[Qemu-devel] [PATCH 9/9] Convert write into 2nd threading model.

[Arun R Bharadwaj <arun@linux.vnet.ibm.com>]

From: Sripathi Kodi <sripathik@in.ibm.com>

Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com>
---
 hw/virtio-9p.c |   92 +++++++++++++++++++++-----------------------------------
 hw/virtio-9p.h |    4 ++
 2 files changed, 39 insertions(+), 57 deletions(-)

diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index 82f0ed2..47bcbd1 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -2244,40 +2244,6 @@ out:
     return;
 }
 
-static void v9fs_write_post_pwritev(V9fsState *s, V9fsWriteState *vs,
-                                   ssize_t err)
-{
-    if (err  < 0) {
-        /* IO error return the error */
-        err = -errno;
-        goto out;
-    }
-    vs->total += vs->len;
-    vs->sg = adjust_sg(vs->sg, vs->len, &vs->cnt);
-    if (vs->total < vs->count && vs->len > 0) {
-        do {
-            if (0) {
-                print_sg(vs->sg, vs->cnt);
-            }
-            vs->len = v9fs_do_pwritev(s, vs->fidp->fs.fd, vs->sg, vs->cnt,
-                      vs->off);
-            if (vs->len > 0) {
-                vs->off += vs->len;
-            }
-        } while (vs->len == -1 && errno == EINTR);
-        if (vs->len == -1) {
-            err  = -errno;
-        }
-        v9fs_write_post_pwritev(s, vs, err);
-        return;
-    }
-    vs->offset += pdu_marshal(vs->pdu, vs->offset, "d", vs->total);
-    err = vs->offset;
-out:
-    complete_pdu(s, vs->pdu, err);
-    qemu_free(vs);
-}
-
 static void v9fs_xattr_write(V9fsState *s, V9fsWriteState *vs)
 {
     int i, to_copy;
@@ -2320,32 +2286,26 @@ out:
     qemu_free(vs);
 }
 
-static void v9fs_write(V9fsState *s, V9fsPDU *pdu)
+static void v9fs_write_do_complete(void *opaque)
 {
-    int32_t fid;
-    V9fsWriteState *vs;
-    ssize_t err;
-
-    vs = qemu_malloc(sizeof(*vs));
+    V9fsWriteState *vs = (V9fsWriteState *)opaque;
 
-    vs->pdu = pdu;
-    vs->offset = 7;
-    vs->sg = vs->iov;
-    vs->total = 0;
-    vs->len = 0;
-
-    pdu_unmarshal(vs->pdu, vs->offset, "dqdv", &fid, &vs->off, &vs->count,
-                  vs->sg, &vs->cnt);
+    complete_pdu(vs->s, vs->pdu, vs->err);
+    qemu_free(vs);
+}
 
-    vs->fidp = lookup_fid(s, fid);
+static void v9fs_write_worker(ThreadletWork *work)
+{
+    V9fsWriteState *vs = container_of(work, V9fsWriteState, work);
+    vs->fidp = lookup_fid(vs->s, vs->fid);
     if (vs->fidp == NULL) {
-        err = -EINVAL;
+        vs->err = -EINVAL;
         goto out;
     }
 
     if (vs->fidp->fid_type == P9_FID_FILE) {
         if (vs->fidp->fs.fd == -1) {
-            err = -EINVAL;
+            vs->err = -EINVAL;
             goto out;
         }
     } else if (vs->fidp->fid_type == P9_FID_XATTR) {
@@ -2355,7 +2315,7 @@ static void v9fs_write(V9fsState *s, V9fsPDU *pdu)
         v9fs_xattr_write(s, vs);
         return;
     } else {
-        err = -EINVAL;
+        vs->err = -EINVAL;
         goto out;
     }
     vs->sg = cap_sg(vs->sg, vs->count, &vs->cnt);
@@ -2364,13 +2324,31 @@ static void v9fs_write(V9fsState *s, V9fsPDU *pdu)
         if (vs->len > 0) {
             vs->off += vs->len;
         }
-        err = vs->len;
-        v9fs_write_post_pwritev(s, vs, err);
+        vs->err = vs->len;
     }
-    return;
 out:
-    complete_pdu(s, vs->pdu, err);
-    qemu_free(vs);
+    v9fs_async_helper_done(v9fs_write_do_complete, vs);
+}
+
+static void v9fs_write(V9fsState *s, V9fsPDU *pdu)
+{
+    V9fsWriteState *vs;
+
+    vs = qemu_malloc(sizeof(*vs));
+
+    vs->pdu = pdu;
+    vs->offset = 7;
+    vs->sg = vs->iov;
+    vs->total = 0;
+    vs->len = 0;
+    vs->s = s;
+
+    pdu_unmarshal(vs->pdu, vs->offset, "dqdv", &vs->fid, &vs->off, &vs->count,
+                  vs->sg, &vs->cnt);
+
+    vs->work.func = v9fs_write_worker;
+    submit_threadlet(&vs->work);
+    return;
 }
 
 static void v9fs_create_post_getiounit(V9fsState *s, V9fsCreateState *vs)
diff --git a/hw/virtio-9p.h b/hw/virtio-9p.h
index 5c6bf74..78d35b5 100644
--- a/hw/virtio-9p.h
+++ b/hw/virtio-9p.h
@@ -351,6 +351,10 @@ typedef struct V9fsWriteState {
     struct iovec iov[128]; /* FIXME: bad, bad, bad */
     struct iovec *sg;
     int cnt;
+    V9fsState *s;
+    int32_t fid;
+    int32_t err;
+    ThreadletWork work;
 } V9fsWriteState;
 
 typedef struct V9fsRemoveState {