Re: [PATCH] tty_ioctl: locking for tty_wait_until_sent

From: Alan Cox
Date: Mon Mar 10 2008 - 18:20:35 EST


On 10 Mar 2008 23:12:51 +0100
Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:

> Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> writes:
>
> > This function still depends on the big kernel lock in some cases. Push
> > locking into the function ready for removal of the BKL from ioctl call
> > paths.
>
> Didn't you forget the .ioctl -> .unlocked_ioctl change?

We are not yet ready to unlock the device ioctl paths for tty. We still
explicitly take the BKL in the ioctl paths when calling the following
methods

driver:
->wait_until_sent()
->break_ctl()
->tiocmget
->tiocmset
->ioctl
ldisc:
->ioctl

As well as all the open/close/hangup/ldisc change logic

I'm pretty close to removing it from the modem , ioctl and break methods
and its working for me but needs a few drivers tweaking further.

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