From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35592) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZwnEO-0004Cp-QI for qemu-devel@nongnu.org; Thu, 12 Nov 2015 03:27:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZwnEN-0000bP-Sn for qemu-devel@nongnu.org; Thu, 12 Nov 2015 03:27:44 -0500 Date: Thu, 12 Nov 2015 16:27:36 +0800 From: Fam Zheng Message-ID: <20151112082736.GP4082@ad.usersys.redhat.com> References: <1446799373-6144-1-git-send-email-pl@kamp.de> <1446799373-6144-5-git-send-email-pl@kamp.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1446799373-6144-5-git-send-email-pl@kamp.de> Subject: Re: [Qemu-devel] [PATCH V3 4/6] ide: orphan all buffered requests on DMA cancel List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: kwolf@redhat.com, qemu-block@nongnu.org, stefanha@gmail.com, jcody@redhat.com, qemu-devel@nongnu.org, jsnow@redhat.com On Fri, 11/06 09:42, Peter Lieven wrote: > If the guests canceles a DMA request we can prematurely > invoke all callbacks of buffered requests and flag all them > as orphaned. Ideally this avoids the need for draining all > requests. For CDROM devices this works in 100% of all cases. > > Signed-off-by: Peter Lieven > --- > hw/ide/pci.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/hw/ide/pci.c b/hw/ide/pci.c > index d31ff88..a9e164e 100644 > --- a/hw/ide/pci.c > +++ b/hw/ide/pci.c > @@ -240,6 +240,22 @@ void bmdma_cmd_writeb(BMDMAState *bm, uint32_t val) > /* Ignore writes to SSBM if it keeps the old value */ > if ((val & BM_CMD_START) != (bm->cmd & BM_CMD_START)) { > if (!(val & BM_CMD_START)) { > + /* First invoke the callbacks of all buffered requests > + * and flag those requests as orphaned. Ideally there > + * are no unbuffered (Scatter Gather DMA Requests or > + * write requests) pending and we can avoid to drain. */ > + IDEBufferedRequest *req; > + IDEState *s = idebus_active_if(bm->bus); > + QLIST_FOREACH(req, &s->buffered_requests, list) { > + if (!req->orphaned) { > +#ifdef DEBUG_IDE > + printf("%s: invoking cb %p of buffered request %p with" > + " -ECANCELED\n", __func__, req->original_cb, req); > +#endif > + req->original_cb(req->original_opaque, -ECANCELED); > + } > + req->orphaned = true; > + } Why not use bdrv_aio_cancel or bdrv_aio_cancel_async with the aio returned by bdrv_aio_cancel? Fam > /* > * We can't cancel Scatter Gather DMA in the middle of the > * operation or a partial (not full) DMA transfer would reach > @@ -253,6 +269,9 @@ void bmdma_cmd_writeb(BMDMAState *bm, uint32_t val) > * aio operation with preadv/pwritev. > */ > if (bm->bus->dma->aiocb) { > +#ifdef DEBUG_IDE > + printf("%s: draining all remaining requests", __func__); > +#endif > blk_drain_all(); > assert(bm->bus->dma->aiocb == NULL); > } > -- > 1.9.1 > >