kill iov_iter_copy_from_user()

all callers can use copy_page_from_iter() and it actually simplifies
them.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ceph/file.c

@@ -737,13 +737,12 @@ static ssize_t ceph_sync_write(struct kiocb *iocb, const struct iovec *iov,
 		left = len;
 		for (n = 0; n < num_pages; n++) {
 			size_t plen = min_t(size_t, left, PAGE_SIZE);
-			ret = iov_iter_copy_from_user(pages[n], &i, 0, plen);
+			ret = copy_page_from_iter(pages[n], 0, plen, &i);
 			if (ret != plen) {
 				ret = -EFAULT;
 				break;
 			}
 			left -= ret;
-			iov_iter_advance(&i, ret);
 		}
 
 		if (ret < 0) {

fs/cifs/file.c

@@ -2444,11 +2444,10 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
 
 		save_len = cur_len;
 		for (i = 0; i < nr_pages; i++) {
-			bytes = min_t(const size_t, cur_len, PAGE_SIZE);
-			copied = iov_iter_copy_from_user(wdata->pages[i], &it,
-							 0, bytes);
+			bytes = min_t(size_t, cur_len, PAGE_SIZE);
+			copied = copy_page_from_iter(wdata->pages[i], 0, bytes,
+						     &it);
 			cur_len -= copied;
-			iov_iter_advance(&it, copied);
 			/*
 			 * If we didn't copy as much as we expected, then that
 			 * may mean we trod into an unmapped area. Stop copying

include/linux/uio.h

@@ -62,8 +62,6 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
 
 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,
-		struct iov_iter *i, unsigned long offset, size_t bytes);
 void iov_iter_advance(struct iov_iter *i, size_t bytes);
 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
 size_t iov_iter_single_seg_count(const struct iov_iter *i);

mm/iov_iter.c

@@ -129,33 +129,6 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
 }
 EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
 
-/*
- * This has the same sideeffects and return value as
- * iov_iter_copy_from_user_atomic().
- * The difference is that it attempts to resolve faults.
- * Page must not be locked.
- */
-size_t iov_iter_copy_from_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_from_user(kaddr + offset, buf, bytes);
-		copied = bytes - left;
-	} else {
-		copied = __iovec_copy_from_user_inatomic(kaddr + offset,
-						i->iov, i->iov_offset, bytes);
-	}
-	kunmap(page);
-	return copied;
-}
-EXPORT_SYMBOL(iov_iter_copy_from_user);
-
 void iov_iter_advance(struct iov_iter *i, size_t bytes)
 {
 	BUG_ON(i->count < bytes);

mm/process_vm_access.c

@@ -46,11 +46,7 @@ static int process_vm_rw_pages(struct page **pages,
 			copy = len;
 
 		if (vm_write) {
-			if (copy > iov_iter_count(iter))
-				copy = iov_iter_count(iter);
-			copied = iov_iter_copy_from_user(page, iter,
-					offset, copy);
-			iov_iter_advance(iter, copied);
+			copied = copy_page_from_iter(page, offset, copy, iter);
 			set_page_dirty_lock(page);
 		} else {
 			copied = copy_page_to_iter(page, offset, copy, iter);