bcachefs: Don't disable preemption unnecessarily

Small improvements to some percpu utility code.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/util.c

@@ -893,13 +893,9 @@ void eytzinger0_find_test(void)
  */
 u64 *bch2_acc_percpu_u64s(u64 __percpu *p, unsigned nr)
 {
-	u64 *ret;
+	u64 *ret = this_cpu_ptr(p);
 	int cpu;
 
-	preempt_disable();
-	ret = this_cpu_ptr(p);
-	preempt_enable();
-
 	for_each_possible_cpu(cpu) {
 		u64 *i = per_cpu_ptr(p, cpu);
 

fs/bcachefs/util.h

@@ -715,10 +715,7 @@ static inline void percpu_u64_set(u64 __percpu *dst, u64 src)
 
 	for_each_possible_cpu(cpu)
 		*per_cpu_ptr(dst, cpu) = 0;
-
-	preempt_disable();
-	*this_cpu_ptr(dst) = src;
-	preempt_enable();
+	this_cpu_write(*dst, src);
 }
 
 static inline void acc_u64s(u64 *acc, const u64 *src, unsigned nr)