inode: port __I_LRU_ISOLATING to var event

Port the __I_LRU_ISOLATING mechanism to use the new var event mechanism.

Link: https://lore.kernel.org/r/20240823-work-i_state-v3-5-5cd5fd207a57@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/inode.c b/fs/inode.c
index 1aa785421f1349423777979a825df761b99b278e..aacd05749c1f854a31ba36f3fb5bee1ec8886cc6 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -511,24 +511,35 @@ static void inode_unpin_lru_isolating(struct inode *inode)
        spin_lock(&inode->i_lock);
        WARN_ON(!(inode->i_state & I_LRU_ISOLATING));
        inode->i_state &= ~I_LRU_ISOLATING;
-       smp_mb();
-       wake_up_bit(&inode->i_state, __I_LRU_ISOLATING);
+       /* Called with inode->i_lock which ensures memory ordering. */
+       inode_wake_up_bit(inode, __I_LRU_ISOLATING);
        spin_unlock(&inode->i_lock);
 }
 
 static void inode_wait_for_lru_isolating(struct inode *inode)
 {
+       struct wait_bit_queue_entry wqe;
+       struct wait_queue_head *wq_head;
+
        lockdep_assert_held(&inode->i_lock);
-       if (inode->i_state & I_LRU_ISOLATING) {
-               DEFINE_WAIT_BIT(wq, &inode->i_state, __I_LRU_ISOLATING);
-               wait_queue_head_t *wqh;
+       if (!(inode->i_state & I_LRU_ISOLATING))
+               return;
 
-               wqh = bit_waitqueue(&inode->i_state, __I_LRU_ISOLATING);
+       wq_head = inode_bit_waitqueue(&wqe, inode, __I_LRU_ISOLATING);
+       for (;;) {
+               prepare_to_wait_event(wq_head, &wqe.wq_entry, TASK_UNINTERRUPTIBLE);
+               /*
+                * Checking I_LRU_ISOLATING with inode->i_lock guarantees
+                * memory ordering.
+                */
+               if (!(inode->i_state & I_LRU_ISOLATING))
+                       break;
                spin_unlock(&inode->i_lock);
-               __wait_on_bit(wqh, &wq, bit_wait, TASK_UNINTERRUPTIBLE);
+               schedule();
                spin_lock(&inode->i_lock);
-               WARN_ON(inode->i_state & I_LRU_ISOLATING);
        }
+       finish_wait(wq_head, &wqe.wq_entry);
+       WARN_ON(inode->i_state & I_LRU_ISOLATING);
 }
 
 /**