lkml.org 
[lkml]   [2007]   [Oct]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 1/2] irq_flags_t: intro and core annotations
    Andrew Morton wrote:
    > Linus Torvalds <torvalds@linux-foundation.org> wrote:

    >> > On Mon, 22 Oct 2007, Matthew Wilcox wrote:
    >>> > > We certainly don't want to encourage people to blindly make those
    >>> > > conversions ... and I've seen the results of encouraging kernel janitors
    >>> > > to do things a certain way.

    >> > There's another issue: the "irqsave/irqrestore" versions are much safer
    >> > than the plain "irq" versions, in case the caller already has interrupts
    >> > disabled.

    > It's almost always a bug to do spin_lock_irq() when local interrupts are
    > disabled.


    Let me add to the chorus of voices: I continually see two cases where
    real bugs crop up:

    1) hacker uses spin_lock_irq() in incorrect context (where it is not
    safe to do a blind enable/disable)

    2) hacker uses spin_lock_irq() correctly, but the surrounding code
    changes, thus invalidating prior assumptions.

    I would even go so far as to support the drastic measure of deleting
    spin_lock_irq().

    spin_lock_irqsave() generates fewer bugs, is more future-proof, and by
    virtue of 'flags' permits architectures a bit more flexibility.

    Jeff



    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-10-22 22:51    [W:0.063 / U:29.832 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site