Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

This update brings dataplane to virtio-scsi (NOT
yet 100% thread-safe, though, which makes it really, really
experimental.  It also brings asynchronous cancellation to
the SCSI subsystem and implements it in virtio-scsi.  This
is a pretty important feature.  Almost all the work here
was done by Fam Zheng.

I also included the virtio refcount fixes from Gonglei,
because they had a small conflict with virtio-scsi dataplane.

This pull request is using the new subkey 4E6B09D7.

# gpg: Signature made Tue 30 Sep 2014 12:31:02 BST using RSA key ID 4E6B09D7
# gpg: Good signature from "Paolo Bonzini <pbonzini@redhat.com>"
# gpg:                 aka "Paolo Bonzini <bonzini@gnu.org>"

* remotes/bonzini/tags/for-upstream: (39 commits)
  block/iscsi: handle failure on malloc of the allocationmap
  util: introduce bitmap_try_new
  virtio-scsi: Handle TMF request cancellation asynchronously
  scsi: Introduce scsi_req_cancel_async
  scsi: Introduce scsi_req_cancel_complete
  scsi: Drop SCSIReqOps.cancel_io
  scsi: Unify request unref in scsi_req_cancel
  scsi-generic: Handle canceled request in scsi_command_complete
  scsi: Drop scsi_req_abort
  virtio-scsi: Process ".iothread" property
  virtio-scsi: Call bdrv_io_plug/bdrv_io_unplug in cmd request handling
  virtio-scsi: Batched prepare for cmd reqs
  virtio-scsi: Two stages processing of cmd request
  virtio-scsi: Add migration state notifier for dataplane code
  virtio-scsi: Hook up with dataplane
  virtio-scsi-dataplane: Code to run virtio-scsi on iothread
  virtio-scsi: Add VirtIOSCSIVring in VirtIOSCSIReq
  virtio-scsi: Add 'iothread' property to virtio-scsi
  virtio: add a wrapper for virtio-backend initialization
  virtio-9p: fix virtio-9p child refcount in transports
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 9 insertions, 28 deletions

diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 20587b41c1..01bca084e6 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -93,6 +93,10 @@ static void scsi_command_complete(void *opaque, int ret)
     SCSIGenericReq *r = (SCSIGenericReq *)opaque;
 
     r->req.aiocb = NULL;
+    if (r->req.io_canceled) {
+        scsi_req_cancel_complete(&r->req);
+        goto done;
+    }
     if (r->io_header.driver_status & SG_ERR_DRIVER_SENSE) {
         r->req.sense_len = r->io_header.sb_len_wr;
     }
@@ -133,26 +137,8 @@ static void scsi_command_complete(void *opaque, int ret)
             r, r->req.tag, status);
 
     scsi_req_complete(&r->req, status);
-    if (!r->req.io_canceled) {
-        scsi_req_unref(&r->req);
-    }
-}
-
-/* Cancel a pending data transfer.  */
-static void scsi_cancel_io(SCSIRequest *req)
-{
-    SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
-
-    DPRINTF("Cancel tag=0x%x\n", req->tag);
-    if (r->req.aiocb) {
-        bdrv_aio_cancel(r->req.aiocb);
-
-        /* This reference was left in by scsi_*_data.  We take ownership of
-         * it independent of whether bdrv_aio_cancel completes the request
-         * or not.  */
-        scsi_req_unref(&r->req);
-    }
-    r->req.aiocb = NULL;
+done:
+    scsi_req_unref(&r->req);
 }
 
 static int execute_command(BlockDriverState *bdrv,
@@ -186,8 +172,7 @@ static void scsi_read_complete(void * opaque, int ret)
     int len;
 
     r->req.aiocb = NULL;
-    if (ret) {
-        DPRINTF("IO error ret %d\n", ret);
+    if (ret || r->req.io_canceled) {
         scsi_command_complete(r, ret);
         return;
     }
@@ -211,9 +196,7 @@ static void scsi_read_complete(void * opaque, int ret)
         bdrv_set_guest_block_size(s->conf.bs, s->blocksize);
 
         scsi_req_data(&r->req, len);
-        if (!r->req.io_canceled) {
-            scsi_req_unref(&r->req);
-        }
+        scsi_req_unref(&r->req);
     }
 }
 
@@ -246,8 +229,7 @@ static void scsi_write_complete(void * opaque, int ret)
 
     DPRINTF("scsi_write_complete() ret = %d\n", ret);
     r->req.aiocb = NULL;
-    if (ret) {
-        DPRINTF("IO error\n");
+    if (ret || r->req.io_canceled) {
         scsi_command_complete(r, ret);
         return;
     }
@@ -465,7 +447,6 @@ const SCSIReqOps scsi_generic_req_ops = {
     .send_command = scsi_send_command,
     .read_data    = scsi_read_data,
     .write_data   = scsi_write_data,
-    .cancel_io    = scsi_cancel_io,
     .get_buf      = scsi_get_buf,
     .load_request = scsi_generic_load_request,
     .save_request = scsi_generic_save_request,