On Thu, 1 Mar 2012 20:22:59 +0100 Daniel Vetter daniel.vetter@ffwll.ch wrote:
drm/i915 wants to read/write more than one page in its fastpath and hence needs to prefault more than PAGE_SIZE bytes.
Add new functions in filemap.h to make that possible.
Also kill a copy&pasted spurious space in both functions while at it.
...
+/* Multipage variants of the above prefault helpers, useful if more than
- PAGE_SIZE of date 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. */
Like this please:
/* * Multipage variants of the above prefault helpers, useful if more than * PAGE_SIZE of date 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. */
and s/date/data/
+static inline int fault_in_multipages_writeable(char __user *uaddr, int size) +{
- int ret;
- const char __user *end = uaddr + size - 1;
- if (unlikely(size == 0))
return 0;- /*
* Writing zeroes into userspace here is OK, because we know that if* the zero gets there, we'll be overwriting it.*/
Yeah, like that.
- while (uaddr <= end) {
ret = __put_user(0, uaddr);if (ret != 0)return ret;uaddr += PAGE_SIZE;- }
- /* 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 ret;
+}
+static inline int fault_in_multipages_readable(const char __user *uaddr,
int size)+{
- volatile char c;
- int ret;
- const char __user *end = uaddr + size - 1;
- if (unlikely(size == 0))
return 0;- while (uaddr <= end) {
ret = __get_user(c, uaddr);if (ret != 0)return ret;uaddr += PAGE_SIZE;- }
- /* 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 ret;
+}
Please merge it via the DRI tree.