qed: Remove recursion in qed_aio_next_io()

Instead of calling itself recursively as the last thing, just convert
qed_aio_next_io() into a loop.

This patch is best reviewed with 'git show -w' because most of it is
just whitespace changes.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

block/qed.c

@@ -1280,45 +1280,46 @@ static void qed_aio_next_io(QEDAIOCB *acb)
     size_t len;
     int ret;
 
-    trace_qed_aio_next_io(s, acb, 0, acb->cur_pos + acb->cur_qiov.size);
+    while (1) {
+        trace_qed_aio_next_io(s, acb, 0, acb->cur_pos + acb->cur_qiov.size);
 
-    if (acb->backing_qiov) {
-        qemu_iovec_destroy(acb->backing_qiov);
-        g_free(acb->backing_qiov);
-        acb->backing_qiov = NULL;
-    }
+        if (acb->backing_qiov) {
+            qemu_iovec_destroy(acb->backing_qiov);
+            g_free(acb->backing_qiov);
+            acb->backing_qiov = NULL;
+        }
 
-    acb->qiov_offset += acb->cur_qiov.size;
-    acb->cur_pos += acb->cur_qiov.size;
-    qemu_iovec_reset(&acb->cur_qiov);
+        acb->qiov_offset += acb->cur_qiov.size;
+        acb->cur_pos += acb->cur_qiov.size;
+        qemu_iovec_reset(&acb->cur_qiov);
 
-    /* Complete request */
-    if (acb->cur_pos >= acb->end_pos) {
-        qed_aio_complete(acb, 0);
-        return;
-    }
+        /* Complete request */
+        if (acb->cur_pos >= acb->end_pos) {
+            qed_aio_complete(acb, 0);
+            return;
+        }
 
-    /* Find next cluster and start I/O */
-    len = acb->end_pos - acb->cur_pos;
-    ret = qed_find_cluster(s, &acb->request, acb->cur_pos, &len, &offset);
-    if (ret < 0) {
-        qed_aio_complete(acb, ret);
-        return;
-    }
+        /* Find next cluster and start I/O */
+        len = acb->end_pos - acb->cur_pos;
+        ret = qed_find_cluster(s, &acb->request, acb->cur_pos, &len, &offset);
+        if (ret < 0) {
+            qed_aio_complete(acb, ret);
+            return;
+        }
 
-    if (acb->flags & QED_AIOCB_WRITE) {
-        ret = qed_aio_write_data(acb, ret, offset, len);
-    } else {
-        ret = qed_aio_read_data(acb, ret, offset, len);
-    }
+        if (acb->flags & QED_AIOCB_WRITE) {
+            ret = qed_aio_write_data(acb, ret, offset, len);
+        } else {
+            ret = qed_aio_read_data(acb, ret, offset, len);
+        }
 
-    if (ret < 0) {
-        if (ret != -EINPROGRESS) {
-            qed_aio_complete(acb, ret);
+        if (ret < 0) {
+            if (ret != -EINPROGRESS) {
+                qed_aio_complete(acb, ret);
+            }
+            return;
         }
-        return;
     }
-    qed_aio_next_io(acb);
 }
 
 static BlockAIOCB *qed_aio_setup(BlockDriverState *bs,