[PATCH v1 4/6] dma-buf: Acquire wait-wound context on attachment
From: Dmitry Osipenko
Date: Thu Jul 14 2022 - 20:53:43 EST
Intel i915 GPU driver uses wait-wound mutex to lock multiple GEMs on the
attachment to the i915 dma-buf. In order to let all drivers utilize shared
wait-wound context during attachment in a general way, make dma-buf core to
acquire the ww context internally for the attachment operation and update
i915 driver to use the importer's ww context instead of the internal one.
>From now on all dma-buf exporters shall use the importer's ww context for
the attachment operation.
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
---
drivers/dma-buf/dma-buf.c | 8 +++++-
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 2 +-
.../gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_object.h | 6 ++---
drivers/gpu/drm/i915/i915_gem_evict.c | 2 +-
drivers/gpu/drm/i915/i915_gem_ww.c | 26 +++++++++++++++----
drivers/gpu/drm/i915/i915_gem_ww.h | 15 +++++++++--
7 files changed, 47 insertions(+), 14 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 0ee588276534..37545ecb845a 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -807,6 +807,8 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,
* Optionally this calls &dma_buf_ops.attach to allow device-specific attach
* functionality.
*
+ * Exporters shall use ww_ctx acquired by this function.
+ *
* Returns:
*
* A pointer to newly created &dma_buf_attachment on success, or a negative
@@ -822,6 +824,7 @@ dma_buf_dynamic_attach_unlocked(struct dma_buf *dmabuf, struct device *dev,
void *importer_priv)
{
struct dma_buf_attachment *attach;
+ struct ww_acquire_ctx ww_ctx;
int ret;
if (WARN_ON(!dmabuf || !dev))
@@ -841,7 +844,8 @@ dma_buf_dynamic_attach_unlocked(struct dma_buf *dmabuf, struct device *dev,
attach->importer_ops = importer_ops;
attach->importer_priv = importer_priv;
- dma_resv_lock(dmabuf->resv, NULL);
+ ww_acquire_init(&ww_ctx, &reservation_ww_class);
+ dma_resv_lock(dmabuf->resv, &ww_ctx);
if (dmabuf->ops->attach) {
ret = dmabuf->ops->attach(dmabuf, attach);
@@ -876,11 +880,13 @@ dma_buf_dynamic_attach_unlocked(struct dma_buf *dmabuf, struct device *dev,
}
dma_resv_unlock(dmabuf->resv);
+ ww_acquire_fini(&ww_ctx);
return attach;
err_attach:
dma_resv_unlock(attach->dmabuf->resv);
+ ww_acquire_fini(&ww_ctx);
kfree(attach);
return ERR_PTR(ret);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index c199bf71c373..9173f0232b16 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -173,7 +173,7 @@ static int i915_gem_dmabuf_attach(struct dma_buf *dmabuf,
if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM))
return -EOPNOTSUPP;
- for_i915_gem_ww(&ww, err, true) {
+ for_i915_dmabuf_ww(&ww, dmabuf, err, true) {
err = i915_gem_object_migrate(obj, &ww, INTEL_REGION_SMEM);
if (err)
continue;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 30fe847c6664..ad7d602fc43a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -3409,7 +3409,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
goto err_vma;
}
- ww_acquire_done(&eb.ww.ctx);
+ ww_acquire_done(eb.ww.ctx);
eb_capture_stage(&eb);
out_fence = eb_requests_create(&eb, in_fence, out_fence_fd);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index e11d82a9f7c3..5ae38f94a5c7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -178,9 +178,9 @@ static inline int __i915_gem_object_lock(struct drm_i915_gem_object *obj,
int ret;
if (intr)
- ret = dma_resv_lock_interruptible(obj->base.resv, ww ? &ww->ctx : NULL);
+ ret = dma_resv_lock_interruptible(obj->base.resv, ww ? ww->ctx : NULL);
else
- ret = dma_resv_lock(obj->base.resv, ww ? &ww->ctx : NULL);
+ ret = dma_resv_lock(obj->base.resv, ww ? ww->ctx : NULL);
if (!ret && ww) {
i915_gem_object_get(obj);
@@ -216,7 +216,7 @@ static inline bool i915_gem_object_trylock(struct drm_i915_gem_object *obj,
if (!ww)
return dma_resv_trylock(obj->base.resv);
else
- return ww_mutex_trylock(&obj->base.resv->lock, &ww->ctx);
+ return ww_mutex_trylock(&obj->base.resv->lock, ww->ctx);
}
static inline void i915_gem_object_unlock(struct drm_i915_gem_object *obj)
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index f025ee4fa526..047f72e32d47 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -458,7 +458,7 @@ int i915_gem_evict_vm(struct i915_address_space *vm, struct i915_gem_ww_ctx *ww)
* need the object ref.
*/
if (dying_vma(vma) ||
- (ww && (dma_resv_locking_ctx(vma->obj->base.resv) == &ww->ctx))) {
+ (ww && (dma_resv_locking_ctx(vma->obj->base.resv) == ww->ctx))) {
__i915_vma_pin(vma);
list_add(&vma->evict_link, &locked_eviction_list);
continue;
diff --git a/drivers/gpu/drm/i915/i915_gem_ww.c b/drivers/gpu/drm/i915/i915_gem_ww.c
index 3f6ff139478e..c47898993c7d 100644
--- a/drivers/gpu/drm/i915/i915_gem_ww.c
+++ b/drivers/gpu/drm/i915/i915_gem_ww.c
@@ -6,12 +6,20 @@
#include "i915_gem_ww.h"
#include "gem/i915_gem_object.h"
-void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ww, bool intr)
+void i915_gem_ww_ctx_prep(struct i915_gem_ww_ctx *ww,
+ struct ww_acquire_ctx *ww_ctx,
+ bool intr)
{
- ww_acquire_init(&ww->ctx, &reservation_ww_class);
INIT_LIST_HEAD(&ww->obj_list);
ww->intr = intr;
ww->contended = NULL;
+ ww->ctx = ww_ctx;
+}
+
+void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ww, bool intr)
+{
+ ww_acquire_init(&ww->ww_ctx, &reservation_ww_class);
+ i915_gem_ww_ctx_prep(ww, &ww->ww_ctx, intr);
}
static void i915_gem_ww_ctx_unlock_all(struct i915_gem_ww_ctx *ww)
@@ -36,7 +44,15 @@ void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ww)
{
i915_gem_ww_ctx_unlock_all(ww);
WARN_ON(ww->contended);
- ww_acquire_fini(&ww->ctx);
+
+ if (ww->ctx == &ww->ww_ctx)
+ ww_acquire_fini(ww->ctx);
+}
+
+void i915_gem_ww_ctx_fini2(struct i915_gem_ww_ctx *ww)
+{
+ i915_gem_ww_ctx_unlock_all(ww);
+ WARN_ON(ww->contended);
}
int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ww)
@@ -48,9 +64,9 @@ int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ww)
i915_gem_ww_ctx_unlock_all(ww);
if (ww->intr)
- ret = dma_resv_lock_slow_interruptible(ww->contended->base.resv, &ww->ctx);
+ ret = dma_resv_lock_slow_interruptible(ww->contended->base.resv, ww->ctx);
else
- dma_resv_lock_slow(ww->contended->base.resv, &ww->ctx);
+ dma_resv_lock_slow(ww->contended->base.resv, ww->ctx);
if (!ret)
list_add_tail(&ww->contended->obj_link, &ww->obj_list);
diff --git a/drivers/gpu/drm/i915/i915_gem_ww.h b/drivers/gpu/drm/i915/i915_gem_ww.h
index 86f0fe343de6..e9b0fd4debbf 100644
--- a/drivers/gpu/drm/i915/i915_gem_ww.h
+++ b/drivers/gpu/drm/i915/i915_gem_ww.h
@@ -8,13 +8,17 @@
#include <drm/drm_drv.h>
struct i915_gem_ww_ctx {
- struct ww_acquire_ctx ctx;
+ struct ww_acquire_ctx *ctx;
+ struct ww_acquire_ctx ww_ctx;
struct list_head obj_list;
struct drm_i915_gem_object *contended;
bool intr;
};
-void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ctx, bool intr);
+void i915_gem_ww_ctx_prep(struct i915_gem_ww_ctx *ww,
+ struct ww_acquire_ctx *ww_ctx,
+ bool intr);
+void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ww, bool intr);
void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ctx);
int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ctx);
void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj);
@@ -38,4 +42,11 @@ static inline int __i915_gem_ww_fini(struct i915_gem_ww_ctx *ww, int err)
for (i915_gem_ww_ctx_init(_ww, _intr), (_err) = -EDEADLK; \
(_err) == -EDEADLK; \
(_err) = __i915_gem_ww_fini(_ww, _err))
+
+#define for_i915_dmabuf_ww(_ww, _dmabuf, _err, _intr) \
+ for (i915_gem_ww_ctx_prep(_ww, dma_resv_locking_ctx((_dmabuf)->resv), _intr), \
+ (_err) = -EDEADLK; \
+ (_err) == -EDEADLK; \
+ (_err) = __i915_gem_ww_fini(_ww, _err))
+
#endif
--
2.36.1