cvs commit: src/sys/alpha/alpha busdma_machdep.csrc/sys/i386/i386 busdma_machdep.c src/sys/ia64/ia64 busdma_machdep.c src/sys/powerpc/powerpc busdma_machdep.c

[Nate Lawson]

On Fri, 27 Jun 2003, Scott Long wrote:
>   Do the first and mostly mechanical step of adding mutex support to the
>   bus_dma async callback scheme.  Note that sparc64 does not seem to do
>   async callbacks.  Note that ia64 callbacks might not be MPSAFE at the
>   moment.  Note that powerpc doesn't seem to do async callbacks due to
>   the implementation being incomplete.
>
>   Reviewed by:    mostly silence on arch@
>
>   Revision  Changes    Path
>   1.39      +5 -0      src/sys/alpha/alpha/busdma_machdep.c
>   1.47      +5 -0      src/sys/i386/i386/busdma_machdep.c
>   1.25      +5 -0      src/sys/ia64/ia64/busdma_machdep.c
>   1.16      +1 -0      src/sys/powerpc/powerpc/busdma_machdep.c
>
> @@ -931,8 +932,12 @@
>  	while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
>  		STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
>  		mtx_unlock(&bounce_lock);
> +		if (map->callback_mtx != NULL)
> +			mtx_lock(map->callback_mtx);
>  		bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
>  				map->callback, map->callback_arg, /*flags*/0);
> +		if (map->callback_mtx != NULL)
> +			mtx_unlock(map->callback_mtx);
>  		mtx_lock(&bounce_lock);
>  	}
>  	mtx_unlock(&bounce_lock);

Good to see you working on this area.  Why would callback_mtx be null?  If
it is null, is it safe to call the function without the lock held?

-Nate