Commit 7cda6208 authored by Peter Lieven's avatar Peter Lieven Committed by John Snow
Browse files

ide: orphan all buffered requests on DMA cancel 



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: default avatarPeter Lieven <pl@kamp.de>
Reviewed-by: default avatarFam Zheng <famz@redhat.com>
Message-id: 1447345846-15624-5-git-send-email-pl@kamp.de
Signed-off-by: default avatarJohn Snow <jsnow@redhat.com>
parent 1d8c11d6

hw/ide/pci.c

+19 −0
Original line number Diff line number Diff line
@@ -233,6 +233,22 @@ 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;

            }

            /*

             * We can't cancel Scatter Gather DMA in the middle of the

             * operation or a partial (not full) DMA transfer would reach
@@ -246,6 +262,9 @@ 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);

            }