Re: question on read_barrier_depends

From: Oliver Neukum
Date: Thu Apr 17 2014 - 11:16:33 EST


On Wed, 2014-04-16 at 11:26 -0400, Alan Stern wrote:

> In addition, the following code in kfifo_get() does this:
>
> *(typeof(__tmp->type))__val = \
> (__is_kfifo_ptr(__tmp) ? \
> ((typeof(__tmp->type))__kfifo->data) : \
> (__tmp->buf) \
> )[__kfifo->out & __tmp->kfifo.mask]; \
> smp_wmb(); \
> __kfifo->out++; \
>
> It looks like the smp_wmb() should really be smp_mb(), because it
> separates the _read_ for val from the _write_ of kfifo->out.

But where is kfifo->out read at all?

Regards
Oliver



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