On Wed, 2007-07-25 at 07:37 +1000, Benjamin Herrenschmidt wrote: > On Tue, 2007-07-24 at 11:13 -0700, Linus Torvalds wrote: > > > > IOW, if you do a spinlock with the bitops, the locking side should be > > able > > to use a "test_and_set_bit()" on its own, but the unlocking side > > should be > > > > smp_mb__before_clear_bit(); > > clear_bit(); > > > > because the ones that don't return a value also don't imply a memory > > barrier. > > Yup. But I much prefer Nick's clear_bit_unlock() :-) > > Ben If you want to use bitops as spinlocks you should rather be using <linux/bit_spinlock.h>. That also does the right thing w.r.t. pre-emption and sparse locking annotations. Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] 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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