[RFC 2/3] drm/msm: Rework get_comm_cmdline() helper

[Rob Clark <robdclark@gmail.com>]

From: Rob Clark <robdclark@chromium.org>

Make it work in terms of ctx so that it can be re-used for fdinfo.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/msm/adreno/adreno_gpu.c |  4 ++--
 drivers/gpu/drm/msm/msm_drv.c           |  2 ++
 drivers/gpu/drm/msm/msm_gpu.c           | 13 ++++++-------
 drivers/gpu/drm/msm/msm_gpu.h           | 12 ++++++++++--
 drivers/gpu/drm/msm/msm_submitqueue.c   |  1 +
 5 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index bb38e728864d..43c4e1fea83f 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -412,7 +412,7 @@ int adreno_set_param(struct msm_gpu *gpu, struct msm_file_private *ctx,
 		/* Ensure string is null terminated: */
 		str[len] = '\0';
 
-		mutex_lock(&gpu->lock);
+		mutex_lock(&ctx->lock);
 
 		if (param == MSM_PARAM_COMM) {
 			paramp = &ctx->comm;
@@ -423,7 +423,7 @@ int adreno_set_param(struct msm_gpu *gpu, struct msm_file_private *ctx,
 		kfree(*paramp);
 		*paramp = str;
 
-		mutex_unlock(&gpu->lock);
+		mutex_unlock(&ctx->lock);
 
 		return 0;
 	}
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 3d73b98d6a9c..ca0e89e46e13 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -581,6 +581,8 @@ static int context_init(struct drm_device *dev, struct drm_file *file)
 	rwlock_init(&ctx->queuelock);
 
 	kref_init(&ctx->ref);
+	ctx->pid = get_pid(task_pid(current));
+	mutex_init(&ctx->lock);
 	msm_submitqueue_init(dev, ctx);
 
 	ctx->aspace = msm_gpu_create_private_address_space(priv->gpu, current);
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index c403912d13ab..f0f4f845c32d 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -327,18 +327,17 @@ find_submit(struct msm_ringbuffer *ring, uint32_t fence)
 
 static void retire_submits(struct msm_gpu *gpu);
 
-static void get_comm_cmdline(struct msm_gem_submit *submit, char **comm, char **cmd)
+static void get_comm_cmdline(struct msm_file_private *ctx, char **comm, char **cmd)
 {
-	struct msm_file_private *ctx = submit->queue->ctx;
 	struct task_struct *task;
 
-	WARN_ON(!mutex_is_locked(&submit->gpu->lock));
-
 	/* Note that kstrdup will return NULL if argument is NULL: */
+	mutex_lock(&ctx->lock);
 	*comm = kstrdup(ctx->comm, GFP_KERNEL);
 	*cmd  = kstrdup(ctx->cmdline, GFP_KERNEL);
+	mutex_unlock(&ctx->lock);
 
-	task = get_pid_task(submit->pid, PIDTYPE_PID);
+	task = get_pid_task(ctx->pid, PIDTYPE_PID);
 	if (!task)
 		return;
 
@@ -372,7 +371,7 @@ static void recover_worker(struct kthread_work *work)
 		if (submit->aspace)
 			submit->aspace->faults++;
 
-		get_comm_cmdline(submit, &comm, &cmd);
+		get_comm_cmdline(submit->queue->ctx, &comm, &cmd);
 
 		if (comm && cmd) {
 			DRM_DEV_ERROR(dev->dev, "%s: offending task: %s (%s)\n",
@@ -460,7 +459,7 @@ static void fault_worker(struct kthread_work *work)
 		goto resume_smmu;
 
 	if (submit) {
-		get_comm_cmdline(submit, &comm, &cmd);
+		get_comm_cmdline(submit->queue->ctx, &comm, &cmd);
 
 		/*
 		 * When we get GPU iova faults, we can get 1000s of them,
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 7a4fa1b8655b..b2023a42116b 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -377,17 +377,25 @@ struct msm_file_private {
 	 */
 	int sysprof;
 
+	/** @pid: Process that opened this file. */
+	struct pid *pid;
+
+	/**
+	 * lock: Protects comm and cmdline
+	 */
+	struct mutex lock;
+
 	/**
 	 * comm: Overridden task comm, see MSM_PARAM_COMM
 	 *
-	 * Accessed under msm_gpu::lock
+	 * Accessed under msm_file_private::lock
 	 */
 	char *comm;
 
 	/**
 	 * cmdline: Overridden task cmdline, see MSM_PARAM_CMDLINE
 	 *
-	 * Accessed under msm_gpu::lock
+	 * Accessed under msm_file_private::lock
 	 */
 	char *cmdline;
 
diff --git a/drivers/gpu/drm/msm/msm_submitqueue.c b/drivers/gpu/drm/msm/msm_submitqueue.c
index 0e803125a325..0444ba04fa06 100644
--- a/drivers/gpu/drm/msm/msm_submitqueue.c
+++ b/drivers/gpu/drm/msm/msm_submitqueue.c
@@ -61,6 +61,7 @@ void __msm_file_private_destroy(struct kref *kref)
 	}
 
 	msm_gem_address_space_put(ctx->aspace);
+	put_pid(ctx->pid);
 	kfree(ctx->comm);
 	kfree(ctx->cmdline);
 	kfree(ctx);
-- 
2.39.2