diff options
| -rw-r--r-- | drivers/infiniband/hw/ipath/ipath_user_pages.c | 6 | ||||
| -rw-r--r-- | drivers/infiniband/hw/qib/qib_user_pages.c | 6 | ||||
| -rw-r--r-- | include/linux/mm.h | 4 | ||||
| -rw-r--r-- | mm/internal.h | 5 | ||||
| -rw-r--r-- | mm/memory.c | 50 |
5 files changed, 60 insertions, 11 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_user_pages.c b/drivers/infiniband/hw/ipath/ipath_user_pages.c index bab9f74c066..cfed5399f07 100644 --- a/drivers/infiniband/hw/ipath/ipath_user_pages.c +++ b/drivers/infiniband/hw/ipath/ipath_user_pages.c @@ -53,8 +53,8 @@ static void __ipath_release_user_pages(struct page **p, size_t num_pages, } /* call with current->mm->mmap_sem held */ -static int __get_user_pages(unsigned long start_page, size_t num_pages, - struct page **p, struct vm_area_struct **vma) +static int __ipath_get_user_pages(unsigned long start_page, size_t num_pages, + struct page **p, struct vm_area_struct **vma) { unsigned long lock_limit; size_t got; @@ -165,7 +165,7 @@ int ipath_get_user_pages(unsigned long start_page, size_t num_pages, down_write(¤t->mm->mmap_sem); - ret = __get_user_pages(start_page, num_pages, p, NULL); + ret = __ipath_get_user_pages(start_page, num_pages, p, NULL); up_write(¤t->mm->mmap_sem); diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c index d7a26c1d4f3..7689e49c13c 100644 --- a/drivers/infiniband/hw/qib/qib_user_pages.c +++ b/drivers/infiniband/hw/qib/qib_user_pages.c @@ -51,8 +51,8 @@ static void __qib_release_user_pages(struct page **p, size_t num_pages, /* * Call with current->mm->mmap_sem held. */ -static int __get_user_pages(unsigned long start_page, size_t num_pages, - struct page **p, struct vm_area_struct **vma) +static int __qib_get_user_pages(unsigned long start_page, size_t num_pages, + struct page **p, struct vm_area_struct **vma) { unsigned long lock_limit; size_t got; @@ -136,7 +136,7 @@ int qib_get_user_pages(unsigned long start_page, size_t num_pages, down_write(¤t->mm->mmap_sem); - ret = __get_user_pages(start_page, num_pages, p, NULL); + ret = __qib_get_user_pages(start_page, num_pages, p, NULL); up_write(¤t->mm->mmap_sem); diff --git a/include/linux/mm.h b/include/linux/mm.h index 679300c050f..46150c66318 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -965,6 +965,10 @@ static inline int handle_mm_fault(struct mm_struct *mm, extern int make_pages_present(unsigned long addr, unsigned long end); extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write); +int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, int len, unsigned int foll_flags, + struct page **pages, struct vm_area_struct **vmas, + int *nonblocking); int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int nr_pages, int write, int force, struct page **pages, struct vm_area_struct **vmas); diff --git a/mm/internal.h b/mm/internal.h index 69488205723..3438dd43a06 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -245,11 +245,6 @@ static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn, } #endif /* CONFIG_SPARSEMEM */ -int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, int len, unsigned int foll_flags, - struct page **pages, struct vm_area_struct **vmas, - int *nonblocking); - #define ZONE_RECLAIM_NOSCAN -2 #define ZONE_RECLAIM_FULL -1 #define ZONE_RECLAIM_SOME 0 diff --git a/mm/memory.c b/mm/memory.c index 5823698c2b7..806a37ec71b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1410,6 +1410,55 @@ no_page_table: return page; } +/** + * __get_user_pages() - pin user pages in memory + * @tsk: task_struct of target task + * @mm: mm_struct of target mm + * @start: starting user address + * @nr_pages: number of pages from start to pin + * @gup_flags: flags modifying pin behaviour + * @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. + * @nonblocking: whether waiting for disk IO or mmap_sem contention + * + * 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 + * were pinned, returns -errno. Each page returned must be released + * with a put_page() call when it is finished with. vmas will only + * remain valid while mmap_sem is held. + * + * Must be called with mmap_sem held for read or write. + * + * __get_user_pages walks a process's page tables and takes a reference to + * each struct page that each user address corresponds to at a given + * instant. That is, it takes the page that would be accessed if a user + * thread accesses the given user virtual address at that instant. + * + * This does not guarantee that the page exists in the user mappings when + * __get_user_pages returns, and there may even be a completely different + * page there in some cases (eg. if mmapped pagecache has been invalidated + * and subsequently re faulted). However it does guarantee that the page + * won't be freed completely. And mostly callers simply care that the page + * contains data that was valid *at some point in time*. Typically, an IO + * or similar operation cannot guarantee anything stronger anyway because + * locks can't be held over the syscall boundary. + * + * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If + * the page is written to, set_page_dirty (or set_page_dirty_lock, as + * appropriate) must be called after the page is finished with, and + * before put_page is called. + * + * If @nonblocking != NULL, __get_user_pages will not wait for disk IO + * or mmap_sem contention, and if waiting is needed to pin all pages, + * *@nonblocking will be set to 0. + * + * In most cases, get_user_pages or get_user_pages_fast should be used + * instead of __get_user_pages. __get_user_pages should be used only if + * you need some special @gup_flags. + */ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int nr_pages, unsigned int gup_flags, struct page **pages, struct vm_area_struct **vmas, @@ -1578,6 +1627,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, } while (nr_pages); return i; } +EXPORT_SYMBOL(__get_user_pages); /** * get_user_pages() - pin user pages in memory |