minios: blkfront_aio_poll may reenter
if the callback calls blkfront_sync for instance.
In such a case, we would see responses and hence release grants several
times. We huts need to be more synchronous and stop when we detect that
we have re-entered.
This fixes HVM restore with stubdomains.
Signed-off-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxxx>
diff -r 91c4e704169d extras/mini-os/blkfront.c
--- a/extras/mini-os/blkfront.c Wed Mar 26 11:28:47 2008 +0000
+++ b/extras/mini-os/blkfront.c Wed Mar 26 12:07:07 2008 +0000
@@ -319,6 +319,7 @@ int blkfront_aio_poll(struct blkfront_de
 {
 RING_IDX rp, cons;
 struct blkif_response *rsp;
+ int more;
 
 moretodo:
 #ifdef HAVE_LIBC
@@ -334,6 +335,7 @@ moretodo:
 while ((cons != rp))
 {
 rsp = RING_GET_RESPONSE(&dev->ring, cons);
+ nr_consumed++;
 
 if (rsp->status != BLKIF_RSP_OKAY)
 printk("block error %d for op %d\n", rsp->status, rsp->operation);
@@ -343,29 +345,30 @@ moretodo:
 case BLKIF_OP_WRITE:
 {
 struct blkfront_aiocb *aiocbp = (void*) (uintptr_t) rsp->id;
+ int status = rsp->status;
 int j;
 
 for (j = 0; j < aiocbp->n; j++)
 gnttab_end_access(aiocbp->gref[j]);
 
+ dev->ring.rsp_cons = ++cons;
 /* Nota: callback frees aiocbp itself */
- aiocbp->aio_cb(aiocbp, rsp->status ? -EIO : 0);
+ aiocbp->aio_cb(aiocbp, status ? -EIO : 0);
+ if (dev->ring.rsp_cons != cons)
+ /* We reentered, we must not continue here */
+ goto out;
 break;
 }
+ default:
+ printk("unrecognized block operation %d response\n", 
rsp->operation);
 case BLKIF_OP_WRITE_BARRIER:
 case BLKIF_OP_FLUSH_DISKCACHE:
- break;
- default:
- printk("unrecognized block operation %d response\n", 
rsp->operation);
+ dev->ring.rsp_cons = ++cons;
 break;
 }
+ }
 
- nr_consumed++;
- ++cons;
- }
- dev->ring.rsp_cons = cons;
-
- int more;
+out:
 RING_FINAL_CHECK_FOR_RESPONSES(&dev->ring, more);
 if (more) goto moretodo;
 
diff -r 91c4e704169d extras/mini-os/minios.mk
--- a/extras/mini-os/minios.mk Wed Mar 26 11:28:47 2008 +0000
+++ b/extras/mini-os/minios.mk Wed Mar 26 12:07:07 2008 +0000
@@ -16,10 +16,10 @@ DEF_LDFLAGS =
 
 ifeq ($(debug),y)
 DEF_CFLAGS += -g
-#DEF_CFLAGS += MM_DEBUG
-#DEF_CFLAGS += FS_DEBUG
-#DEF_CFLAGS += LIBC_DEBUG
-#DEF_CFLAGS += GNT_DEBUG
+#DEF_CFLAGS += -DMM_DEBUG
+#DEF_CFLAGS += -DFS_DEBUG
+#DEF_CFLAGS += -DLIBC_DEBUG
+DEF_CFLAGS += -DGNT_DEBUG
 else
 DEF_CFLAGS += -O3
 endif
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