x86-64: Fix the failure case in copy_user_handle_tail()
x86-64: Fix the failure case in copy_user_handle_tail()

The increment of "to" in copy_user_handle_tail() will have incremented
before a failure has been noted.  This causes us to skip a byte in the
failure case.

Only do the increment when assured there is no failure.

Signed-off-by: CQ Tang <eaca123aeb461a7006558e7d3ce83b4ed2cb8ee9@intel.com>
Link: e64d778013edee1ead91ee84e7c178477df1b9ce@phlsvslse11.ph.intel.com
Signed-off-by: Mike Marciniszyn <8b6671d72f65e2bb5dd5241f258fc1c5c815d085@intel.com>
Signed-off-by: H. Peter Anvin <8a453bad9912ffe59bc0f0b8abe03df9be19379e@linux.intel.com>
Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas