FAILED: patch "[PATCH] nvmem: core: fix registration vs use race" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

ab3428cfd9aa ("nvmem: core: fix registration vs use race")
560181d3ace6 ("nvmem: core: fix cleanup after dev_set_name()") 569653f022a2 ("nvmem: core: remove nvmem_config wp_gpio")
3bd747c7ea13 ("nvmem: core: initialise nvmem->id early")
5544e90c8126 ("nvmem: core: add error handling for dev_set_name") bd1244561fa2 ("nvmem: core: Fix memleak in nvmem_register()") f6c052afe6f8 ("nvmem: core: Fix a conflict between MTD and NVMEM on wp-gpios property") de0534df9347 ("nvmem: core: fix error handling while validating keepout regions") 1333a6779501 ("nvmem: core: allow specifying of_node")
fd3bb8f54a88 ("nvmem: core: Add support for keepout regions")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ab3428cfd9aa2f3463ee4b2909b5bb2193bd0c4a Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <[email protected]>
Date: Fri, 27 Jan 2023 10:40:11 +0000
Subject: [PATCH] nvmem: core: fix registration vs use race

The i.MX6 CPU frequency driver sometimes fails to register at boot time due to nvmem_cell_read_u32() sporadically returning -ENOENT.

This happens because there is a window where __nvmem_device_get() in of_nvmem_cell_get() is able to return the nvmem device, but as cells have been setup, nvmem_find_cell_entry_by_node() returns NULL.

The occurs because the nvmem core registration code violates one of the fundamental principles of kernel programming: do not publish data structures before their setup is complete.

Fix this by making nvmem core code conform with this principle.

index ac77a019aed7..e92c6f1aadbb 100644
@@ -832,22 +832,16 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 	nvmem->dev.groups = nvmem_dev_groups;
 #endif
 
-	dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
-
-	rval = device_add(&nvmem->dev);
-	if (rval)
-		goto err_put_device;
-
 	if (nvmem->nkeepout) {
 		rval = nvmem_validate_keepouts(nvmem);
 		if (rval)
-			goto err_device_del;
+			goto err_put_device;
 	}
 
 	if (config->compat) {
 		rval = nvmem_sysfs_setup_compat(nvmem, config);
 		if (rval)
-			goto err_device_del;
+			goto err_put_device;
 	}
 
 	if (config->cells) {

@@ -864,6 +858,12 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 	if (rval)
 		goto err_remove_cells;
 
+	dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
+
+	rval = device_add(&nvmem->dev);
+	if (rval)
+		goto err_remove_cells;
+
 	blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
 
 	return nvmem;

@@ -873,8 +873,6 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 err_teardown_compat:
 	if (config->compat)
 		nvmem_sysfs_remove_compat(nvmem, config);
-err_device_del:
-	device_del(&nvmem->dev);
 err_put_device:
 	put_device(&nvmem->dev);