[PATCH 3/9] dentry: Use preempt_[dis|en]able_nested()

Sebastian Andrzej Siewior
2022-08-17T16:27:58Z

From: Thomas Gleixner <tglx@linutronix.de>

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

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
fs/dcache.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index c5dc32a59c769..e633b20623d0f 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2571,15 +2571,7 @@ 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)
@@ -2592,8 +2584,7 @@ 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);
}

--
2.37.2