[PATCH xserver] prime: clean up slave bo properly. (v3)

[Dave Airlie]

This is an ABI break, in that we now pass NULL to a function
that hasn't accepted it before.

Alex Goins had a different patch for this but it wasn't symmetrical,
it freed something in a very different place than it allocated it,
this attempts to retain symmetry in the releasing of the backing bo.

v2: use a new toplevel API, though it still passes NULL to something
that wasn't expecting it.
v3: pass -1 instead of 0.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 dix/pixmap.c                                     | 7 +++++++
 hw/xfree86/dri2/dri2.c                           | 1 +
 hw/xfree86/drivers/modesetting/driver.c          | 4 ++++
 hw/xfree86/drivers/modesetting/drmmode_display.c | 6 ++++++
 include/pixmap.h                                 | 3 +++
 randr/rrcrtc.c                                   | 2 ++
 6 files changed, 23 insertions(+)

diff --git a/dix/pixmap.c b/dix/pixmap.c
index 11d83fe..49267a1 100644
--- a/dix/pixmap.c
+++ b/dix/pixmap.c
@@ -132,6 +132,13 @@ FreePixmap(PixmapPtr pPixmap)
     free(pPixmap);
 }
 
+void PixmapUnshareSlavePixmap(PixmapPtr slave_pixmap)
+{
+     int ihandle = -1;
+     ScreenPtr pScreen = slave_pixmap->drawable.pScreen;
+     pScreen->SetSharedPixmapBacking(slave_pixmap, ((void *)(long)ihandle));
+}
+
 PixmapPtr PixmapShareToSlave(PixmapPtr pixmap, ScreenPtr slave)
 {
     PixmapPtr spix;
diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index d55be19..f80599f 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -859,6 +859,7 @@ DrawablePtr DRI2UpdatePrime(DrawablePtr pDraw, DRI2BufferPtr pDest)
         if (pPriv->prime_slave_pixmap->master_pixmap == mpix)
             return &pPriv->prime_slave_pixmap->drawable;
         else {
+            PixmapUnshareSlavePixmap(pPriv->prime_slave_pixmap);
             (*pPriv->prime_slave_pixmap->master_pixmap->drawable.pScreen->DestroyPixmap)(pPriv->prime_slave_pixmap->master_pixmap);
             (*slave->DestroyPixmap)(pPriv->prime_slave_pixmap);
             pPriv->prime_slave_pixmap = NULL;
diff --git a/hw/xfree86/drivers/modesetting/driver.c b/hw/xfree86/drivers/modesetting/driver.c
index cd59c06..1604044 100644
--- a/hw/xfree86/drivers/modesetting/driver.c
+++ b/hw/xfree86/drivers/modesetting/driver.c
@@ -1074,6 +1074,10 @@ msSetSharedPixmapBacking(PixmapPtr ppix, void *fd_handle)
     Bool ret;
     int ihandle = (int) (long) fd_handle;
 
+    if (ihandle == -1)
+        if (!ms->drmmode.reverse_prime_offload_mode)
+           return drmmode_SetSlaveBO(ppix, &ms->drmmode, ihandle, 0, 0);
+
     if (ms->drmmode.reverse_prime_offload_mode) {
         ret = glamor_back_pixmap_from_fd(ppix, ihandle,
                                          ppix->drawable.width,
diff --git a/hw/xfree86/drivers/modesetting/drmmode_display.c b/hw/xfree86/drivers/modesetting/drmmode_display.c
index 2cda523..5e104b8 100644
--- a/hw/xfree86/drivers/modesetting/drmmode_display.c
+++ b/hw/xfree86/drivers/modesetting/drmmode_display.c
@@ -214,6 +214,12 @@ drmmode_SetSlaveBO(PixmapPtr ppix,
 {
     msPixmapPrivPtr ppriv = msGetPixmapPriv(drmmode, ppix);
 
+    if (fd_handle == -1) {
+        dumb_bo_destroy(drmmode->fd, ppriv->backing_bo);
+        ppriv->backing_bo = NULL;
+        return TRUE;
+    }
+
     ppriv->backing_bo =
         dumb_get_bo_from_fd(drmmode->fd, fd_handle, pitch, size);
     if (!ppriv->backing_bo)
diff --git a/include/pixmap.h b/include/pixmap.h
index c6a7736..86b513d 100644
--- a/include/pixmap.h
+++ b/include/pixmap.h
@@ -115,6 +115,9 @@ extern _X_EXPORT void FreePixmap(PixmapPtr /*pPixmap */ );
 extern _X_EXPORT PixmapPtr
 PixmapShareToSlave(PixmapPtr pixmap, ScreenPtr slave);
 
+extern _X_EXPORT void
+PixmapUnshareSlavePixmap(PixmapPtr slave_pixmap);
+
 #define HAS_DIRTYTRACKING_ROTATION 1
 extern _X_EXPORT Bool
 PixmapStartDirtyTracking(PixmapPtr src,
diff --git a/randr/rrcrtc.c b/randr/rrcrtc.c
index 566a3db..5447133 100644
--- a/randr/rrcrtc.c
+++ b/randr/rrcrtc.c
@@ -373,6 +373,8 @@ rrDestroySharedPixmap(RRCrtcPtr crtc, PixmapPtr pPixmap) {
          * Unref the pixmap twice: once for the original reference, and once
          * for the reference implicitly added by PixmapShareToSlave.
          */
+        PixmapUnshareSlavePixmap(pPixmap);
+
         master->DestroyPixmap(pPixmap->master_pixmap);
         master->DestroyPixmap(pPixmap->master_pixmap);
     }
-- 
2.5.5