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/** * inode_dio_wait - wait for outstanding DIO requests to finish * @inode: inode to wait for * * Waits for all pending direct I/O requests to finish so that we can * proceed with a truncate or equivalent operation. * * Must be called under a lock that serializes taking new references * to i_dio_count, usually by inode->i_mutex. */void inode_dio_wait(struct inode *inode){	if (atomic_read(&inode->i_dio_count))		__inode_dio_wait(inode);}EXPORT_SYMBOL(inode_dio_wait);

/* * Direct i/o helper functions */static void __inode_dio_wait(struct inode *inode){	wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);	DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);	do {		prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE);		if (atomic_read(&inode->i_dio_count))			schedule();	} while (atomic_read(&inode->i_dio_count));	finish_wait(wq, &q.wait);}

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