Re: [PATCH v3 5/6] inode: port __I_LRU_ISOLATING to var event

[Jan Kara <jack@suse.cz>]

On Fri 23-08-24 14:47:39, Christian Brauner wrote:
> Port the __I_LRU_ISOLATING mechanism to use the new var event mechanism.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/inode.c | 27 +++++++++++++++++++--------
>  1 file changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/inode.c b/fs/inode.c
> index 37f20c7c2f72..8fb8e4f9acc3 100644
> --- 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);
>  }
>  
>  /**
> 
> -- 
> 2.43.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR