[PATCH] Reference count shared driver mappings.

[Owain G. Ainsworth]

With MMIO it wasn't *such* a bit deal if we leaked the smallish mapping.
with FB it could be a larger deal. So instead of worrying about this,
reference count the mappings in the entity structure and unmap them when
no one cares anymore.

Prompted by a discussion with airlied
---
 src/radeon_driver.c |   12 ++++++++----
 src/radeon_probe.h  |    2 ++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/radeon_driver.c b/src/radeon_driver.c
index e138492..4c69eca 100644
--- a/src/radeon_driver.c
+++ b/src/radeon_driver.c
@@ -409,6 +409,7 @@ static Bool RADEONMapMMIO(ScrnInfoPtr pScrn)
     RADEONEntPtr pRADEONEnt = RADEONEntPriv(pScrn);
 
     if (pRADEONEnt->MMIO) {
+        pRADEONEnt->MMIO_cnt++;
         info->MMIO = pRADEONEnt->MMIO;
         return TRUE;
     }
@@ -441,6 +442,7 @@ static Bool RADEONMapMMIO(ScrnInfoPtr pScrn)
 #endif
 
     pRADEONEnt->MMIO = info->MMIO;
+    pRADEONEnt->MMIO_cnt = 1;
     return TRUE;
 }
 
@@ -452,8 +454,8 @@ static Bool RADEONUnmapMMIO(ScrnInfoPtr pScrn)
     RADEONInfoPtr  info = RADEONPTR(pScrn);
     RADEONEntPtr pRADEONEnt = RADEONEntPriv(pScrn);
 
-    if (info->IsPrimary || info->IsSecondary) {
-      /* never unmap on zaphod */
+    /* refcount for zaphod */
+    if (--pRADEONEnt->MMIO_cnt != 0) {
       info->MMIO = NULL;
       return TRUE;
     }
@@ -479,6 +481,7 @@ static Bool RADEONMapFB(ScrnInfoPtr pScrn)
     RADEONEntPtr pRADEONEnt = RADEONEntPriv(pScrn);
 
     if (pRADEONEnt->FB) {
+        pRADEONEnt->FB_cnt++;
         info->FB = pRADEONEnt->FB;
         return TRUE;
     }
@@ -515,6 +518,7 @@ static Bool RADEONMapFB(ScrnInfoPtr pScrn)
 #endif
 
     pRADEONEnt->FB = info->FB;
+    pRADEONEnt->FB_cnt = 1;
     return TRUE;
 }
 
@@ -524,8 +528,8 @@ static Bool RADEONUnmapFB(ScrnInfoPtr pScrn)
     RADEONInfoPtr  info = RADEONPTR(pScrn);
     RADEONEntPtr pRADEONEnt = RADEONEntPriv(pScrn);
 
-    if (info->IsPrimary || info->IsSecondary) {
-      /* never unmap on zaphod */
+    /* refcount for zaphod */
+    if (--pRADEONEnt->FB_cnt != 0) {
       info->FB = NULL;
       return TRUE;
     }
diff --git a/src/radeon_probe.h b/src/radeon_probe.h
index 405f5b4..2538df9 100644
--- a/src/radeon_probe.h
+++ b/src/radeon_probe.h
@@ -638,7 +638,9 @@ typedef struct
     RADEONSaveRec     SavedReg;         /* Original (text) mode              */
 
     void              *MMIO;            /* Map of MMIO region                */
+    int               *MMIO_cnt;        /* Map of FB region refcount         */
     void              *FB;              /* Map of FB region                  */
+    int               *FB_cnt;          /* Map of FB region refcount         */
     int fd;                             /* for sharing across zaphod heads   */
 } RADEONEntRec, *RADEONEntPtr;
 
-- 
1.6.5.7