[RFC PATCH v4 4/4] livepatch: Deprecate stack_order

stack_order is no longer needed for atomic-replace livepatches, as a
single function can only be modified by a unique replace_set.
Since this livepatch sysfs interface is mainly intended for kernel
developers, backward compatibility does not need to be maintained.

Signed-off-by: Yafang Shao <[email protected]>
Cc: Wardenjohn <[email protected]>
---
 .../ABI/removed/sysfs-kernel-livepatch        |  9 +++++++
 .../ABI/testing/sysfs-kernel-livepatch        |  9 -------
 kernel/livepatch/core.c                       | 24 -------------------
 3 files changed, 9 insertions(+), 33 deletions(-)

diff --git a/Documentation/ABI/removed/sysfs-kernel-livepatch b/Documentation/ABI/removed/sysfs-kernel-livepatch
index 87d57ba27326..fb6ff9c3b43e 100644
--- a/Documentation/ABI/removed/sysfs-kernel-livepatch
+++ b/Documentation/ABI/removed/sysfs-kernel-livepatch
@@ -5,3 +5,12 @@ Contact:	[email protected]
 Description:
 		An attribute which indicates whether the patch supports
 		atomic-replace.
+
+What:          /sys/kernel/livepatch/<patch>/stack_order
+Date:          Jan 2025
+KernelVersion: 6.14.0
+Description:
+		This attribute specifies the sequence in which live patch modules
+		are applied to the system. If multiple live patches modify the same
+		function, the implementation with the biggest 'stack_order' number
+		is used, unless a transition is currently in progress.
diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch
index 2588f676deb1..3564b3e4385f 100644
--- a/Documentation/ABI/testing/sysfs-kernel-livepatch
+++ b/Documentation/ABI/testing/sysfs-kernel-livepatch
@@ -67,15 +67,6 @@ Description:
 		either this patch's provides id or any id in the obsoletes
 		list will be atomically replaced.
 
-What:		/sys/kernel/livepatch/<patch>/stack_order
-Date:		Jan 2025
-KernelVersion:	6.14.0
-Description:
-		This attribute specifies the sequence in which live patch modules
-		are applied to the system. If multiple live patches modify the same
-		function, the implementation with the biggest 'stack_order' number
-		is used, unless a transition is currently in progress.
-
 What:		/sys/kernel/livepatch/<patch>/<object>
 Date:		Nov 2014
 KernelVersion:	3.19.0
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index bd37ed99814e..5cadced61d2d 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -352,7 +352,6 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
  * /sys/kernel/livepatch/<patch>/force
  * /sys/kernel/livepatch/<patch>/provides
  * /sys/kernel/livepatch/<patch>/obsoletes
- * /sys/kernel/livepatch/<patch>/stack_order
  * /sys/kernel/livepatch/<patch>/<object>
  * /sys/kernel/livepatch/<patch>/<object>/patched
  * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
@@ -477,40 +476,17 @@ static ssize_t obsoletes_show(struct kobject *kobj,
 	return len;
 }
 
-static ssize_t stack_order_show(struct kobject *kobj,
-				struct kobj_attribute *attr, char *buf)
-{
-	struct klp_patch *patch, *this_patch;
-	int stack_order = 0;
-
-	this_patch = container_of(kobj, struct klp_patch, kobj);
-
-	mutex_lock(&klp_mutex);
-
-	klp_for_each_patch(patch) {
-		stack_order++;
-		if (patch == this_patch)
-			break;
-	}
-
-	mutex_unlock(&klp_mutex);
-
-	return sysfs_emit(buf, "%d\n", stack_order);
-}
-
 static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled);
 static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition);
 static struct kobj_attribute force_kobj_attr = __ATTR_WO(force);
 static struct kobj_attribute provides_kobj_attr = __ATTR_RO(provides);
 static struct kobj_attribute obsoletes_kobj_attr = __ATTR_RO(obsoletes);
-static struct kobj_attribute stack_order_kobj_attr = __ATTR_RO(stack_order);
 static struct attribute *klp_patch_attrs[] = {
 	&enabled_kobj_attr.attr,
 	&transition_kobj_attr.attr,
 	&force_kobj_attr.attr,
 	&provides_kobj_attr.attr,
 	&obsoletes_kobj_attr.attr,
-	&stack_order_kobj_attr.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(klp_patch);
-- 
2.52.0