Index: /trunk/src/VBox/Additions/linux/sharedfolders/regops.c
===================================================================
--- /trunk/src/VBox/Additions/linux/sharedfolders/regops.c	(revision 88570)
+++ /trunk/src/VBox/Additions/linux/sharedfolders/regops.c	(revision 88571)
@@ -1468,4 +1468,5 @@
 
 
+#if RTLNX_VER_MAX(5,10,0)
 /**
  * Read function used when accessing files that are memory mapped.
@@ -1476,5 +1477,5 @@
 static ssize_t vbsf_reg_read_mapped(struct file *file, char /*__user*/ *buf, size_t size, loff_t *off)
 {
-#if RTLNX_VER_MIN(3,16,0)
+# if RTLNX_VER_MIN(3,16,0)
     struct iovec    iov = { .iov_base = buf, .iov_len = size };
     struct iov_iter iter;
@@ -1491,5 +1492,5 @@
     return cbRet;
 
-#elif RTLNX_VER_MIN(2,6,19)
+# elif RTLNX_VER_MIN(2,6,19)
     struct iovec    iov = { .iov_base = buf, .iov_len = size };
     struct kiocb    kiocb;
@@ -1506,7 +1507,7 @@
     return cbRet;
 
-#else /* 2.6.18 or earlier: */
+# else /* 2.6.18 or earlier: */
     return generic_file_read(file, buf, size, off);
-#endif
+# endif
 }
 
@@ -1626,5 +1627,4 @@
 }
 
-
 /**
  * Read from a regular file.
@@ -1692,5 +1692,5 @@
     }
 
-#if 0 /* Turns out this is slightly slower than locking the pages even for 4KB reads (4.19/amd64). */
+# if 0 /* Turns out this is slightly slower than locking the pages even for 4KB reads (4.19/amd64). */
     /*
      * For medium sized requests try use a bounce buffer.
@@ -1721,8 +1721,9 @@
         }
     }
-#endif
+# endif
 
     return vbsf_reg_read_locking(file, buf, size, off, pSuperInfo, sf_r);
 }
+#endif /* < 5.10.0 */
 
 
@@ -1814,4 +1815,5 @@
 
 
+#if RTLNX_VER_MAX(5,10,0)
 /**
  * Fallback case of vbsf_reg_write() that locks the user buffers and let the host
@@ -1941,5 +1943,4 @@
 }
 
-
 /**
  * Write to a regular file.
@@ -1987,11 +1988,11 @@
         && mapping->nrpages > 0
         && mapping_writably_mapped(mapping)) {
-#if RTLNX_VER_MIN(2,6,32)
+# if RTLNX_VER_MIN(2,6,32)
         int err = filemap_fdatawait_range(mapping, pos, pos + size - 1);
         if (err)
             return err;
-#else
+# else
         /** @todo ...   */
-#endif
+# endif
     }
 
@@ -2035,5 +2036,5 @@
     }
 
-#if 0 /* Turns out this is slightly slower than locking the pages even for 4KB reads (4.19/amd64). */
+# if 0 /* Turns out this is slightly slower than locking the pages even for 4KB reads (4.19/amd64). */
     /*
      * For medium sized requests try use a bounce buffer.
@@ -2074,8 +2075,9 @@
         }
     }
-#endif
+# endif
 
     return vbsf_reg_write_locking(file, buf, size, off, pos, inode, sf_i, pSuperInfo, sf_r);
 }
+#endif /* < 5.10.0 */
 
 #if RTLNX_VER_MIN(2,6,19)
@@ -3506,6 +3508,8 @@
 struct file_operations vbsf_reg_fops = {
     .open            = vbsf_reg_open,
+#if RTLNX_VER_MAX(5,10,0)
     .read            = vbsf_reg_read,
     .write           = vbsf_reg_write,
+#endif
 #if RTLNX_VER_MIN(3,16,0)
     .read_iter       = vbsf_reg_read_iter,