diff options
Diffstat (limited to 'include/linux/pagemap.h')
-rw-r--r-- | include/linux/pagemap.h | 93 |
1 files changed, 22 insertions, 71 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 66a1260..cb2e1d0 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -518,109 +518,60 @@ void page_endio(struct page *page, bool is_write, int err); extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter); /* - * Fault one or two userspace pages into pagetables. - * Return -EINVAL if more than two pages would be needed. - * Return non-zero on a fault. + * Fault everything in given userspace address range in. */ static inline int fault_in_pages_writeable(char __user *uaddr, int size) { - int span, ret; - - if (unlikely(size == 0)) - return 0; - - span = offset_in_page(uaddr) + size; - if (span > 2 * PAGE_SIZE) - return -EINVAL; - /* - * Writing zeroes into userspace here is OK, because we know that if - * the zero gets there, we'll be overwriting it. - */ - ret = __put_user(0, uaddr); - if (ret == 0 && span > PAGE_SIZE) - ret = __put_user(0, uaddr + size - 1); - return ret; -} - -static inline int fault_in_pages_readable(const char __user *uaddr, int size) -{ - volatile char c; - int ret; - - if (unlikely(size == 0)) - return 0; - - ret = __get_user(c, uaddr); - if (ret == 0) { - const char __user *end = uaddr + size - 1; - - if (((unsigned long)uaddr & PAGE_MASK) != - ((unsigned long)end & PAGE_MASK)) { - ret = __get_user(c, end); - (void)c; - } - } - return ret; -} - -/* - * Multipage variants of the above prefault helpers, useful if more than - * PAGE_SIZE of data needs to be prefaulted. These are separate from the above - * functions (which only handle up to PAGE_SIZE) to avoid clobbering the - * filemap.c hotpaths. - */ -static inline int fault_in_multipages_writeable(char __user *uaddr, int size) -{ - int ret = 0; char __user *end = uaddr + size - 1; if (unlikely(size == 0)) - return ret; + return 0; + if (unlikely(uaddr > end)) + return -EFAULT; /* * Writing zeroes into userspace here is OK, because we know that if * the zero gets there, we'll be overwriting it. */ - while (uaddr <= end) { - ret = __put_user(0, uaddr); - if (ret != 0) - return ret; + do { + if (unlikely(__put_user(0, uaddr) != 0)) + return -EFAULT; uaddr += PAGE_SIZE; - } + } while (uaddr <= end); /* Check whether the range spilled into the next page. */ if (((unsigned long)uaddr & PAGE_MASK) == ((unsigned long)end & PAGE_MASK)) - ret = __put_user(0, end); + return __put_user(0, end); - return ret; + return 0; } -static inline int fault_in_multipages_readable(const char __user *uaddr, - int size) +static inline int fault_in_pages_readable(const char __user *uaddr, int size) { volatile char c; - int ret = 0; const char __user *end = uaddr + size - 1; if (unlikely(size == 0)) - return ret; + return 0; + + if (unlikely(uaddr > end)) + return -EFAULT; - while (uaddr <= end) { - ret = __get_user(c, uaddr); - if (ret != 0) - return ret; + do { + if (unlikely(__get_user(c, uaddr) != 0)) + return -EFAULT; uaddr += PAGE_SIZE; - } + } while (uaddr <= end); /* Check whether the range spilled into the next page. */ if (((unsigned long)uaddr & PAGE_MASK) == ((unsigned long)end & PAGE_MASK)) { - ret = __get_user(c, end); - (void)c; + return __get_user(c, end); } - return ret; + (void)c; + return 0; } int add_to_page_cache_locked(struct page *page, struct address_space *mapping, |