Hi.
Some clean up to code so it is better thread safety even tough it is not
100% without locking or atomic operations. (Now it works same way as intel
does recursion prevention)
Another adittion is to make debug output to check if DEBUG_SANITY is set.
Whole lock debugging is compiled out if there is NDEBUG set so there
wouldn't be need of passing debug parameters in release version.
Pauli
From 8452c3d4ef90f70d3c8640680bc07323816efd93 Mon Sep 17 00:00:00 2001
From: Pauli Nieminen <[email protected]>
Date: Thu, 30 Jul 2009 20:17:29 +0300
Subject: [PATCH] radeon: Add protection against recursive DRM locking.
Reference counting protects DRM lock call from recursive locking that would
cause hang. Code also adds optional debugging output for recursive call that
is compiled only if NDEBUG is not defined.
This code is not 100% thread safe because mesa doesn't include increment and
test atomic operation. There is built-in gcc functions but they are only
available from gcc 4.2.
---
.../drivers/dri/radeon/radeon_common_context.c | 1 +
.../drivers/dri/radeon/radeon_common_context.h | 1 +
src/mesa/drivers/dri/radeon/radeon_lock.c | 52 +++++++++++++++++++-
src/mesa/drivers/dri/radeon/radeon_lock.h | 12 ++++-
4 files changed, 63 insertions(+), 3 deletions(-)
diff --git a/src/mesa/drivers/dri/radeon/radeon_common_context.c b/src/mesa/drivers/dri/radeon/radeon_common_context.c
index 4e4eba5..b88270e 100644
--- a/src/mesa/drivers/dri/radeon/radeon_common_context.c
+++ b/src/mesa/drivers/dri/radeon/radeon_common_context.c
@@ -211,6 +211,7 @@ GLboolean radeonInitContext(radeonContextPtr radeon,
radeon->dri.screen = sPriv;
radeon->dri.hwContext = driContextPriv->hHWContext;
radeon->dri.hwLock = &sPriv->pSAREA->lock;
+ radeon->dri.hwLockCount = 0;
radeon->dri.fd = sPriv->fd;
radeon->dri.drmMinor = sPriv->drm_version.minor;
diff --git a/src/mesa/drivers/dri/radeon/radeon_common_context.h b/src/mesa/drivers/dri/radeon/radeon_common_context.h
index cd1986e..7b57282 100644
--- a/src/mesa/drivers/dri/radeon/radeon_common_context.h
+++ b/src/mesa/drivers/dri/radeon/radeon_common_context.h
@@ -365,6 +365,7 @@ struct radeon_dri_mirror {
drm_context_t hwContext;
drm_hw_lock_t *hwLock;
+ int hwLockCount;
int fd;
int drmMinor;
};
diff --git a/src/mesa/drivers/dri/radeon/radeon_lock.c b/src/mesa/drivers/dri/radeon/radeon_lock.c
index 5774f7e..72ef488 100644
--- a/src/mesa/drivers/dri/radeon/radeon_lock.c
+++ b/src/mesa/drivers/dri/radeon/radeon_lock.c
@@ -88,8 +88,34 @@ void radeonGetLock(radeonContextPtr rmesa, GLuint flags)
rmesa->lost_context = GL_TRUE;
}
-
-void radeon_lock_hardware(radeonContextPtr radeon)
+#ifndef NDEBUG
+struct lock_debug {
+ const char* function;
+ const char* file;
+ int line;
+};
+
+static struct lock_debug ldebug = {0};
+#endif
+
+#if 0
+/** TODO: use atomic operations for reference counting **/
+/** gcc 4.1 has builtin functios for this **/
+#define ATOMIC_INC_AND_FETCH(atomic) __sync_add_and_fetch(&atomic, 1)
+#define ATOMIC_DEC_AND_FETCH(atomic) __sync_sub_and_fetch(&atomic, 1)
+#else
+#define ATOMIC_ADD_AND_FETCH(atomic, value) (++atomic)
+#define ATOMIC_SUB_AND_FETCH(atomic, value) (--atomic)
+#endif
+
+
+void radeon_lock_hardware(radeonContextPtr radeon
+#ifndef NDEBUG
+ ,const char* function
+ ,const char* file
+ ,const int line
+#endif
+ )
{
char ret = 0;
struct radeon_framebuffer *rfb = NULL;
@@ -104,16 +130,38 @@ void radeon_lock_hardware(radeonContextPtr radeon)
}
if (!radeon->radeonScreen->driScreen->dri2.enabled) {
+ if (ATOMIC_INC_AND_FETCH(radeon->dri.hwLockCount) > 0)
+ {
+#ifndef NDEBUG
+ fprintf(stderr, "*** %d times of recursive call to %s ***\n"
+ "Original call was from %s (file: %s line: %d)\n"
+ "Now call is coming from %s (file: %s line: %d)\n"
+ , radeon->dri.hwLockCount, __FUNCTION__
+ , ldebug.function, ldebug.file, ldebug.line
+ , function, file, line
+ );
+#endif
+ return;
+ }
DRM_CAS(radeon->dri.hwLock, radeon->dri.hwContext,
(DRM_LOCK_HELD | radeon->dri.hwContext), ret );
if (ret)
radeonGetLock(radeon, 0);
+#ifndef NDEBUG
+ ldebug.function = function;
+ ldebug.file = file;
+ ldebug.line = line;
+#endif
}
}
void radeon_unlock_hardware(radeonContextPtr radeon)
{
if (!radeon->radeonScreen->driScreen->dri2.enabled) {
+ if (ATOMIC_DEC_AND_FETCH(radeon->dri.hwLockCount) > 0)
+ {
+ return;
+ }
DRM_UNLOCK( radeon->dri.fd,
radeon->dri.hwLock,
radeon->dri.hwContext );
diff --git a/src/mesa/drivers/dri/radeon/radeon_lock.h b/src/mesa/drivers/dri/radeon/radeon_lock.h
index 2817709..da5a5b4 100644
--- a/src/mesa/drivers/dri/radeon/radeon_lock.h
+++ b/src/mesa/drivers/dri/radeon/radeon_lock.h
@@ -48,12 +48,22 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
extern void radeonGetLock(radeonContextPtr rmesa, GLuint flags);
-void radeon_lock_hardware(radeonContextPtr rmesa);
+void radeon_lock_hardware(radeonContextPtr rmesa
+#ifndef NDEBUG
+ ,const char* function
+ ,const char* file
+ ,const int line
+#endif
+ );
void radeon_unlock_hardware(radeonContextPtr rmesa);
/* Lock the hardware and validate our state.
*/
+#ifdef NDEBUG
#define LOCK_HARDWARE( rmesa ) radeon_lock_hardware(rmesa)
+#else
+#define LOCK_HARDWARE( rmesa ) radeon_lock_hardware(rmesa, __FUNCTION__, __FILE__, __LINE__)
+#endif
#define UNLOCK_HARDWARE( rmesa ) radeon_unlock_hardware(rmesa)
#endif
--
1.6.3.3
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