ptp: Return -EFAULT on copy_to_user() errors

copy_to_user() returns the number of bytes remaining, but we want a
negative error code in ptp_ioctl.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: John Stultz <john.stultz@linaro.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index a8d03aeb4051..93fa22de5977 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -46,7 +46,8 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
                 caps.n_ext_ts = ptp->info->n_ext_ts;
                 caps.n_per_out = ptp->info->n_per_out;
                 caps.pps = ptp->info->pps;
-                err = copy_to_user((void __user *)arg, &caps, sizeof(caps));
+                if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
+                        err = -EFAULT;
                 break;
 
         case PTP_EXTTS_REQUEST: