s390: Replace weird use of PTR_RET.

Saves repeating "(void __force *)__uptr" but it's less clear.  Using
the output of PTR_RET() to determine the error rather than just
testing IS_ERR() is odd.

For example, I *assume* __gptr_to_uptr() never returns NULL?  Because
the __ret would be 0 for the old code.  The new version is clearer, IMHO:
it would try to get_user() on that address.

If you hate this variant, I can just s/PTR_RET/PTR_ERR_OR_ZERO/ instead.

Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 302e0e52b009..99d789e8a018 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -42,9 +42,11 @@ static inline void __user *__gptr_to_uptr(struct kvm_vcpu *vcpu,
 ({                                                              \
         __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
         int __mask = sizeof(__typeof__(*(gptr))) - 1;           \
-        int __ret = PTR_RET((void __force *)__uptr);            \
+        int __ret;                                              \
                                                                 \
-        if (!__ret) {                                           \
+        if (IS_ERR((void __force *)__uptr)) {                   \
+                __ret = PTR_ERR((void __force *)__uptr);        \
+        } else {                                                \
                 BUG_ON((unsigned long)__uptr & __mask);         \
                 __ret = get_user(x, __uptr);                    \
         }                                                       \
@@ -55,9 +57,11 @@ static inline void __user *__gptr_to_uptr(struct kvm_vcpu *vcpu,
 ({                                                              \
         __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
         int __mask = sizeof(__typeof__(*(gptr))) - 1;           \
-        int __ret = PTR_RET((void __force *)__uptr);            \
+        int __ret;                                              \
                                                                 \
-        if (!__ret) {                                           \
+        if (IS_ERR((void __force *)__uptr)) {                   \
+                __ret = PTR_ERR((void __force *)__uptr);        \
+        } else {                                                \
                 BUG_ON((unsigned long)__uptr & __mask);         \
                 __ret = put_user(x, __uptr);                    \
         }                                                       \