Kernel default security configuration - how it affects LSM policy?

One of the choices of security options proposes to select default security

CONFIG_DEFAULT_SECURITY

User can select traditional Unix DAC or one of LSMs.

Suppose CONFIG_DEFAULT_SECURITY_DAC=y selected.

I wonder how it affects LSM policy decisions?

Lets take file permissions

file fs/namei.c, kernel 4.8

__inode_permission ---> do_inode_permission --> generic_permission :

/*

* Do the basic permission checks.

*/

ret = acl_permission_check(inode, mask);

if (capable_wrt_inode_uidgid(inode, CAP_DAC_READ_SEARCH))

return 0;

do_inode_permission(inode, mask);

if (retval)

return retval;

...

retval = devcgroup_inode_permission(inode, mask);

if (retval)

return retval;

return security_inode_permission(inode, mask);

from reading the code we see that first file ACL is consulted, then unix UID/GID then

capabilties and finally security_inode_permissions, i.e LSM

So the questioned config option seems obsolete ?

Wheher LSM always consulted last ?

Am I write ? Perhaps I miss another code path?

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