linux-kernel - [RFC 12/24] drm/msm: Split submit_pin

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Message-ID: <20241207161651.410556-13-robdclark@gmail.com>
Date: Sat,  7 Dec 2024 08:15:12 -0800
From: Rob Clark <robdclark@...il.com>
To: dri-devel@...ts.freedesktop.org
Cc: freedreno@...ts.freedesktop.org,
	linux-arm-msm@...r.kernel.org,
	Connor Abbott <cwabbott0@...il.com>,
	Akhil P Oommen <quic_akhilpo@...cinc.com>,
	Rob Clark <robdclark@...omium.org>,
	Rob Clark <robdclark@...il.com>,
	Abhinav Kumar <quic_abhinavk@...cinc.com>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
	Sean Paul <sean@...rly.run>,
	Marijn Suijten <marijn.suijten@...ainline.org>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	linux-kernel@...r.kernel.org (open list)
Subject: [RFC 12/24] drm/msm: Split submit_pin_objects()

From: Rob Clark <robdclark@...omium.org>

For VM_BIND, in the first step, we just want to get the backing pages,
but defer creating the vma until the map/unmap/ops are evaluated.

Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 drivers/gpu/drm/msm/msm_gem_submit.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index 8a4f4c403404..51c92fe1146f 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -292,12 +292,16 @@ static int submit_fence_sync(struct msm_gem_submit *submit)
 	return ret;
 }
 
-static int submit_pin_objects(struct msm_gem_submit *submit)
+static int submit_pin_vmas(struct msm_gem_submit *submit)
 {
-	struct msm_drm_private *priv = submit->dev->dev_private;
-	int i, ret = 0;
+	int ret = 0;
 
-	for (i = 0; i < submit->nr_bos; i++) {
+	/*
+	 * First loop, before holding the LRU lock, avoids holding the
+	 * LRU lock while calling msm_gem_pin_vma_locked (which could
+	 * trigger get_pages())
+	 */
+	for (int i = 0; i < submit->nr_bos; i++) {
 		struct drm_gem_object *obj = submit->bos[i].obj;
 		struct drm_gpuva *vma;
 
@@ -315,6 +319,13 @@ static int submit_pin_objects(struct msm_gem_submit *submit)
 		submit->bos[i].iova = vma->va.addr;
 	}
 
+	return ret;
+}
+
+static void submit_pin_objects(struct msm_gem_submit *submit)
+{
+	struct msm_drm_private *priv = submit->dev->dev_private;
+
 	/*
 	 * A second loop while holding the LRU lock (a) avoids acquiring/dropping
 	 * the LRU lock for each individual bo, while (b) avoiding holding the
@@ -323,14 +334,12 @@ static int submit_pin_objects(struct msm_gem_submit *submit)
 	 * could trigger deadlock with the shrinker).
 	 */
 	mutex_lock(&priv->lru.lock);
-	for (i = 0; i < submit->nr_bos; i++) {
+	for (int i = 0; i < submit->nr_bos; i++) {
 		msm_gem_pin_obj_locked(submit->bos[i].obj);
 	}
 	mutex_unlock(&priv->lru.lock);
 
 	submit->bos_pinned = true;
-
-	return ret;
 }
 
 static void submit_unpin_objects(struct msm_gem_submit *submit)
@@ -760,10 +769,12 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 			goto out;
 	}
 
-	ret = submit_pin_objects(submit);
+	ret = submit_pin_vmas(submit);
 	if (ret)
 		goto out;
 
+	submit_pin_objects(submit);
+
 	for (i = 0; i < args->nr_cmds; i++) {
 		struct drm_gem_object *obj;
 		uint64_t iova;
-- 
2.47.1