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    SubjectRe: [PATCH, RFC] fasync() BKL pushdown
    Jonathan Corbet wrote:
    > On Fri, 20 Jun 2008 19:55:03 +0200
    > Andi Kleen <> wrote:
    >> Jonathan Corbet 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.
    >> Not necessarily true, they might require BKL still for fd live time
    >> issues.
    > Could you help me out a bit here? I'm even slower than usual when it
    > comes to VFS stuff. As far as I can tell, the given file cannot go
    > away during the call to fasync(), as sys_fcntl() holds a reference on
    > it. Are you saying that something else can happen during that time?

    Some devices do state change even when the reference count is > 0.
    Would need to double check it's all ok with the fasync list.

    Anyways I did this auditing for the cases where I used unlocked_ioctl
    [but I think I wanted to redo it because i wasn't 100% sure anymore]
    and I haven't done it at all for the cases that weren't converted.


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      Last update: 2008-06-20 21:15    [W:0.031 / U:50.244 seconds]
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