ptp: Split out PTP_CLOCK_GETCAPS ioctl code

ptp_ioctl() is an inpenetrable letter soup with a gazillion of case (scope)
specific variables defined at the top of the function and pointless breaks
and gotos.

Start cleaning it up by splitting out the PTP_CLOCK_GETCAPS ioctl code into
a helper function. Use a argument pointer with a single sparse compliant
type cast instead of proliferating the type cast all over the place.

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250625115132.733409073@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 4bf421765d03332234aac405fc594842760037f1..a8d85d9dc0946fc305364e3588950ec5a6ebaaf1 100644 (file)
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -157,6 +157,26 @@ int ptp_release(struct posix_clock_context *pccontext)
        return 0;
 }
 
+static long ptp_clock_getcaps(struct ptp_clock *ptp, void __user *arg)
+{
+       struct ptp_clock_caps caps = {
+               .max_adj                = ptp->info->max_adj,
+               .n_alarm                = ptp->info->n_alarm,
+               .n_ext_ts               = ptp->info->n_ext_ts,
+               .n_per_out              = ptp->info->n_per_out,
+               .pps                    = ptp->info->pps,
+               .n_pins                 = ptp->info->n_pins,
+               .cross_timestamping     = ptp->info->getcrosststamp != NULL,
+               .adjust_phase           = ptp->info->adjphase != NULL &&
+                                         ptp->info->getmaxphase != NULL,
+       };
+
+       if (caps.adjust_phase)
+               caps.max_phase_adj = ptp->info->getmaxphase(ptp->info);
+
+       return copy_to_user(arg, &caps, sizeof(caps)) ? -EFAULT : 0;
+}
+
 long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
               unsigned long arg)
 {
@@ -171,37 +191,22 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
        struct timestamp_event_queue *tsevq;
        struct ptp_system_timestamp sts;
        struct ptp_clock_request req;
-       struct ptp_clock_caps caps;
        struct ptp_clock_time *pct;
        struct ptp_pin_desc pd;
        struct timespec64 ts;
        int enable, err = 0;
+       void __user *argptr;
 
        if (in_compat_syscall() && cmd != PTP_ENABLE_PPS && cmd != PTP_ENABLE_PPS2)
                arg = (unsigned long)compat_ptr(arg);
+       argptr = (void __force __user *)arg;
 
        tsevq = pccontext->private_clkdata;
 
        switch (cmd) {
-
        case PTP_CLOCK_GETCAPS:
        case PTP_CLOCK_GETCAPS2:
-               memset(&caps, 0, sizeof(caps));
-
-               caps.max_adj = ptp->info->max_adj;
-               caps.n_alarm = ptp->info->n_alarm;
-               caps.n_ext_ts = ptp->info->n_ext_ts;
-               caps.n_per_out = ptp->info->n_per_out;
-               caps.pps = ptp->info->pps;
-               caps.n_pins = ptp->info->n_pins;
-               caps.cross_timestamping = ptp->info->getcrosststamp != NULL;
-               caps.adjust_phase = ptp->info->adjphase != NULL &&
-                                   ptp->info->getmaxphase != NULL;
-               if (caps.adjust_phase)
-                       caps.max_phase_adj = ptp->info->getmaxphase(ptp->info);
-               if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
-                       err = -EFAULT;
-               break;
+               return ptp_clock_getcaps(ptp, argptr);
 
        case PTP_EXTTS_REQUEST:
        case PTP_EXTTS_REQUEST2: