diff --git a/libc/bionic/pthread_cond.cpp b/libc/bionic/pthread_cond.cpp
index e570602..213bcd7 100644
--- a/libc/bionic/pthread_cond.cpp
+++ b/libc/bionic/pthread_cond.cpp
@@ -96,9 +96,6 @@
 }
 
 int pthread_condattr_destroy(pthread_condattr_t* attr) {
-  if (attr == NULL) {
-    return EINVAL;
-  }
   *attr = 0xdeada11d;
   return 0;
 }
@@ -112,10 +109,6 @@
 // XXX then the signal will be lost.
 
 int pthread_cond_init(pthread_cond_t* cond, const pthread_condattr_t* attr) {
-  if (cond == NULL) {
-    return EINVAL;
-  }
-
   if (attr != NULL) {
     cond->value = (*attr & COND_FLAGS_MASK);
   } else {
@@ -126,10 +119,6 @@
 }
 
 int pthread_cond_destroy(pthread_cond_t* cond) {
-  if (cond == NULL) {
-    return EINVAL;
-  }
-
   cond->value = 0xdeadc04d;
   return 0;
 }
@@ -138,10 +127,6 @@
 // pthread_cond_signal to atomically decrement the counter
 // then wake up 'counter' threads.
 static int __pthread_cond_pulse(pthread_cond_t* cond, int counter) {
-  if (__predict_false(cond == NULL)) {
-    return EINVAL;
-  }
-
   int flags = (cond->value & COND_FLAGS_MASK);
   while (true) {
     int old_value = cond->value;
diff --git a/libc/bionic/pthread_mutex.cpp b/libc/bionic/pthread_mutex.cpp
index 9072605..a2e7b25 100644
--- a/libc/bionic/pthread_mutex.cpp
+++ b/libc/bionic/pthread_mutex.cpp
@@ -207,55 +207,42 @@
 
 int pthread_mutexattr_init(pthread_mutexattr_t *attr)
 {
-    if (attr) {
-        *attr = PTHREAD_MUTEX_DEFAULT;
-        return 0;
-    } else {
-        return EINVAL;
-    }
+    *attr = PTHREAD_MUTEX_DEFAULT;
+    return 0;
 }
 
 int pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
 {
-    if (attr) {
-        *attr = -1;
-        return 0;
-    } else {
-        return EINVAL;
-    }
+    *attr = -1;
+    return 0;
 }
 
-int pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *type)
+int pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *type_p)
 {
-    if (attr) {
-        int  atype = (*attr & MUTEXATTR_TYPE_MASK);
+    int type = (*attr & MUTEXATTR_TYPE_MASK);
 
-         if (atype >= PTHREAD_MUTEX_NORMAL &&
-             atype <= PTHREAD_MUTEX_ERRORCHECK) {
-            *type = atype;
-            return 0;
-        }
+    if (type < PTHREAD_MUTEX_NORMAL || type > PTHREAD_MUTEX_ERRORCHECK) {
+        return EINVAL;
     }
-    return EINVAL;
+
+    *type_p = type;
+    return 0;
 }
 
 int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type)
 {
-    if (attr && type >= PTHREAD_MUTEX_NORMAL &&
-                type <= PTHREAD_MUTEX_ERRORCHECK ) {
-        *attr = (*attr & ~MUTEXATTR_TYPE_MASK) | type;
-        return 0;
+    if (type < PTHREAD_MUTEX_NORMAL || type > PTHREAD_MUTEX_ERRORCHECK ) {
+        return EINVAL;
     }
-    return EINVAL;
+
+    *attr = (*attr & ~MUTEXATTR_TYPE_MASK) | type;
+    return 0;
 }
 
 /* process-shared mutexes are not supported at the moment */
 
 int pthread_mutexattr_setpshared(pthread_mutexattr_t *attr, int  pshared)
 {
-    if (!attr)
-        return EINVAL;
-
     switch (pshared) {
     case PTHREAD_PROCESS_PRIVATE:
         *attr &= ~MUTEXATTR_SHARED_MASK;
@@ -274,11 +261,7 @@
 }
 
 int pthread_mutexattr_getpshared(const pthread_mutexattr_t* attr, int* pshared) {
-    if (!attr || !pshared)
-        return EINVAL;
-
-    *pshared = (*attr & MUTEXATTR_SHARED_MASK) ? PTHREAD_PROCESS_SHARED
-                                               : PTHREAD_PROCESS_PRIVATE;
+    *pshared = (*attr & MUTEXATTR_SHARED_MASK) ? PTHREAD_PROCESS_SHARED : PTHREAD_PROCESS_PRIVATE;
     return 0;
 }
 
diff --git a/libc/bionic/pthread_rwlock.cpp b/libc/bionic/pthread_rwlock.cpp
index 0182ef3..dfb4315 100644
--- a/libc/bionic/pthread_rwlock.cpp
+++ b/libc/bionic/pthread_rwlock.cpp
@@ -60,27 +60,18 @@
 
 int pthread_rwlockattr_init(pthread_rwlockattr_t *attr)
 {
-    if (!attr)
-        return EINVAL;
-
     *attr = PTHREAD_PROCESS_PRIVATE;
     return 0;
 }
 
 int pthread_rwlockattr_destroy(pthread_rwlockattr_t *attr)
 {
-    if (!attr)
-        return EINVAL;
-
     *attr = -1;
     return 0;
 }
 
 int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr, int  pshared)
 {
-    if (!attr)
-        return EINVAL;
-
     switch (pshared) {
     case PTHREAD_PROCESS_PRIVATE:
     case PTHREAD_PROCESS_SHARED:
@@ -92,9 +83,6 @@
 }
 
 int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t* attr, int* pshared) {
-    if (!attr || !pshared)
-        return EINVAL;
-
     *pshared = *attr;
     return 0;
 }
@@ -107,9 +95,6 @@
     pthread_condattr_t    cond_attr0;
     int                   ret;
 
-    if (rwlock == NULL)
-        return EINVAL;
-
     if (attr && *attr == PTHREAD_PROCESS_SHARED) {
         lock_attr = &lock_attr0;
         pthread_mutexattr_init(lock_attr);
@@ -140,9 +125,6 @@
 
 int pthread_rwlock_destroy(pthread_rwlock_t *rwlock)
 {
-    if (rwlock == NULL)
-        return EINVAL;
-
     if (rwlock->numLocks > 0)
         return EBUSY;
 
@@ -197,10 +179,6 @@
 static int __pthread_rwlock_timedrdlock(pthread_rwlock_t* rwlock, const timespec* abs_timeout) {
   int ret = 0;
 
-  if (rwlock == NULL) {
-    return EINVAL;
-  }
-
   pthread_mutex_lock(&rwlock->lock);
   int tid = __get_thread()->tid;
   if (__predict_false(!read_precondition(rwlock, tid))) {
@@ -222,10 +200,6 @@
 static int __pthread_rwlock_timedwrlock(pthread_rwlock_t* rwlock, const timespec* abs_timeout) {
   int ret = 0;
 
-  if (rwlock == NULL) {
-    return EINVAL;
-  }
-
   pthread_mutex_lock(&rwlock->lock);
   int tid = __get_thread()->tid;
   if (__predict_false(!write_precondition(rwlock, tid))) {
@@ -256,9 +230,6 @@
 {
     int ret = 0;
 
-    if (rwlock == NULL)
-        return EINVAL;
-
     pthread_mutex_lock(&rwlock->lock);
     if (__predict_false(!read_precondition(rwlock, __get_thread()->tid)))
         ret = EBUSY;
@@ -281,9 +252,6 @@
 {
     int ret = 0;
 
-    if (rwlock == NULL)
-        return EINVAL;
-
     pthread_mutex_lock(&rwlock->lock);
     int tid = __get_thread()->tid;
     if (__predict_false(!write_precondition(rwlock, tid))) {
@@ -304,9 +272,6 @@
 {
     int  ret = 0;
 
-    if (rwlock == NULL)
-        return EINVAL;
-
     pthread_mutex_lock(&rwlock->lock);
 
     /* The lock must be held */
diff --git a/libc/bionic/pthread_setname_np.cpp b/libc/bionic/pthread_setname_np.cpp
index e0ecace..1ddf810 100644
--- a/libc/bionic/pthread_setname_np.cpp
+++ b/libc/bionic/pthread_setname_np.cpp
@@ -46,10 +46,6 @@
 int pthread_setname_np(pthread_t t, const char* thread_name) {
   ErrnoRestorer errno_restorer;
 
-  if (thread_name == NULL) {
-    return EINVAL;
-  }
-
   size_t thread_name_len = strlen(thread_name);
   if (thread_name_len >= MAX_TASK_COMM_LEN) {
     return ERANGE;