Re: ANNOUNCE: big change in PCM kernel API

[Alan Cox]

> ALSA has already the same behaviour (also for OSS emulation) and the
> inode lock is dropped on write (to tell you the truth I'd have preferred
> that sys_write transfer the inode->i_sem handling entirely to
> f_op->write, but probably the efficiency impact of the double down/up is
> small)
> 
> I'm not sure to understand the second part (and one sleeping on a write
> locks out the other), can you rephrase that?

If you don't drop the lock then what can occur is what you already avoided
by dropping the lock

Task1
		sys_write(sound_fd, buf, len)
		driver write
		driver does blocking wait for 10 seconds

Task2
		sys_write
			sleep in inode lock for 10 seconds