Messages in this thread | | | Date | Thu, 23 Feb 2006 16:16:31 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] Avoid calling down_read and down_write during startup |
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Benjamin LaHaise <bcrl@kvack.org> wrote: > > On Thu, Feb 23, 2006 at 05:36:56PM -0500, Alan Stern wrote: > > This patch (as660) changes the registration and unregistration routines > > for blocking notifier chains. During system startup, when task switching > > is illegal, the routines will avoid calling down_write(). > > Why is that necessary? The down_write() will immediately succeed as no > other process can possibly be holding the lock when the system is booting, > so the special casing doesn't fix anything.
down_write() unconditionally (and reasonably) does local_irq_enable() in the uncontended case. And enabling local interrupts early in boot can cause crashes. - 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/
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