linux-imx

    /*

     * F_SETSIG can change ->signum lockless in parallel, make

     * sure we read it once and use the same value throughout.

     */

    int signum = READ_ONCE(fown->signum);

​

    if (!sigio_perm(p, fown, signum))

        return;

​

    switch (signum) {

        default:

            /* Queue a rt signal with the appropriate fd as its

               value.  We use SI_SIGIO as the source, not 

               SI_KERNEL, since kernel signals always get 

               delivered even if we can't queue.  Failure to

               queue in this case _should_ be reported; we fall

               back to SIGIO in that case. --sct */

            clear_siginfo(&si);

            si.si_signo = signum;

            si.si_errno = 0;