#include <linux/highmem.h>
#include <linux/pagemap.h>
+static size_t __iovec_copy_to_user(char *vaddr, const struct iovec *iov,
+ size_t base, size_t bytes, int atomic)
+{
+ size_t copied = 0, left = 0;
+
+ while (bytes) {
+ char __user *buf = iov->iov_base + base;
+ int copy = min(bytes, iov->iov_len - base);
+
+ base = 0;
+ if (atomic)
+ left = __copy_to_user_inatomic(buf, vaddr, copy);
+ else
+ left = copy_to_user(buf, vaddr, copy);
+ copied += copy;
+ bytes -= copy;
+ vaddr += copy;
+ iov++;
+
+ if (unlikely(left))
+ break;
+ }
+ return copied - left;
+}
+
+/*
+ * Copy as much as we can into the page and return the number of bytes which
+ * were sucessfully copied. If a fault is encountered then return the number of
+ * bytes which were copied.
+ */
+size_t iov_iter_copy_to_user_atomic(struct page *page,
+ struct iov_iter *i, unsigned long offset, size_t bytes)
+{
+ char *kaddr;
+ size_t copied;
+
+ BUG_ON(!in_atomic());
+ kaddr = kmap_atomic(page);
+ if (likely(i->nr_segs == 1)) {
+ int left;
+ char __user *buf = i->iov->iov_base + i->iov_offset;
+ left = __copy_to_user_inatomic(buf, kaddr + offset, bytes);
+ copied = bytes - left;
+ } else {
+ copied = __iovec_copy_to_user(kaddr + offset, i->iov,
+ i->iov_offset, bytes, 1);
+ }
+ kunmap_atomic(kaddr);
+
+ return copied;
+}
+EXPORT_SYMBOL(iov_iter_copy_to_user_atomic);
+
+/*
+ * This has the same sideeffects and return value as
+ * iov_iter_copy_to_user_atomic().
+ * The difference is that it attempts to resolve faults.
+ * Page must not be locked.
+ */
+size_t iov_iter_copy_to_user(struct page *page,
+ struct iov_iter *i, unsigned long offset, size_t bytes)
+{
+ char *kaddr;
+ size_t copied;
+
+ kaddr = kmap(page);
+ if (likely(i->nr_segs == 1)) {
+ int left;
+ char __user *buf = i->iov->iov_base + i->iov_offset;
+ left = copy_to_user(buf, kaddr + offset, bytes);
+ copied = bytes - left;
+ } else {
+ copied = __iovec_copy_to_user(kaddr + offset, i->iov,
+ i->iov_offset, bytes, 0);
+ }
+ kunmap(page);
+ return copied;
+}
+EXPORT_SYMBOL(iov_iter_copy_to_user);
+
static size_t __iovec_copy_from_user(char *vaddr, const struct iovec *iov,
size_t base, size_t bytes, int atomic)
{
size_t count;
};
+size_t iov_iter_copy_to_user_atomic(struct page *page,
+ struct iov_iter *i, unsigned long offset, size_t bytes);
+size_t iov_iter_copy_to_user(struct page *page,
+ struct iov_iter *i, unsigned long offset, size_t bytes);
size_t iov_iter_copy_from_user_atomic(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes);
size_t iov_iter_copy_from_user(struct page *page,