On Wed, 8 Aug 2007 21:18:25 -0700 (PDT) Linus Torvalds <[EMAIL PROTECTED]> wrote:
> > > On Wed, 8 Aug 2007, Chris Snook wrote: > > > > Some architectures currently do not declare the contents of an atomic_t to > > be > > volatile. This causes confusion since atomic_read() might not actually read > > anything if an optimizing compiler re-uses a value stored in a register, > > which > > can break code that loops until something external changes the value of an > > atomic_t. > > I'd be *much* happier with "atomic_read()" doing the "volatile" instead. > > The fact is, volatile on data structures is a bug. It's a wart in the C > language. It shouldn't be used. Why? It's a wart! Is it due to unclear C standard on volatile related point? Why the *volatile-accesses-in-code* is acceptable, does C standard make it clear? -- Jerry > > Volatile accesses in *code* can be ok, and if we have "atomic_read()" > expand to a "*(volatile int *)&(x)->value", then I'd be ok with that. > > But marking data structures volatile just makes the compiler screw up > totally, and makes code for initialization sequences etc much worse. > > Linus - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
