Date: Fri, 27 Jun 2003 09:13:35 -0700 (PDT) From: Nate Lawson <nate@root.org> To: Scott Long <scottl@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: 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 Message-ID: <20030627091203.B76929@root.org> In-Reply-To: <20030627083158.E946C37B4A6@hub.freebsd.org> References: <20030627083158.E946C37B4A6@hub.freebsd.org>
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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
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