get rid of separate multipage fault-in primitives

* the only remaining callers of "short" fault-ins are just as happy with generic
variants (both in lib/iov_iter.c); switch them to multipage variants, kill the
"short" ones
* rename the multipage variants to now available plain ones.
* get rid of compat macro defining iov_iter_fault_in_multipage_readable by
expanding it in its only user.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 52 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 01e84436cddf..cb2e1d06d2e9 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -518,59 +518,10 @@ 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)
-{
         char __user *end = uaddr + size - 1;
 
         if (unlikely(size == 0))
@@ -596,8 +547,7 @@ static inline int fault_in_multipages_writeable(char __user *uaddr, int size)
         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;
         const char __user *end = uaddr + size - 1;