mm/filemap.c: remove unused argument from shrink_readahead_size_eio()

The first argument of shrink_readahead_size_eio() is not used.  Hence
remove it from the function definition and from all the callers.
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1583868093-24342-1-git-send-email-jrdr.linux@gmail.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/filemap.c

@@ -1962,8 +1962,7 @@ EXPORT_SYMBOL(find_get_pages_range_tag);
  *
  * It is going insane. Fix it by quickly scaling down the readahead size.
  */
-static void shrink_readahead_size_eio(struct file *filp,
-					struct file_ra_state *ra)
+static void shrink_readahead_size_eio(struct file_ra_state *ra)
 {
 	ra->ra_pages /= 4;
 }
@@ -2188,7 +2187,7 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb,
 					goto find_page;
 				}
 				unlock_page(page);
-				shrink_readahead_size_eio(filp, ra);
+				shrink_readahead_size_eio(ra);
 				error = -EIO;
 				goto readpage_error;
 			}
@@ -2560,7 +2559,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
 		goto retry_find;
 
 	/* Things didn't work out. Return zero to tell the mm layer so. */
-	shrink_readahead_size_eio(file, ra);
+	shrink_readahead_size_eio(ra);
 	return VM_FAULT_SIGBUS;
 
 out_retry: