In some cases a request may be canceled before the completion
callback runs. Keep a reference to the request between starting
an AIO operation, and let scsi_*_complete remove it.
Since scsi_handle_rw_error returns whether something else has to
be done for the request by the caller, it makes sense to transfer
ownership of the ref to scsi_handle_rw_error when it returns 1;
scsi_dma_restart_bh will then free the reference after restarting
the operation.
Signed-off-by: Paolo Bonzini<address@hidden>
---
v1->v2: Add "return" after calling scsi_write_complete with
ENOMEDIUM. Bump refcount before testing data direction.
hw/scsi-disk.c | 16 ++++++++++++++++
1 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index e28c39d..702e6ca 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -139,6 +139,7 @@ static void scsi_read_complete(void * opaque, int ret)
if (ret) {
if (scsi_handle_rw_error(r, -ret, SCSI_REQ_STATUS_RETRY_READ)) {
+ /* Leave in ref for scsi_dma_restart_bh. */
return;
}
}
@@ -149,6 +150,7 @@ static void scsi_read_complete(void * opaque, int ret)
r->sector += n;
r->sector_count -= n;
scsi_req_data(&r->req, r->qiov.size);
+ scsi_req_unref(&r->req);
}
static void scsi_flush_complete(void * opaque, int ret)
@@ -163,11 +165,13 @@ static void scsi_flush_complete(void * opaque, int ret)
if (ret< 0) {
if (scsi_handle_rw_error(r, -ret, SCSI_REQ_STATUS_RETRY_FLUSH)) {
+ /* Leave in ref for scsi_dma_restart_bh. */
return;
}
}
scsi_req_complete(&r->req, GOOD);
+ scsi_req_unref(&r->req);
}
/* Read more data from scsi device into buffer. */
@@ -193,6 +197,8 @@ static void scsi_read_data(SCSIRequest *req)
/* No data transfer may already be in progress */
assert(r->req.aiocb == NULL);
+ /* Save a ref for scsi_read_complete, in case r is canceled. */
+ scsi_req_ref(&r->req);
if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
DPRINTF("Data transfer direction invalid\n");
scsi_read_complete(r, -EINVAL);
@@ -201,7 +207,9 @@ static void scsi_read_data(SCSIRequest *req)
if (s->tray_open) {
scsi_read_complete(r, -ENOMEDIUM);
+ return;
}
+
n = scsi_init_iovec(r);
bdrv_acct_start(s->bs,&r->acct, n * BDRV_SECTOR_SIZE, BDRV_ACCT_READ);
r->req.aiocb = bdrv_aio_readv(s->bs, r->sector,&r->qiov, n,
@@ -279,6 +287,7 @@ static void scsi_write_complete(void * opaque, int ret)
DPRINTF("Write complete tag=0x%x more=%d\n", r->req.tag,
r->qiov.size);
scsi_req_data(&r->req, r->qiov.size);
}
+ scsi_req_unref(&r->req);
}
static void scsi_write_data(SCSIRequest *req)
@@ -290,6 +299,8 @@ static void scsi_write_data(SCSIRequest *req)
/* No data transfer may already be in progress */
assert(r->req.aiocb == NULL);
+ /* Save a ref for scsi_write_complete, in case r is canceled. */
+ scsi_req_ref(&r->req);
if (r->req.cmd.mode != SCSI_XFER_TO_DEV) {
DPRINTF("Data transfer direction invalid\n");
scsi_write_complete(r, -EINVAL);
@@ -300,6 +311,7 @@ static void scsi_write_data(SCSIRequest *req)
if (n) {
if (s->tray_open) {
scsi_write_complete(r, -ENOMEDIUM);
+ return;
}
bdrv_acct_start(s->bs,&r->acct, n * BDRV_SECTOR_SIZE,
BDRV_ACCT_WRITE);
r->req.aiocb = bdrv_aio_writev(s->bs, r->sector,&r->qiov, n,
@@ -344,6 +356,8 @@ static void scsi_dma_restart_bh(void *opaque)
scsi_req_complete(&r->req, GOOD);
}
}
+ /* This reference was left in by scsi_handle_rw_error. */
+ scsi_req_unref(&r->req);
}
}
}
@@ -1345,6 +1359,8 @@ static int32_t scsi_send_command(SCSIRequest *req,
uint8_t *buf)
r->iov.iov_len = rc;
break;
case SYNCHRONIZE_CACHE:
+ /* Save a ref for scsi_flush_complete, in case r is canceled. */
+ scsi_req_ref(&r->req);
bdrv_acct_start(s->bs,&r->acct, 0, BDRV_ACCT_FLUSH);
r->req.aiocb = bdrv_aio_flush(s->bs, scsi_flush_complete, r);
if (r->req.aiocb == NULL) {