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[Qemu-devel] [PATCH 11/17] iov: Introduce a new file for helpers around


From: Amit Shah
Subject: [Qemu-devel] [PATCH 11/17] iov: Introduce a new file for helpers around iovs, add iov_from_buf()
Date: Wed, 31 Mar 2010 13:04:02 +0530

The virtio-net code uses iov_fill() which fills an iov from a linear
buffer. The virtio-serial-bus code does something similar in an
open-coded function.

Create a new iov.c file that has iov_from_buf().

Convert virtio-net and virtio-serial-bus over to use this functionality.
virtio-net used ints to hold sizes, the new function is going to use
size_t types.

Later commits will add the opposite functionality -- going from an iov
to a linear buffer.

Signed-off-by: Amit Shah <address@hidden>
---
 Makefile.objs          |    1 +
 hw/iov.c               |   33 +++++++++++++++++++++++++++++++++
 hw/iov.h               |   16 ++++++++++++++++
 hw/virtio-net.c        |   20 +++-----------------
 hw/virtio-serial-bus.c |   15 +++++++--------
 5 files changed, 60 insertions(+), 25 deletions(-)
 create mode 100644 hw/iov.c
 create mode 100644 hw/iov.h

diff --git a/Makefile.objs b/Makefile.objs
index 233fbba..2ab09d7 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -129,6 +129,7 @@ user-obj-y += cutils.o cache-utils.o
 
 hw-obj-y =
 hw-obj-y += vl.o loader.o
+hw-obj-y += iov.o
 hw-obj-y += virtio.o virtio-console.o
 hw-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
 hw-obj-y += fw_cfg.o pci.o pci_host.o pcie_host.o
diff --git a/hw/iov.c b/hw/iov.c
new file mode 100644
index 0000000..07bd499
--- /dev/null
+++ b/hw/iov.c
@@ -0,0 +1,33 @@
+/*
+ * Helpers for getting linearized buffers from iov / filling buffers into iovs
+ *
+ * Copyright IBM, Corp. 2007, 2008
+ * Copyright (C) 2010 Red Hat, Inc.
+ *
+ * Author(s):
+ *  Anthony Liguori <address@hidden>
+ *  Amit Shah <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "iov.h"
+
+size_t iov_from_buf(struct iovec *iov, unsigned int iovcnt,
+                    const void *buf, size_t size)
+{
+    size_t offset;
+    unsigned int i;
+
+    offset = 0;
+    for (i = 0; offset < size && i < iovcnt; i++) {
+        size_t len;
+
+        len = MIN(iov[i].iov_len, size - offset);
+
+        memcpy(iov[i].iov_base, buf + offset, len);
+        offset += len;
+    }
+    return offset;
+}
diff --git a/hw/iov.h b/hw/iov.h
new file mode 100644
index 0000000..5e3e541
--- /dev/null
+++ b/hw/iov.h
@@ -0,0 +1,16 @@
+/*
+ * Helpers for getting linearized buffers from iov / filling buffers into iovs
+ *
+ * Copyright (C) 2010 Red Hat, Inc.
+ *
+ * Author(s):
+ *  Amit Shah <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qemu-common.h"
+
+size_t iov_from_buf(struct iovec *iov, unsigned int iovcnt,
+                    const void *buf, size_t size);
diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index be33c68..273e7f9 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -11,6 +11,7 @@
  *
  */
 
+#include "iov.h"
 #include "virtio.h"
 #include "net.h"
 #include "net/checksum.h"
@@ -423,21 +424,6 @@ static void work_around_broken_dhclient(struct 
virtio_net_hdr *hdr,
     }
 }
 
-static int iov_fill(struct iovec *iov, int iovcnt, const void *buf, int count)
-{
-    int offset, i;
-
-    offset = i = 0;
-    while (offset < count && i < iovcnt) {
-        int len = MIN(iov[i].iov_len, count - offset);
-        memcpy(iov[i].iov_base, buf + offset, len);
-        offset += len;
-        i++;
-    }
-
-    return offset;
-}
-
 static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt,
                           const void *buf, size_t size, size_t hdr_len)
 {
@@ -573,8 +559,8 @@ static ssize_t virtio_net_receive(VLANClientState *nc, 
const uint8_t *buf, size_
         }
 
         /* copy in packet.  ugh */
-        len = iov_fill(sg, elem.in_num,
-                       buf + offset, size - offset);
+        len = iov_from_buf(sg, elem.in_num,
+                           buf + offset, size - offset);
         total += len;
 
         /* signal other side */
diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index 236e300..ee45146 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -15,6 +15,7 @@
  * the COPYING file in the top-level directory.
  */
 
+#include "iov.h"
 #include "monitor.h"
 #include "qemu-queue.h"
 #include "sysbus.h"
@@ -84,27 +85,25 @@ static size_t write_to_port(VirtIOSerialPort *port,
 {
     VirtQueueElement elem;
     VirtQueue *vq;
-    size_t offset = 0;
-    size_t len = 0;
+    size_t offset;
 
     vq = port->ivq;
     if (!virtio_queue_ready(vq)) {
         return 0;
     }
 
+    offset = 0;
     while (offset < size) {
-        int i;
+        size_t len;
 
         if (!virtqueue_pop(vq, &elem)) {
             break;
         }
 
-        for (i = 0; offset < size && i < elem.in_num; i++) {
-            len = MIN(elem.in_sg[i].iov_len, size - offset);
+        len = iov_from_buf(elem.in_sg, elem.in_num,
+                           buf + offset, size - offset);
+        offset += len;
 
-            memcpy(elem.in_sg[i].iov_base, buf + offset, len);
-            offset += len;
-        }
         virtqueue_push(vq, &elem, len);
     }
 
-- 
1.6.2.5





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