drm: convert crtc and connection_mutex to ww_mutex (v5)
For atomic, it will be quite necessary to not need to care so much
about locking order. And 'state' gives us a convenient place to stash a
ww_ctx for any sort of update that needs to grab multiple crtc locks.
Because we will want to eventually make locking even more fine grained
(giving locks to planes, connectors, etc), split out drm_modeset_lock
and drm_modeset_acquire_ctx to track acquired locks.
Atomic will use this to keep track of which locks have been acquired
in a transaction.
v1: original
v2: remove a few things not needed until atomic, for now
v3: update for v3 of connection_mutex patch..
v4: squash in docbook
v5: doc tweaks/fixes
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index f3b98d4..43735f3 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -37,6 +37,7 @@
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include <drm/drm_fourcc.h>
+#include <drm/drm_modeset_lock.h>
#include "drm_crtc_internal.h"
@@ -50,14 +51,42 @@
*/
void drm_modeset_lock_all(struct drm_device *dev)
{
- struct drm_crtc *crtc;
+ struct drm_mode_config *config = &dev->mode_config;
+ struct drm_modeset_acquire_ctx *ctx;
+ int ret;
- mutex_lock(&dev->mode_config.mutex);
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (WARN_ON(!ctx))
+ return;
- mutex_lock(&dev->mode_config.connection_mutex);
+ mutex_lock(&config->mutex);
- list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
- mutex_lock_nest_lock(&crtc->mutex, &dev->mode_config.mutex);
+ drm_modeset_acquire_init(ctx, 0);
+
+retry:
+ ret = drm_modeset_lock(&config->connection_mutex, ctx);
+ if (ret)
+ goto fail;
+ ret = drm_modeset_lock_all_crtcs(dev, ctx);
+ if (ret)
+ goto fail;
+
+ WARN_ON(config->acquire_ctx);
+
+ /* now we hold the locks, so now that it is safe, stash the
+ * ctx for drm_modeset_unlock_all():
+ */
+ config->acquire_ctx = ctx;
+
+ drm_warn_on_modeset_not_all_locked(dev);
+
+ return;
+
+fail:
+ if (ret == -EDEADLK) {
+ drm_modeset_backoff(ctx);
+ goto retry;
+ }
}
EXPORT_SYMBOL(drm_modeset_lock_all);
@@ -69,12 +98,17 @@
*/
void drm_modeset_unlock_all(struct drm_device *dev)
{
- struct drm_crtc *crtc;
+ struct drm_mode_config *config = &dev->mode_config;
+ struct drm_modeset_acquire_ctx *ctx = config->acquire_ctx;
- list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
- mutex_unlock(&crtc->mutex);
+ if (WARN_ON(!ctx))
+ return;
- mutex_unlock(&dev->mode_config.connection_mutex);
+ config->acquire_ctx = NULL;
+ drm_modeset_drop_locks(ctx);
+ drm_modeset_acquire_fini(ctx);
+
+ kfree(ctx);
mutex_unlock(&dev->mode_config.mutex);
}
@@ -95,9 +129,9 @@
return;
list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
- WARN_ON(!mutex_is_locked(&crtc->mutex));
+ WARN_ON(!drm_modeset_is_locked(&crtc->mutex));
- WARN_ON(!mutex_is_locked(&dev->mode_config.connection_mutex));
+ WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
}
EXPORT_SYMBOL(drm_warn_on_modeset_not_all_locked);
@@ -671,6 +705,8 @@
}
EXPORT_SYMBOL(drm_framebuffer_remove);
+DEFINE_WW_CLASS(crtc_ww_class);
+
/**
* drm_crtc_init_with_planes - Initialise a new CRTC object with
* specified primary and cursor planes.
@@ -690,6 +726,7 @@
void *cursor,
const struct drm_crtc_funcs *funcs)
{
+ struct drm_mode_config *config = &dev->mode_config;
int ret;
crtc->dev = dev;
@@ -697,8 +734,9 @@
crtc->invert_dimensions = false;
drm_modeset_lock_all(dev);
- mutex_init(&crtc->mutex);
- mutex_lock_nest_lock(&crtc->mutex, &dev->mode_config.mutex);
+ drm_modeset_lock_init(&crtc->mutex);
+ /* dropped by _unlock_all(): */
+ drm_modeset_lock(&crtc->mutex, config->acquire_ctx);
ret = drm_mode_object_get(dev, &crtc->base, DRM_MODE_OBJECT_CRTC);
if (ret)
@@ -706,8 +744,8 @@
crtc->base.properties = &crtc->properties;
- list_add_tail(&crtc->head, &dev->mode_config.crtc_list);
- dev->mode_config.num_crtc++;
+ list_add_tail(&crtc->head, &config->crtc_list);
+ config->num_crtc++;
crtc->primary = primary;
if (primary)
@@ -735,6 +773,8 @@
kfree(crtc->gamma_store);
crtc->gamma_store = NULL;
+ drm_modeset_lock_fini(&crtc->mutex);
+
drm_mode_object_put(dev, &crtc->base);
list_del(&crtc->head);
dev->mode_config.num_crtc--;
@@ -1798,7 +1838,7 @@
DRM_DEBUG_KMS("[CONNECTOR:%d:?]\n", out_resp->connector_id);
mutex_lock(&dev->mode_config.mutex);
- mutex_lock(&dev->mode_config.connection_mutex);
+ drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
connector = drm_connector_find(dev, out_resp->connector_id);
if (!connector) {
@@ -1897,7 +1937,7 @@
out_resp->count_encoders = encoders_count;
out:
- mutex_unlock(&dev->mode_config.connection_mutex);
+ drm_modeset_unlock(&dev->mode_config.connection_mutex);
mutex_unlock(&dev->mode_config.mutex);
return ret;
@@ -2481,7 +2521,7 @@
return -ENOENT;
}
- mutex_lock(&crtc->mutex);
+ drm_modeset_lock(&crtc->mutex, NULL);
if (req->flags & DRM_MODE_CURSOR_BO) {
if (!crtc->funcs->cursor_set && !crtc->funcs->cursor_set2) {
ret = -ENXIO;
@@ -2505,7 +2545,7 @@
}
}
out:
- mutex_unlock(&crtc->mutex);
+ drm_modeset_unlock(&crtc->mutex);
return ret;
@@ -4198,7 +4238,7 @@
if (!crtc)
return -ENOENT;
- mutex_lock(&crtc->mutex);
+ drm_modeset_lock(&crtc->mutex, NULL);
if (crtc->primary->fb == NULL) {
/* The framebuffer is currently unbound, presumably
* due to a hotplug event, that userspace has not
@@ -4282,7 +4322,7 @@
drm_framebuffer_unreference(fb);
if (old_fb)
drm_framebuffer_unreference(old_fb);
- mutex_unlock(&crtc->mutex);
+ drm_modeset_unlock(&crtc->mutex);
return ret;
}
@@ -4647,7 +4687,7 @@
void drm_mode_config_init(struct drm_device *dev)
{
mutex_init(&dev->mode_config.mutex);
- mutex_init(&dev->mode_config.connection_mutex);
+ drm_modeset_lock_init(&dev->mode_config.connection_mutex);
mutex_init(&dev->mode_config.idr_mutex);
mutex_init(&dev->mode_config.fb_lock);
INIT_LIST_HEAD(&dev->mode_config.fb_list);
@@ -4747,5 +4787,6 @@
}
idr_destroy(&dev->mode_config.crtc_idr);
+ drm_modeset_lock_fini(&dev->mode_config.connection_mutex);
}
EXPORT_SYMBOL(drm_mode_config_cleanup);