Merge tag 'trace-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Remove eventfs_file descriptor

   This is the biggest change, and the second part of making eventfs
   create its files dynamically.

   In 6.6 the first part was added, and that maintained a one to one
   mapping between eventfs meta descriptors and the directories and file
   inodes and dentries that were dynamically created. The directories
   were represented by a eventfs_inode and the files were represented by
   a eventfs_file.

   In v6.7 the eventfs_file is removed. As all events have the same
   directory make up (sched_switch has an "enable", "id", "format", etc
   files), the handing of what files are underneath each leaf eventfs
   directory is moved back to the tracing subsystem via a callback.

   When an event is added to the eventfs, it registers an array of
   evenfs_entry's. These hold the names of the files and the callbacks
   to call when the file is referenced. The callback gets the name so
   that the same callback may be used by multiple files. The callback
   then supplies the filesystem_operations structure needed to create
   this file.

   This has brought the memory footprint of creating multiple eventfs
   instances down by 2 megs each!

 - User events now has persistent events that are not associated to a
   single processes. These are privileged events that hang around even
   if no process is attached to them

 - Clean up of seq_buf

   There's talk about using seq_buf more to replace strscpy() and
   friends. But this also requires some minor modifications of seq_buf
   to be able to do this

 - Expand instance ring buffers individually

   Currently if boot up creates an instance, and a trace event is
   enabled on that instance, the ring buffer for that instance and the
   top level ring buffer are expanded (1.4 MB per CPU). This wastes
   memory as this happens when nothing is using the top level instance

 - Other minor clean ups and fixes

* tag 'trace-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (34 commits)
  seq_buf: Export seq_buf_puts()
  seq_buf: Export seq_buf_putc()
  eventfs: Use simple_recursive_removal() to clean up dentries
  eventfs: Remove special processing of dput() of events directory
  eventfs: Delete eventfs_inode when the last dentry is freed
  eventfs: Hold eventfs_mutex when calling callback functions
  eventfs: Save ownership and mode
  eventfs: Test for ei->is_freed when accessing ei->dentry
  eventfs: Have a free_ei() that just frees the eventfs_inode
  eventfs: Remove "is_freed" union with rcu head
  eventfs: Fix kerneldoc of eventfs_remove_rec()
  tracing: Have the user copy of synthetic event address use correct context
  eventfs: Remove extra dget() in eventfs_create_events_dir()
  tracing: Have trace_event_file have ref counters
  seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()
  eventfs: Fix typo in eventfs_inode union comment
  eventfs: Fix WARN_ON() in create_file_dentry()
  powerpc: Remove initialisation of readpos
  tracing/histograms: Simplify last_cmd_set()
  seq_buf: fix a misleading comment
  ...

4 files changed, 113 insertions, 4 deletions

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc
index 21db6b720754..e21c9c27ece4 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc
@@ -40,7 +40,9 @@ riscv*)
 esac
 
 : "Test get argument (1)"
-if grep -q eventfs_add_dir available_filter_functions; then
+if grep -q eventfs_create_dir available_filter_functions; then
+  DIR_NAME="eventfs_create_dir"
+elif grep -q eventfs_add_dir available_filter_functions; then
   DIR_NAME="eventfs_add_dir"
 else
   DIR_NAME="tracefs_create_dir"
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
index 4e086f871cee..93217d459556 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
@@ -40,7 +40,9 @@ riscv*)
 esac
 
 : "Test get argument (1)"
-if grep -q eventfs_add_dir available_filter_functions; then
+if grep -q eventfs_create_dir available_filter_functions; then
+  DIR_NAME="eventfs_create_dir"
+elif grep -q eventfs_add_dir available_filter_functions; then
   DIR_NAME="eventfs_add_dir"
 else
   DIR_NAME="tracefs_create_dir"
diff --git a/tools/testing/selftests/user_events/abi_test.c b/tools/testing/selftests/user_events/abi_test.c
index f5575ef2007c..cef1ff1af223 100644
--- a/tools/testing/selftests/user_events/abi_test.c
+++ b/tools/testing/selftests/user_events/abi_test.c
@@ -24,6 +24,18 @@
 const char *data_file = "/sys/kernel/tracing/user_events_data";
 const char *enable_file = "/sys/kernel/tracing/events/user_events/__abi_event/enable";
 
+static bool event_exists(void)
+{
+	int fd = open(enable_file, O_RDWR);
+
+	if (fd < 0)
+		return false;
+
+	close(fd);
+
+	return true;
+}
+
 static int change_event(bool enable)
 {
 	int fd = open(enable_file, O_RDWR);
@@ -47,7 +59,22 @@ static int change_event(bool enable)
 	return ret;
 }
 
-static int reg_enable(void *enable, int size, int bit)
+static int event_delete(void)
+{
+	int fd = open(data_file, O_RDWR);
+	int ret;
+
+	if (fd < 0)
+		return -1;
+
+	ret = ioctl(fd, DIAG_IOCSDEL, "__abi_event");
+
+	close(fd);
+
+	return ret;
+}
+
+static int reg_enable_flags(void *enable, int size, int bit, int flags)
 {
 	struct user_reg reg = {0};
 	int fd = open(data_file, O_RDWR);
@@ -58,6 +85,7 @@ static int reg_enable(void *enable, int size, int bit)
 
 	reg.size = sizeof(reg);
 	reg.name_args = (__u64)"__abi_event";
+	reg.flags = flags;
 	reg.enable_bit = bit;
 	reg.enable_addr = (__u64)enable;
 	reg.enable_size = size;
@@ -69,6 +97,11 @@ static int reg_enable(void *enable, int size, int bit)
 	return ret;
 }
 
+static int reg_enable(void *enable, int size, int bit)
+{
+	return reg_enable_flags(enable, size, bit, 0);
+}
+
 static int reg_disable(void *enable, int bit)
 {
 	struct user_unreg reg = {0};
@@ -128,6 +161,26 @@ TEST_F(user, enablement) {
 	ASSERT_EQ(0, change_event(false));
 }
 
+TEST_F(user, flags) {
+	/* USER_EVENT_REG_PERSIST is allowed */
+	ASSERT_EQ(0, reg_enable_flags(&self->check, sizeof(int), 0,
+				      USER_EVENT_REG_PERSIST));
+	ASSERT_EQ(0, reg_disable(&self->check, 0));
+
+	/* Ensure it exists after close and disable */
+	ASSERT_TRUE(event_exists());
+
+	/* Ensure we can delete it */
+	ASSERT_EQ(0, event_delete());
+
+	/* USER_EVENT_REG_MAX or above is not allowed */
+	ASSERT_EQ(-1, reg_enable_flags(&self->check, sizeof(int), 0,
+				       USER_EVENT_REG_MAX));
+
+	/* Ensure it does not exist after invalid flags */
+	ASSERT_FALSE(event_exists());
+}
+
 TEST_F(user, bit_sizes) {
 	/* Allow 0-31 bits for 32-bit */
 	ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
diff --git a/tools/testing/selftests/user_events/dyn_test.c b/tools/testing/selftests/user_events/dyn_test.c
index a85980190bea..bdf9ab127488 100644
--- a/tools/testing/selftests/user_events/dyn_test.c
+++ b/tools/testing/selftests/user_events/dyn_test.c
@@ -17,9 +17,25 @@
 #include "../kselftest_harness.h"
 #include "user_events_selftests.h"
 
+const char *dyn_file = "/sys/kernel/tracing/dynamic_events";
 const char *abi_file = "/sys/kernel/tracing/user_events_data";
 const char *enable_file = "/sys/kernel/tracing/events/user_events/__test_event/enable";
 
+static int event_delete(void)
+{
+	int fd = open(abi_file, O_RDWR);
+	int ret;
+
+	if (fd < 0)
+		return -1;
+
+	ret = ioctl(fd, DIAG_IOCSDEL, "__test_event");
+
+	close(fd);
+
+	return ret;
+}
+
 static bool wait_for_delete(void)
 {
 	int i;
@@ -64,7 +80,31 @@ static int unreg_event(int fd, int *check, int bit)
 	return ioctl(fd, DIAG_IOCSUNREG, &unreg);
 }
 
-static int parse(int *check, const char *value)
+static int parse_dyn(const char *value)
+{
+	int fd = open(dyn_file, O_RDWR | O_APPEND);
+	int len = strlen(value);
+	int ret;
+
+	if (fd == -1)
+		return -1;
+
+	ret = write(fd, value, len);
+
+	if (ret == len)
+		ret = 0;
+	else
+		ret = -1;
+
+	close(fd);
+
+	if (ret == 0)
+		event_delete();
+
+	return ret;
+}
+
+static int parse_abi(int *check, const char *value)
 {
 	int fd = open(abi_file, O_RDWR);
 	int ret;
@@ -90,6 +130,18 @@ static int parse(int *check, const char *value)
 	return ret;
 }
 
+static int parse(int *check, const char *value)
+{
+	int abi_ret = parse_abi(check, value);
+	int dyn_ret = parse_dyn(value);
+
+	/* Ensure both ABI and DYN parse the same way */
+	if (dyn_ret != abi_ret)
+		return -1;
+
+	return dyn_ret;
+}
+
 static int check_match(int *check, const char *first, const char *second, bool *match)
 {
 	int fd = open(abi_file, O_RDWR);