return copy_to_user(arg, &pd, sizeof(pd)) ? -EFAULT : 0;
 }
 
+static long ptp_pin_setfunc(struct ptp_clock *ptp, unsigned int cmd, void __user *arg)
+{
+       struct ptp_clock_info *ops = ptp->info;
+       struct ptp_pin_desc pd;
+       unsigned int pin_index;
+
+       if (copy_from_user(&pd, arg, sizeof(pd)))
+               return -EFAULT;
+
+       if (cmd == PTP_PIN_SETFUNC2 && !mem_is_zero(pd.rsv, sizeof(pd.rsv)))
+               return -EINVAL;
+
+       if (pd.index >= ops->n_pins)
+               return -EINVAL;
+
+       pin_index = array_index_nospec(pd.index, ops->n_pins);
+       scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux)
+               return ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan);
+}
+
 long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
               unsigned long arg)
 {
        struct ptp_clock *ptp =
                container_of(pccontext->clk, struct ptp_clock, clock);
-       struct ptp_clock_info *ops = ptp->info;
        struct timestamp_event_queue *tsevq;
-       unsigned int i, pin_index;
-       struct ptp_pin_desc pd;
        void __user *argptr;
+       unsigned int i;
        int err = 0;
 
        if (in_compat_syscall() && cmd != PTP_ENABLE_PPS && cmd != PTP_ENABLE_PPS2)
 
        case PTP_PIN_SETFUNC:
        case PTP_PIN_SETFUNC2:
-               if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) {
-                       err = -EACCES;
-                       break;
-               }
-               if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
-                       err = -EFAULT;
-                       break;
-               }
-               if ((pd.rsv[0] || pd.rsv[1] || pd.rsv[2]
-                               || pd.rsv[3] || pd.rsv[4])
-                       && cmd == PTP_PIN_SETFUNC2) {
-                       err = -EINVAL;
-                       break;
-               } else if (cmd == PTP_PIN_SETFUNC) {
-                       pd.rsv[0] = 0;
-                       pd.rsv[1] = 0;
-                       pd.rsv[2] = 0;
-                       pd.rsv[3] = 0;
-                       pd.rsv[4] = 0;
-               }
-               pin_index = pd.index;
-               if (pin_index >= ops->n_pins) {
-                       err = -EINVAL;
-                       break;
-               }
-               pin_index = array_index_nospec(pin_index, ops->n_pins);
-               if (mutex_lock_interruptible(&ptp->pincfg_mux))
-                       return -ERESTARTSYS;
-               err = ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan);
-               mutex_unlock(&ptp->pincfg_mux);
-               break;
+               if ((pccontext->fp->f_mode & FMODE_WRITE) == 0)
+                       return -EACCES;
+               return ptp_pin_setfunc(ptp, cmd, argptr);
 
        case PTP_MASK_CLEAR_ALL:
                bitmap_clear(tsevq->mask, 0, PTP_MAX_CHANNELS);