tracing/user_events: Store register flags on events

Currently we don't have any available flags for user processes to use to
indicate options for user_events. We will soon have a flag to indicate
the event should or should not auto-delete once it's not being used by
anyone.

Add a reg_flags field to user_events and parameters to existing
functions to allow for this in future patches.

Link: https://lkml.kernel.org/r/20230614163336.5797-2-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index cf6d4c02c363c85db6fd21702e36cea21a19962b..629823e21447bfac2dc7558d3e967fa702e8bf9a 100644 (file)
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -87,6 +87,7 @@ struct user_event {
        struct list_head                validators;
        refcount_t                      refcnt;
        int                             min_size;
+       int                             reg_flags;
        char                            status;
 };
 
@@ -165,7 +166,7 @@ typedef void (*user_event_func_t) (struct user_event *user, struct iov_iter *i,
 
 static int user_event_parse(struct user_event_group *group, char *name,
                            char *args, char *flags,
-                           struct user_event **newuser);
+                           struct user_event **newuser, int reg_flags);
 
 static struct user_event_mm *user_event_mm_get(struct user_event_mm *mm);
 static struct user_event_mm *user_event_mm_get_all(struct user_event *user);
@@ -810,7 +811,8 @@ static struct list_head *user_event_get_fields(struct trace_event_call *call)
  * Upon success user_event has its ref count increased by 1.
  */
 static int user_event_parse_cmd(struct user_event_group *group,
-                               char *raw_command, struct user_event **newuser)
+                               char *raw_command, struct user_event **newuser,
+                               int reg_flags)
 {
        char *name = raw_command;
        char *args = strpbrk(name, " ");
@@ -824,7 +826,7 @@ static int user_event_parse_cmd(struct user_event_group *group,
        if (flags)
                *flags++ = '\0';
 
-       return user_event_parse(group, name, args, flags, newuser);
+       return user_event_parse(group, name, args, flags, newuser, reg_flags);
 }
 
 static int user_field_array_size(const char *type)
@@ -1588,7 +1590,7 @@ static int user_event_create(const char *raw_command)
 
        mutex_lock(&group->reg_mutex);
 
-       ret = user_event_parse_cmd(group, name, &user);
+       ret = user_event_parse_cmd(group, name, &user, 0);
 
        if (!ret)
                refcount_dec(&user->refcnt);
@@ -1751,7 +1753,7 @@ static int user_event_trace_register(struct user_event *user)
  */
 static int user_event_parse(struct user_event_group *group, char *name,
                            char *args, char *flags,
-                           struct user_event **newuser)
+                           struct user_event **newuser, int reg_flags)
 {
        int ret;
        u32 key;
@@ -1846,6 +1848,8 @@ error:
        if (ret)
                goto put_user_lock;
 
+       user->reg_flags = reg_flags;
+
        /* Ensure we track self ref and caller ref (2) */
        refcount_set(&user->refcnt, 2);
 
@@ -2144,7 +2148,7 @@ static long user_events_ioctl_reg(struct user_event_file_info *info,
                return ret;
        }
 
-       ret = user_event_parse_cmd(info->group, name, &user);
+       ret = user_event_parse_cmd(info->group, name, &user, reg.flags);
 
        if (ret) {
                kfree(name);