mm: deduplicate error handling for map_deny_write_exec

Patch series "Fixes for MDWE prctl"

These are four small fixes for the recent memory-write-deny-execute prctl
patches [1].  Two reported by Alexey about error handling and two tooling
fixes by Peter.


This patch (of 4):

Commit cc8d1b09 ("mmap: clean up mmap_region() unrolling")
deduplicated the error handling, do the same for the return value of
`map_deny_write_exec`.

Link: https://lkml.kernel.org/r/20230308190423.46491-1-joey.gouly@arm.com
Link: https://lkml.kernel.org/r/20230308190423.46491-2-joey.gouly@arm.com
Link: https://lore.kernel.org/linux-arm-kernel/20230119160344.54358-1-joey.gouly@arm.com/ [1]
Fixes: b507808e ("mm: implement memory-deny-write-execute as a prctl")
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Reported-by: Alexey Izbyshev <izbyshev@ispras.ru>
  Link: https://lore.kernel.org/linux-arm-kernel/8408d8901e9d7ee6b78db4c6cba04b78@ispras.ru/Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: nd <nd@arm.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mmap.c

@@ -2621,12 +2621,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 
 	if (map_deny_write_exec(vma, vma->vm_flags)) {
 		error = -EACCES;
-		if (file)
-			goto close_and_free_vma;
-		else if (vma->vm_file)
-			goto unmap_and_free_vma;
-		else
-			goto free_vma;
+		goto close_and_free_vma;
 	}
 
 	/* Allow architectures to sanity-check the vm_flags */