From 404251dd0f5001c68f2c0b3d7b84530f3e1b5a40 Mon Sep 17 00:00:00 2001
From: Alexander Larsson <alexl@redhat.com>
Date: Mon, 13 Sep 2010 16:59:04 +0200
Subject: Protect all references to cmd_ring with cmd_sem

---
 display/res.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/display/res.c b/display/res.c
index 5dc72c5..a31832d 100644
--- a/display/res.c
+++ b/display/res.c
@@ -78,12 +78,10 @@ static BOOL SetClip(PDev *pdev, CLIPOBJ *clip, QXLDrawable *drawable);
 
 #define PUSH_CMD(pdev) do {                             \
     int notify;                                         \
-    EngAcquireSemaphore(pdev->Res->cmd_sem);            \
     SPICE_RING_PUSH(pdev->cmd_ring, notify);            \
     if (notify) {                                       \
         WRITE_PORT_UCHAR(pdev->notify_cmd_port, 0);     \
     }                                                   \
-    EngReleaseSemaphore(pdev->Res->cmd_sem);            \
 } while (0);
 
 #define PUSH_CURSOR_CMD(pdev) do {                      \
@@ -196,6 +194,7 @@ static void WaitForCursorRing(PDev* pdev)
     }
 }
 
+/* Called with cmd_sem held */
 static void WaitForCmdRing(PDev* pdev)
 {
     int wait;
@@ -581,11 +580,13 @@ void PushDrawable(PDev *pdev, QXLDrawable *drawable)
 {
     QXLCommand *cmd;
 
+    EngAcquireSemaphore(pdev->Res->cmd_sem);            \
     WaitForCmdRing(pdev);
     cmd = SPICE_RING_PROD_ITEM(pdev->cmd_ring);
     cmd->type = QXL_CMD_DRAW;
     cmd->data = PA(pdev, drawable, pdev->main_mem_slot);
     PUSH_CMD(pdev);
+    EngReleaseSemaphore(pdev->Res->cmd_sem);            \
 }
 
 static QXLSurfaceCmd *GetSurfaceCmd(PDev *pdev)
@@ -618,11 +619,13 @@ void PushSurfaceCmd(PDev *pdev, QXLSurfaceCmd *surface_cmd)
 {
     QXLCommand *cmd;
 
+    EngAcquireSemaphore(pdev->Res->cmd_sem);            \
     WaitForCmdRing(pdev);
     cmd = SPICE_RING_PROD_ITEM(pdev->cmd_ring);
     cmd->type = QXL_CMD_SURFACE;
     cmd->data = PA(pdev, surface_cmd, pdev->main_mem_slot);
     PUSH_CMD(pdev);
+    EngReleaseSemaphore(pdev->Res->cmd_sem);            \
 }
 
 
@@ -2426,11 +2429,13 @@ void UpdateArea(PDev *pdev, RECTL *area, UINT32 surface_id)
     updat_cmd->update_id = ++pdev->Res->update_id;
     updat_cmd->surface_id = surface_id;
 
+    EngAcquireSemaphore(pdev->Res->cmd_sem);            \
     WaitForCmdRing(pdev);
     cmd = SPICE_RING_PROD_ITEM(pdev->cmd_ring);
     cmd->type = QXL_CMD_UPDATE;
     cmd->data = PA(pdev, updat_cmd, pdev->main_mem_slot);
     PUSH_CMD(pdev);
+    EngReleaseSemaphore(pdev->Res->cmd_sem);            \
     do {
 #ifdef DBG
         {
-- 
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