On Fri 23-08-24 14:47:37, Christian Brauner wrote:
> Port the __I_SYNC mechanism to use the new var event mechanism.
>
> Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/fs-writeback.c | 45 +++++++++++++++++++++++++++++----------------
> 1 file changed, 29 insertions(+), 16 deletions(-)
>
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 1a5006329f6f..d8bec3c1bb1f 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -1386,12 +1386,13 @@ static void requeue_io(struct inode *inode, struct bdi_writeback *wb)
>
> static void inode_sync_complete(struct inode *inode)
> {
> + assert_spin_locked(&inode->i_lock);
> +
> inode->i_state &= ~I_SYNC;
> /* If inode is clean an unused, put it into LRU now... */
> inode_add_lru(inode);
> - /* Waiters must see I_SYNC cleared before being woken up */
> - smp_mb();
> - wake_up_bit(&inode->i_state, __I_SYNC);
> + /* Called with inode->i_lock which ensures memory ordering. */
> + inode_wake_up_bit(inode, __I_SYNC);
> }
>
> static bool inode_dirtied_after(struct inode *inode, unsigned long t)
> @@ -1512,17 +1513,25 @@ static int write_inode(struct inode *inode, struct writeback_control *wbc)
> */
> void inode_wait_for_writeback(struct inode *inode)
> {
> - DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC);
> - wait_queue_head_t *wqh;
> + struct wait_bit_queue_entry wqe;
> + struct wait_queue_head *wq_head;
> +
> + assert_spin_locked(&inode->i_lock);
> +
> + if (!(inode->i_state & I_SYNC))
> + return;
>
> - lockdep_assert_held(&inode->i_lock);
> - wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
> - while (inode->i_state & I_SYNC) {
> + wq_head = inode_bit_waitqueue(&wqe, inode, __I_SYNC);
> + for (;;) {
> + prepare_to_wait_event(wq_head, &wqe.wq_entry, TASK_UNINTERRUPTIBLE);
> + /* Checking I_SYNC with inode->i_lock guarantees memory ordering. */
> + if (!(inode->i_state & I_SYNC))
> + break;
> spin_unlock(&inode->i_lock);
> - __wait_on_bit(wqh, &wq, bit_wait,
> - TASK_UNINTERRUPTIBLE);
> + schedule();
> spin_lock(&inode->i_lock);
> }
> + finish_wait(wq_head, &wqe.wq_entry);
> }
>
> /*
> @@ -1533,16 +1542,20 @@ void inode_wait_for_writeback(struct inode *inode)
> static void inode_sleep_on_writeback(struct inode *inode)
> __releases(inode->i_lock)
> {
> - DEFINE_WAIT(wait);
> - wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
> - int sleep;
> + struct wait_bit_queue_entry wqe;
> + struct wait_queue_head *wq_head;
> + bool sleep;
> +
> + assert_spin_locked(&inode->i_lock);
>
> - prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
> - sleep = inode->i_state & I_SYNC;
> + wq_head = inode_bit_waitqueue(&wqe, inode, __I_SYNC);
> + prepare_to_wait_event(wq_head, &wqe.wq_entry, TASK_UNINTERRUPTIBLE);
> + /* Checking I_SYNC with inode->i_lock guarantees memory ordering. */
> + sleep = !!(inode->i_state & I_SYNC);
> spin_unlock(&inode->i_lock);
> if (sleep)
> schedule();
> - finish_wait(wqh, &wait);
> + finish_wait(wq_head, &wqe.wq_entry);
> }
>
> /*
>
> --
> 2.43.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
