Linux: fix zfs_uio_dio_check_for_zero_page

The intent here is to replace the zero page pointer in the array of
pointers to pages in the struct.

Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Pavel Snajdr <[email protected]>
Closes #16812 
Closes #16689
Closes #16642

Author: snajpa

module/os/linux/zfs/zfs_uio.c

@@ -546,8 +546,9 @@ zfs_uio_dio_check_for_zero_page(zfs_uio_t *uio)
 			unlock_page(p);
 			put_page(p);
 
-			p = __page_cache_alloc(gfp_zero_page);
-			zfs_mark_page(p);
+			uio->uio_dio.pages[i] =
+			    __page_cache_alloc(gfp_zero_page);
+			zfs_mark_page(uio->uio_dio.pages[i]);
 		} else {
 			unlock_page(p);
 		}