From 5b6e021bc56ffa305bfd68a23d7709df6856ec08 Mon Sep 17 00:00:00 2001

From: Alon Levy <alevy@redhat.com>

Date: Tue, 22 Mar 2011 12:28:00 +0200

Subject: [PATCH] spice-qemu-char.c: remove intermediate buffer

BZ: 672191

upstream: not submitted (explained below)

virtio-serial's buffer is valid when it calls us, and we don't

access it otherwise: vmc_read is only called in response to wakeup,

or else we set datalen=0 and throttle. Then vmc_read is called back,

we return 0 (not accessing the buffer) and set the timer to unthrottle.

Also make datalen int and not ssize_t (to fit spice_chr_write signature).

This relied on the previous patch that introduces throttling, which

can't go upstream right now as explained in that patch.

---

 spice-qemu-char.c | 18 ++++++------------

 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/spice-qemu-char.c b/spice-qemu-char.c

index fba2bfb..ef44bc0 100644

--- a/spice-qemu-char.c

+++ b/spice-qemu-char.c

@@ -23,9 +23,8 @@ typedef struct SpiceCharDriver {

     SpiceCharDeviceInstance     sin;

     char                  *subtype;

     bool                  active;

-    uint8_t               *buffer;

-    uint8_t               *datapos;

-    ssize_t               bufsize, datalen;

+    const uint8_t         *datapos;

+    int                   datalen;

     uint32_t              debug;

     QEMUTimer             *unblock_timer;

 } SpiceCharDriver;

@@ -69,7 +68,7 @@ static int vmc_read(SpiceCharDeviceInstance *sin, uint8_t *buf, int len)

     SpiceCharDriver *scd = container_of(sin, SpiceCharDriver, sin);

     int bytes = MIN(len, scd->datalen);

-    dprintf(scd, 2, "%s: %p %d/%d/%zd\n", __func__, scd->datapos, len, bytes, scd->datalen);

+    dprintf(scd, 2, "%s: %p %d/%d/%d\n", __func__, scd->datapos, len, bytes, scd->datalen);

     if (bytes > 0) {

         memcpy(buf, scd->datapos, bytes);

         scd->datapos += bytes;

@@ -161,18 +160,13 @@ static int spice_chr_write(CharDriverState *chr, const uint8_t *buf, int len)

     dprintf(s, 2, "%s: %d\n", __func__, len);

     vmc_register_interface(s);

     assert(s->datalen == 0);

-    if (s->bufsize < len) {

-        s->bufsize = len;

-        s->buffer = g_realloc(s->buffer, s->bufsize);

-    }

-    memcpy(s->buffer, buf, len);

-    s->datapos = s->buffer;

+    s->datapos = buf;

     s->datalen = len;

     spice_server_char_device_wakeup(&s->sin);

     read_bytes = len - s->datalen;

     if (read_bytes != len) {

-        dprintf(s, 1, "%s: throttling: %d < %d (%zd)\n", __func__,

-                read_bytes, len, s->bufsize);

+        dprintf(s, 1, "%s: throttling: %d < %d\n", __func__,

+                read_bytes, len);

         s->chr->write_blocked = true;

         /* We'll get passed in the unconsumed data with the next call */

         s->datalen = 0;

-- 

1.7.11.2