msm: kgsl: Fail if sysfs or debugfs initialization fails

While creating a new process struct for kgsl, clean up resources
and bail if sysfs or debugfs initialization fails. This prevents
errors further down the line.

CRs-fixed: 509931
Change-Id: If0857628a56eecf4855013aaf313de28ac9ad108
Signed-off-by: Harsh Vardhan Dwivedi <hdwivedi@codeaurora.org>
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>

drivers/gpu/msm/kgsl.c

@@ -755,7 +755,7 @@ static void kgsl_destroy_process_private(struct kref *kref)
 	list_del(&private->list);
 	mutex_unlock(&kgsl_driver.process_mutex);
 
-	if (private->kobj.parent)
+	if (private->kobj.state_in_sysfs)
 		kgsl_process_uninit_sysfs(private);
 	if (private->debug_root)
 		debugfs_remove_recursive(private->debug_root);
@@ -869,21 +869,23 @@ kgsl_get_process_private(struct kgsl_device_private *cur_dev_priv)
 
 		pt_name = task_tgid_nr(current);
 		private->pagetable = kgsl_mmu_getpagetable(mmu, pt_name);
-		if (private->pagetable == NULL) {
-			mutex_unlock(&private->process_private_mutex);
-			kgsl_put_process_private(cur_dev_priv->device,
-						private);
-			return NULL;
-		}
+		if (private->pagetable == NULL)
+			goto error;
 	}
 
-	kgsl_process_init_sysfs(private);
-	kgsl_process_init_debugfs(private);
+	if (kgsl_process_init_sysfs(cur_dev_priv->device, private))
+		goto error;
+	if (kgsl_process_init_debugfs(private))
+		goto error;
 
 done:
 	mutex_unlock(&private->process_private_mutex);
-
 	return private;
+
+error:
+	mutex_unlock(&private->process_private_mutex);
+	kgsl_put_process_private(cur_dev_priv->device, private);
+	return NULL;
 }
 
 int kgsl_close_device(struct kgsl_device *device)

drivers/gpu/msm/kgsl_debugfs.c

@@ -322,25 +322,53 @@ static const struct file_operations process_mem_fops = {
 	.release = single_release,
 };
 
-void
+
+/**
+ * kgsl_process_init_debugfs() - Initialize debugfs for a process
+ * @private: Pointer to process private structure created for the process
+ *
+ * @returns: 0 on success, error code otherwise
+ *
+ * kgsl_process_init_debugfs() is called at the time of creating the
+ * process struct when a process opens kgsl device for the first time.
+ * The function creates the debugfs files for the process. If debugfs is
+ * disabled in the kernel, we ignore that error and return as successful.
+ */
+int
 kgsl_process_init_debugfs(struct kgsl_process_private *private)
 {
 	unsigned char name[16];
-	struct dentry *mem_dentry;
+	int ret = 0;
+	struct dentry *dentry;
 
 	snprintf(name, sizeof(name), "%d", private->pid);
 
 	private->debug_root = debugfs_create_dir(name, proc_d_debugfs);
-	if (private->debug_root) {
-		private->debug_root->d_inode->i_uid = proc_d_debugfs->d_inode->i_uid;
-		private->debug_root->d_inode->i_gid = proc_d_debugfs->d_inode->i_gid;
-	}
-	mem_dentry = debugfs_create_file("mem", 0400, private->debug_root, private,
+
+	if (!private->debug_root)
+		return -EINVAL;
+
+	/*
+	 * debugfs_create_dir() and debugfs_create_file() both
+	 * return -ENODEV if debugfs is disabled in the kernel.
+	 * We make a distinction between these two functions
+	 * failing and debugfs being disabled in the kernel.
+	 * In the first case, we abort process private struct
+	 * creation, in the second we continue without any changes.
+	 * So if debugfs is disabled in kernel, return as
+	 * success.
+	 */
+	dentry = debugfs_create_file("mem", 0400, private->debug_root, private,
 			    &process_mem_fops);
-	if (mem_dentry) {
-		mem_dentry->d_inode->i_uid = proc_d_debugfs->d_inode->i_uid;
-		mem_dentry->d_inode->i_gid = proc_d_debugfs->d_inode->i_gid;
+
+	if (IS_ERR(dentry)) {
+		ret = PTR_ERR(dentry);
+
+		if (ret == -ENODEV)
+			ret = 0;
 	}
+
+	return ret;
 }
 
 void kgsl_core_debugfs_init(void)

drivers/gpu/msm/kgsl_debugfs.h

@@ -21,7 +21,7 @@ struct kgsl_process_private;
 void kgsl_core_debugfs_init(void);
 void kgsl_core_debugfs_close(void);
 
-void kgsl_device_debugfs_init(struct kgsl_device *device);
+int kgsl_device_debugfs_init(struct kgsl_device *device);
 
 extern struct dentry *kgsl_debugfs_dir;
 static inline struct dentry *kgsl_get_debugfs_dir(void)

drivers/gpu/msm/kgsl_sharedmem.c

@@ -170,17 +170,32 @@ kgsl_process_uninit_sysfs(struct kgsl_process_private *private)
 	kobject_put(&private->kobj);
 }
 
-void
-kgsl_process_init_sysfs(struct kgsl_process_private *private)
+/**
+ * kgsl_process_init_sysfs() - Initialize and create sysfs files for a process
+ *
+ * @device: Pointer to kgsl device struct
+ * @private: Pointer to the structure for the process
+ *
+ * @returns: 0 on success, error code otherwise
+ *
+ * kgsl_process_init_sysfs() is called at the time of creating the
+ * process struct when a process opens the kgsl device for the first time.
+ * This function creates the sysfs files for the process.
+ */
+int
+kgsl_process_init_sysfs(struct kgsl_device *device,
+		struct kgsl_process_private *private)
 {
 	unsigned char name[16];
-	int i, ret;
+	int i, ret = 0;
 
 	snprintf(name, sizeof(name), "%d", private->pid);
 
-	if (kobject_init_and_add(&private->kobj, &ktype_mem_entry,
-		kgsl_driver.prockobj, name))
-		return;
+	ret = kobject_init_and_add(&private->kobj, &ktype_mem_entry,
+		kgsl_driver.prockobj, name);
+
+	if (ret)
+		return ret;
 
 	for (i = 0; i < ARRAY_SIZE(mem_stats); i++) {
 		/* We need to check the value of sysfs_create_file, but we
@@ -191,6 +206,7 @@ kgsl_process_init_sysfs(struct kgsl_process_private *private)
 		ret = sysfs_create_file(&private->kobj,
 			&mem_stats[i].max_attr.attr);
 	}
+	return ret;
 }
 
 static int kgsl_drv_memstat_show(struct device *dev,

drivers/gpu/msm/kgsl_sharedmem.h

@@ -65,7 +65,8 @@ int kgsl_sharedmem_set(const struct kgsl_memdesc *memdesc,
 
 void kgsl_cache_range_op(struct kgsl_memdesc *memdesc, int op);
 
-void kgsl_process_init_sysfs(struct kgsl_process_private *private);
+int kgsl_process_init_sysfs(struct kgsl_device *device,
+		struct kgsl_process_private *private);
 void kgsl_process_uninit_sysfs(struct kgsl_process_private *private);
 
 int kgsl_sharedmem_init_sysfs(void);