ide: Fix ide_dma_cancel

When cancelling a request, bdrv_aio_cancel may decide that it waits for
completion of a request rather than for cancellation. IDE therefore can't
abandon its DMA status before calling bdrv_aio_cancel; otherwise the callback
of a completed request would use invalid data.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hw/ide/core.c

diff --git a/hw/ide/core.c b/hw/ide/core.c
index b0165bc..066fecb 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -2838,10 +2838,6 @@
 void ide_dma_cancel(BMDMAState *bm)
 {
     if (bm->status & BM_STATUS_DMAING) {
-        bm->status &= ~BM_STATUS_DMAING;
-        /* cancel DMA request */
-        bm->unit = -1;
-        bm->dma_cb = NULL;
         if (bm->aiocb) {
 #ifdef DEBUG_AIO
             printf("aio_cancel\n");
@@ -2849,6 +2845,10 @@
             bdrv_aio_cancel(bm->aiocb);
             bm->aiocb = NULL;
         }
+        bm->status &= ~BM_STATUS_DMAING;
+        /* cancel DMA request */
+        bm->unit = -1;
+        bm->dma_cb = NULL;
     }
 }