9pfs: introduce init_out/in_iov_from_pdu

Not all 9pfs transports share memory between request and response. For
those who don't, it is necessary to know how much memory is required in
the response.

Split the existing init_iov_from_pdu function in two:
init_out_iov_from_pdu (for writes) and init_in_iov_from_pdu (for reads).
init_in_iov_from_pdu takes an additional size parameter to specify the
memory required for the response message.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index f9acd632596f07a42e327ef73ab6d82e2a394553..97c2926aae50bd61c31b74074618c76d0b02025c 100644 (file)
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1652,7 +1652,11 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
     struct iovec *iov;
     unsigned int niov;
 
-    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
+    if (is_write) {
+        pdu->s->transport->init_out_iov_from_pdu(pdu, &iov, &niov);
+    } else {
+        pdu->s->transport->init_in_iov_from_pdu(pdu, &iov, &niov, size);
+    }
 
     qemu_iovec_init_external(&elem, iov, niov);
     qemu_iovec_init(qiov, niov);

diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
index c8c9aa89093a089bdd422c1a6ea68866744301fc..4c4feafa2e97830d2b72dbd661a9f0a0584a0ae4 100644 (file)
--- a/hw/9pfs/9p.h
+++ b/hw/9pfs/9p.h
@@ -349,8 +349,10 @@ struct V9fsTransport {
                                 va_list ap);
     ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt,
                                   va_list ap);
-    void        (*init_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
-                                     unsigned int *pniov, bool is_write);
+    void        (*init_in_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
+                                        unsigned int *pniov, size_t size);
+    void        (*init_out_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
+                                         unsigned int *pniov);
     void        (*push_and_notify)(V9fsPDU *pdu);
 };
 

diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
index 273425b9d136b3fe1a83db4fcbc4897d5fd49a3b..27a4a32f5c4c99ebebd46a7c1defb7f1dac3ed80 100644 (file)
--- a/hw/9pfs/virtio-9p-device.c
+++ b/hw/9pfs/virtio-9p-device.c
@@ -171,26 +171,34 @@ static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
     return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
 }
 
-static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
-                                     unsigned int *pniov, bool is_write)
+/* The size parameter is used by other transports. Do not drop it. */
+static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
+                                        unsigned int *pniov, size_t size)
 {
     V9fsState *s = pdu->s;
     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
     VirtQueueElement *elem = v->elems[pdu->idx];
 
-    if (is_write) {
-        *piov = elem->out_sg;
-        *pniov = elem->out_num;
-    } else {
-        *piov = elem->in_sg;
-        *pniov = elem->in_num;
-    }
+    *piov = elem->in_sg;
+    *pniov = elem->in_num;
+}
+
+static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
+                                         unsigned int *pniov)
+{
+    V9fsState *s = pdu->s;
+    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
+    VirtQueueElement *elem = v->elems[pdu->idx];
+
+    *piov = elem->out_sg;
+    *pniov = elem->out_num;
 }
 
 static const struct V9fsTransport virtio_9p_transport = {
     .pdu_vmarshal = virtio_pdu_vmarshal,
     .pdu_vunmarshal = virtio_pdu_vunmarshal,
-    .init_iov_from_pdu = virtio_init_iov_from_pdu,
+    .init_in_iov_from_pdu = virtio_init_in_iov_from_pdu,
+    .init_out_iov_from_pdu = virtio_init_out_iov_from_pdu,
     .push_and_notify = virtio_9p_push_and_notify,
 };