[Mesa-dev] [PATCH 6/7] winsys/radeon: fix a race condition between winsys_create and winsys_destroy
Marek Olšák
maraeo at gmail.com
Tue Apr 8 17:15:02 PDT 2014
From: Marek Olšák <marek.olsak at amd.com>
This also hides the reference count from drivers.
---
src/gallium/drivers/r300/r300_screen.c | 2 +-
src/gallium/drivers/r600/r600_pipe.c | 2 +-
src/gallium/drivers/radeonsi/si_pipe.c | 2 +-
src/gallium/winsys/radeon/drm/radeon_drm_winsys.c | 30 +++++++++++++++++------
src/gallium/winsys/radeon/drm/radeon_drm_winsys.h | 1 +
src/gallium/winsys/radeon/drm/radeon_winsys.h | 20 ++++++---------
6 files changed, 33 insertions(+), 24 deletions(-)
diff --git a/src/gallium/drivers/r300/r300_screen.c b/src/gallium/drivers/r300/r300_screen.c
index 70c9cdf..8e601e3 100644
--- a/src/gallium/drivers/r300/r300_screen.c
+++ b/src/gallium/drivers/r300/r300_screen.c
@@ -552,7 +552,7 @@ static void r300_destroy_screen(struct pipe_screen* pscreen)
struct r300_screen* r300screen = r300_screen(pscreen);
struct radeon_winsys *rws = radeon_winsys(pscreen);
- if (rws && !radeon_winsys_unref(rws))
+ if (rws && !rws->unref(rws))
return;
pipe_mutex_destroy(r300screen->cmask_mutex);
diff --git a/src/gallium/drivers/r600/r600_pipe.c b/src/gallium/drivers/r600/r600_pipe.c
index 8d69358..18fde74 100644
--- a/src/gallium/drivers/r600/r600_pipe.c
+++ b/src/gallium/drivers/r600/r600_pipe.c
@@ -514,7 +514,7 @@ static void r600_destroy_screen(struct pipe_screen* pscreen)
if (rscreen == NULL)
return;
- if (!radeon_winsys_unref(rscreen->b.ws))
+ if (!rscreen->b.ws->unref(rscreen->b.ws))
return;
if (rscreen->global_pool) {
diff --git a/src/gallium/drivers/radeonsi/si_pipe.c b/src/gallium/drivers/radeonsi/si_pipe.c
index 09ec603..7dac287 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.c
+++ b/src/gallium/drivers/radeonsi/si_pipe.c
@@ -424,7 +424,7 @@ static void si_destroy_screen(struct pipe_screen* pscreen)
if (sscreen == NULL)
return;
- if (!radeon_winsys_unref(sscreen->b.ws))
+ if (!sscreen->b.ws->unref(sscreen->b.ws))
return;
r600_destroy_common_screen(&sscreen->b);
diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
index ebf7697..b968bd6 100644
--- a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
+++ b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
@@ -392,12 +392,6 @@ static void radeon_winsys_destroy(struct radeon_winsys *rws)
{
struct radeon_drm_winsys *ws = (struct radeon_drm_winsys*)rws;
- pipe_mutex_lock(fd_tab_mutex);
- if (fd_tab) {
- util_hash_table_remove(fd_tab, intptr_to_pointer(ws->fd));
- }
- pipe_mutex_unlock(fd_tab_mutex);
-
if (ws->thread) {
ws->kill_thread = 1;
pipe_semaphore_signal(&ws->cs_queued);
@@ -573,6 +567,25 @@ static PIPE_THREAD_ROUTINE(radeon_drm_cs_emit_ioctl, param)
DEBUG_GET_ONCE_BOOL_OPTION(thread, "RADEON_THREAD", TRUE)
static PIPE_THREAD_ROUTINE(radeon_drm_cs_emit_ioctl, param);
+static bool radeon_winsys_unref(struct radeon_winsys *ws)
+{
+ struct radeon_drm_winsys *rws = (struct radeon_drm_winsys*)ws;
+ bool destroy;
+
+ /* When the reference counter drops to zero, remove the fd from the table.
+ * This must happen while the mutex is locked, so that
+ * radeon_drm_winsys_create in another thread doesn't get the winsys
+ * from the table when the counter drops to 0. */
+ pipe_mutex_lock(fd_tab_mutex);
+
+ destroy = pipe_reference(&rws->reference, NULL);
+ if (destroy && fd_tab)
+ util_hash_table_remove(fd_tab, intptr_to_pointer(rws->fd));
+
+ pipe_mutex_unlock(fd_tab_mutex);
+ return destroy;
+}
+
PUBLIC struct radeon_winsys *radeon_drm_winsys_create(int fd)
{
struct radeon_drm_winsys *ws;
@@ -585,7 +598,7 @@ PUBLIC struct radeon_winsys *radeon_drm_winsys_create(int fd)
ws = util_hash_table_get(fd_tab, intptr_to_pointer(fd));
if (ws) {
pipe_mutex_unlock(fd_tab_mutex);
- pipe_reference(NULL, &ws->base.reference);
+ pipe_reference(NULL, &ws->reference);
return &ws->base;
}
@@ -616,9 +629,10 @@ PUBLIC struct radeon_winsys *radeon_drm_winsys_create(int fd)
}
/* init reference */
- pipe_reference_init(&ws->base.reference, 1);
+ pipe_reference_init(&ws->reference, 1);
/* Set functions. */
+ ws->base.unref = radeon_winsys_unref;
ws->base.destroy = radeon_winsys_destroy;
ws->base.query_info = radeon_query_info;
ws->base.cs_request_feature = radeon_cs_request_feature;
diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.h b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.h
index 1aa9cf4..18fe0ae 100644
--- a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.h
+++ b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.h
@@ -43,6 +43,7 @@ enum radeon_generation {
struct radeon_drm_winsys {
struct radeon_winsys base;
+ struct pipe_reference reference;
int fd; /* DRM file descriptor */
int num_cs; /* The number of command streams created. */
diff --git a/src/gallium/winsys/radeon/drm/radeon_winsys.h b/src/gallium/winsys/radeon/drm/radeon_winsys.h
index eeae724..485e925 100644
--- a/src/gallium/winsys/radeon/drm/radeon_winsys.h
+++ b/src/gallium/winsys/radeon/drm/radeon_winsys.h
@@ -232,14 +232,17 @@ enum radeon_feature_id {
struct radeon_winsys {
/**
- * Reference counting
+ * The screen object this winsys was created for
*/
- struct pipe_reference reference;
+ struct pipe_screen *screen;
/**
- * The screen object this winsys was created for
+ * Decrement the winsys reference count.
+ *
+ * \param ws The winsys this function is called for.
+ * \return True if the winsys and screen should be destroyed.
*/
- struct pipe_screen *screen;
+ bool (*unref)(struct radeon_winsys *ws);
/**
* Destroy this winsys.
@@ -568,15 +571,6 @@ struct radeon_winsys {
enum radeon_value_id value);
};
-/**
- * Decrement the winsys reference count.
- *
- * \param ws The winsys this function is called for.
- */
-static INLINE boolean radeon_winsys_unref(struct radeon_winsys *ws)
-{
- return pipe_reference(&ws->reference, NULL);
-}
static INLINE void radeon_emit(struct radeon_winsys_cs *cs, uint32_t value)
{
--
1.8.3.2
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