Re: [PATCH, RFC] fasync() BKL pushdown

From: Arjan van de Ven
Date: Fri Jun 20 2008 - 16:58:55 EST


On Fri, 20 Jun 2008 11:29:14 -0600
Jonathan Corbet <corbet@xxxxxxx> wrote:
>
> The majority of fasync() functions just call fasync_helper() with a
> pointer to an fasync_struct reachable from the file structure. Given
> that (1) the struct file will not go away while fasync() is running,
> and (2) the VFS-level fasync() stuff is protected with the Big Fasync
> Lock, I contend that these simple implementations have no need for
> the BKL. Once those are filtered out, there's really only a
> half-dozen places which need to be fixed.


> Jonathan Corbet (7):
> mpt: fasync BKL pushdown
> i2o: fasync BKL pushdown
> tun: fasync BKL pushdown
> tty_io: fasync BKL pushdown
> Bluetooth VHCI: fasync BKL pushdown
> ecryptfs: fasync BKL pushdown
> Call fasync() functions without the BKL
>
> And the actual patch is appended. If nobody objects, I'll pull these
> into the bkl-removal tree shortly.
>

looks good to me

only question is if this one is really needed:
+ lock_kernel();
tty = (struct tty_struct *)filp->private_data;
if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode,
"tty_fasync"))
- return 0;
+ goto out;

retval = fasync_helper(fd, filp, on, &tty->fasync);
if (retval <= 0)

(given that it just calls the helper.. mostly and that Alan has been
busy removing the BKL from the tty layer)


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