diff mbox series

[RFC,bpf-next,06/16] ftrace: Add unregister_ftrace_direct_ips function

Message ID 20201022082138.2322434-7-jolsa@kernel.org
State Not Applicable
Delegated to: BPF Maintainers
Headers show
Series bpf: Speed up trampoline attach | expand

Checks

Context Check Description
jkicinski/stable success Stable not CCed
jkicinski/header_inline success Link
jkicinski/build_allmodconfig_warn success Errors and warnings before: 2626 this patch: 2626
jkicinski/checkpatch success total: 0 errors, 0 warnings, 0 checks, 65 lines checked
jkicinski/verify_fixes success Link
jkicinski/kdoc success Errors and warnings before: 21 this patch: 21
jkicinski/build_32bit success Errors and warnings before: 2761 this patch: 2761
jkicinski/module_param success Was 0 now: 0
jkicinski/verify_signedoff success Link
jkicinski/source_inline success Was 0 now: 0
jkicinski/subject_prefix success Link
jkicinski/tree_selection success Clearly marked for bpf-next
jkicinski/patch_count fail Series longer than 15 patches
jkicinski/fixes_present success Link
jkicinski/cover_letter success Link

Commit Message

Jiri Olsa Oct. 22, 2020, 8:21 a.m. UTC
Adding unregister_ftrace_direct_ips function that allows
to unregister array of ip addresses and trampolines for
direct filter. the interface is:

  int unregister_ftrace_direct_ips(unsigned long *ips,
                                   unsigned long *addrs,
                                   int count);

It wil be used in following patches to unregister bpf
trampolines in batch mode.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/ftrace.h |  2 ++
 kernel/trace/ftrace.c  | 51 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)
diff mbox series

Patch

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 9ed52755667a..24525473043e 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -293,6 +293,8 @@  int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
 unsigned long ftrace_find_rec_direct(unsigned long ip);
 int register_ftrace_direct_ips(unsigned long *ips, unsigned long *addrs,
 			       int count);
+int unregister_ftrace_direct_ips(unsigned long *ips, unsigned long *addrs,
+				 int count);
 #else
 # define ftrace_direct_func_count 0
 static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 770bcd1a245a..15a13e6c1f31 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5374,6 +5374,57 @@  int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
 }
 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
 
+int unregister_ftrace_direct_ips(unsigned long *ips, unsigned long *addrs,
+				 int count)
+{
+	struct ftrace_direct_func *direct;
+	struct ftrace_func_entry *entry;
+	int i, del = 0, ret = -ENODEV;
+
+	mutex_lock(&direct_mutex);
+
+	for (i = 0; i < count; i++) {
+		entry = find_direct_entry(&ips[i], NULL);
+		if (!entry)
+			goto out_unlock;
+		del++;
+	}
+
+	if (direct_functions->count - del == 0)
+		unregister_ftrace_function(&direct_ops);
+
+	ret = ftrace_set_filter_ips(&direct_ops, ips, count, 1);
+
+	WARN_ON(ret);
+
+	for (i = 0; i < count; i++) {
+		entry = __ftrace_lookup_ip(direct_functions, ips[i]);
+		if (WARN_ON(!entry))
+			continue;
+
+		remove_hash_entry(direct_functions, entry);
+
+		direct = ftrace_find_direct_func(addrs[i]);
+		if (!WARN_ON(!direct)) {
+			/* This is the good path (see the ! before WARN) */
+			direct->count--;
+			WARN_ON(direct->count < 0);
+			if (!direct->count) {
+				list_del_rcu(&direct->next);
+				synchronize_rcu_tasks();
+				kfree(direct);
+				kfree(entry);
+				ftrace_direct_func_count--;
+			}
+		}
+	}
+ out_unlock:
+	mutex_unlock(&direct_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_ftrace_direct_ips);
+
 static struct ftrace_ops stub_ops = {
 	.func		= ftrace_stub,
 };