dentry: Use preempt_[dis|en]able_nested()

Replace the open coded CONFIG_PREEMPT_RT conditional
preempt_disable/enable() with the new helper.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20220825164131.402717-3-bigeasy@linutronix.de

diff --git a/fs/dcache.c b/fs/dcache.c
index bb0c4d0..2ee8636 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2597,15 +2597,7 @@ EXPORT_SYMBOL(d_rehash);
 
 static inline unsigned start_dir_add(struct inode *dir)
 {
-       /*
-        * The caller holds a spinlock (dentry::d_lock). On !PREEMPT_RT
-        * kernels spin_lock() implicitly disables preemption, but not on
-        * PREEMPT_RT.  So for RT it has to be done explicitly to protect
-        * the sequence count write side critical section against a reader
-        * or another writer preempting, which would result in a live lock.
-        */
-       if (IS_ENABLED(CONFIG_PREEMPT_RT))
-               preempt_disable();
+       preempt_disable_nested();
        for (;;) {
                unsigned n = dir->i_dir_seq;
                if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
@@ -2618,8 +2610,7 @@ static inline void end_dir_add(struct inode *dir, unsigned int n,
                               wait_queue_head_t *d_wait)
 {
        smp_store_release(&dir->i_dir_seq, n + 2);
-       if (IS_ENABLED(CONFIG_PREEMPT_RT))
-               preempt_enable();
+       preempt_enable_nested();
        wake_up_all(d_wait);
 }