[Qemu-devel] [PATCH 04/15] qed: make qed_aio_write_alloc() reusable

[Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>]

Copy-on-read requests will share the allocating write code path.  This
requires making qed_aio_write_alloc() reusable outside of a write
request.  This patch ensures that iovec setup is performed in a common
place before qed_aio_write_alloc() is called.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 block/qed.c |   53 +++++++++++++++--------------------------------------
 1 files changed, 15 insertions(+), 38 deletions(-)

diff --git a/block/qed.c b/block/qed.c
index cc193ad..4f535aa 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1133,19 +1133,18 @@ static bool qed_start_allocating_write(QEDAIOCB *acb)
  *
  * This path is taken when writing to previously unallocated clusters.
  */
-static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
+static void qed_aio_write_alloc(QEDAIOCB *acb)
 {
     BDRVQEDState *s = acb_to_s(acb);
-    BlockDriverCompletionFunc *cb;
 
     if (!qed_start_allocating_write(acb)) {
-        return;
+        qemu_iovec_reset(&acb->cur_qiov);
+        return; /* wait until current allocating write completes */
     }
 
     acb->cur_nclusters = qed_bytes_to_clusters(s,
-            qed_offset_into_cluster(s, acb->cur_pos) + len);
+            qed_offset_into_cluster(s, acb->cur_pos) + acb->cur_qiov.size);
     acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters);
-    qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
 
     if (qed_should_set_need_check(s)) {
         s->header.features |= QED_F_NEED_CHECK;
@@ -1156,25 +1155,6 @@ static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
 }
 
 /**
- * Write data cluster in place
- *
- * @acb:        Write request
- * @offset:     Cluster offset in bytes
- * @len:        Length in bytes
- *
- * This path is taken when writing to already allocated clusters.
- */
-static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len)
-{
-    /* Calculate the I/O vector */
-    acb->cur_cluster = offset;
-    qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
-
-    /* Do the actual write */
-    qed_aio_write_main(acb, 0);
-}
-
-/**
  * Write data cluster
  *
  * @opaque:     Write request
@@ -1192,22 +1172,19 @@ static void qed_aio_write_data(void *opaque, int ret,
 
     trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len);
 
-    acb->find_cluster_ret = ret;
-
-    switch (ret) {
-    case QED_CLUSTER_FOUND:
-        qed_aio_write_inplace(acb, offset, len);
-        break;
+    if (ret < 0) {
+        qed_aio_complete(acb, ret);
+        return;
+    }
 
-    case QED_CLUSTER_L2:
-    case QED_CLUSTER_L1:
-    case QED_CLUSTER_ZERO:
-        qed_aio_write_alloc(acb, len);
-        break;
+    acb->find_cluster_ret = ret;
+    qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
 
-    default:
-        qed_aio_complete(acb, ret);
-        break;
+    if (ret == QED_CLUSTER_FOUND) {
+        acb->cur_cluster = offset;
+        qed_aio_write_main(acb, 0);
+    } else {
+        qed_aio_write_alloc(acb);
     }
 }
 
-- 
1.7.5.4