, Lorenzo Stoakes wrote: > This patch removes the write and force parameters from > __get_user_pages_unlocked() to make the use of FOLL_FORCE explicit in callers > as > use of this flag can result in surprising behaviour (and hence bugs) within > the > mm subsystem. > > Signed-off-by: Lorenzo Stoakes> --- > include/linux/mm.h | 3 +-- > mm/gup.c | 17 + > mm/nommu.c | 12 +--- > mm/process_vm_access.c | 7 +-- > virt/kvm/async_pf.c| 3 ++- > virt/kvm/kvm_main.c| 11 --- > 6 files changed, 34 insertions(+), 19 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index e9caec6..2db98b6 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1285,8 +1285,7 @@ long get_user_pages_locked(unsigned long start, > unsigned long nr_pages, > int write, int force, 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, > -int write, int force, struct page **pages, > -unsigned int gup_flags); > +struct page **pages, unsigned int gup_flags); > long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, > int write, int force, struct page **pages); > int get_user_pages_fast(unsigned long start, int nr_pages, int write, > diff --git a/mm/gup.c b/mm/gup.c > index ba83942..3d620dd 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -865,17 +865,11 @@ EXPORT_SYMBOL(get_user_pages_locked); > */ > __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, > struct mm_struct *mm, > unsigned long start, unsigned > long nr_pages, > -int write, int force, struct > page **pages, > -unsigned int gup_flags) > +struct page **pages, unsigned > int gup_flags) > { > long ret; > int locked = 1; > > - if (write) > - gup_flags |= FOLL_WRITE; > - if (force) > - gup_flags |= FOLL_FORCE; > - > down_read(>mmap_sem); > ret = __get_user_pages_locked(tsk, mm, start, nr_pages, pages, NULL, > , false, gup_flags); > @@ -905,8 +899,15 @@ EXPORT_SYMBOL(__get_user_pages_unlocked); > long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, >int write, int force, struct page **pages) > { > + unsigned int flags = FOLL_TOUCH; > + > + if (write) > + flags |= FOLL_WRITE; > + if (force) > + flags |= FOLL_FORCE; > + > return __get_user_pages_unlocked(current, current->mm, start, nr_pages, > - write, force, pages, FOLL_TOUCH); > + pages, flags); > } > EXPORT_SYMBOL(get_user_pages_unlocked); > > diff --git a/mm/nommu.c b/mm/nommu.c > index 95daf81..925dcc1 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -185,8 +185,7 @@ 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, > -int write, int force, struct page **pages, > -unsigned int gup_flags) > +struct page **pages, unsigned int gup_flags) > { > long ret; > down_read(>mmap_sem); > @@ -200,8 +199,15 @@ EXPORT_SYMBOL(__get_user_pages_unlocked); > long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, >int write, int force, struct page **pages) > { > + unsigned int flags = 0; > + > + if (write) > + flags |= FOLL_WRITE; > + if (force) > + flags |= FOLL_FORCE; > + > return __get_user_pages_unlocked(current, current->mm, start, nr_pages, > - write, force, pages, 0); > + pages, flags); > } > EXPORT_SYMBOL(get_user_pages_unlocked); > > diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c > index 07514d4..be8dc8d 100644 > --- a/mm/process_vm_access.c > +++ b/mm/process_vm_access.c > @@ -88,12 +88,16 @@ 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; > > /* Work out address and page range required */ > if (len == 0) > return 0; > nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1; > > + if (vm_write) > +
[PATCH 02/10] mm: remove write/force parameters from __get_user_pages_unlocked()
This patch removes the write and force parameters from __get_user_pages_unlocked() to make the use of FOLL_FORCE explicit in callers as use of this flag can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes--- include/linux/mm.h | 3 +-- mm/gup.c | 17 + mm/nommu.c | 12 +--- mm/process_vm_access.c | 7 +-- virt/kvm/async_pf.c| 3 ++- virt/kvm/kvm_main.c| 11 --- 6 files changed, 34 insertions(+), 19 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index e9caec6..2db98b6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1285,8 +1285,7 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, int write, int force, 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, - int write, int force, struct page **pages, - unsigned int gup_flags); + struct page **pages, unsigned int gup_flags); long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages); int get_user_pages_fast(unsigned long start, int nr_pages, int write, diff --git a/mm/gup.c b/mm/gup.c index ba83942..3d620dd 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -865,17 +865,11 @@ EXPORT_SYMBOL(get_user_pages_locked); */ __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, - unsigned int gup_flags) + struct page **pages, unsigned int gup_flags) { long ret; int locked = 1; - if (write) - gup_flags |= FOLL_WRITE; - if (force) - gup_flags |= FOLL_FORCE; - down_read(>mmap_sem); ret = __get_user_pages_locked(tsk, mm, start, nr_pages, pages, NULL, , false, gup_flags); @@ -905,8 +899,15 @@ EXPORT_SYMBOL(__get_user_pages_unlocked); long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages) { + unsigned int flags = FOLL_TOUCH; + + if (write) + flags |= FOLL_WRITE; + if (force) + flags |= FOLL_FORCE; + return __get_user_pages_unlocked(current, current->mm, start, nr_pages, -write, force, pages, FOLL_TOUCH); +pages, flags); } EXPORT_SYMBOL(get_user_pages_unlocked); diff --git a/mm/nommu.c b/mm/nommu.c index 95daf81..925dcc1 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -185,8 +185,7 @@ 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, - int write, int force, struct page **pages, - unsigned int gup_flags) + struct page **pages, unsigned int gup_flags) { long ret; down_read(>mmap_sem); @@ -200,8 +199,15 @@ EXPORT_SYMBOL(__get_user_pages_unlocked); long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages) { + unsigned int flags = 0; + + if (write) + flags |= FOLL_WRITE; + if (force) + flags |= FOLL_FORCE; + return __get_user_pages_unlocked(current, current->mm, start, nr_pages, -write, force, pages, 0); +pages, flags); } EXPORT_SYMBOL(get_user_pages_unlocked); diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index 07514d4..be8dc8d 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -88,12 +88,16 @@ 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; /* Work out address and page range required */ if (len == 0) return 0; nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1; + if (vm_write) + flags |= FOLL_WRITE; + while (!rc && nr_pages && iov_iter_count(iter)) { int pages = min(nr_pages, max_pages_per_loop); size_t bytes; @@ -104,8