Re: [PATCH v3 4/4] tracing: move tracing declarations from kernel.h to a dedicated header
From: Yury Norov <yury.norov@gmail.com>
Date: 2025-12-18 20:33:48
Also in:
dri-devel, intel-gfx, linux-modules, lkml
On Thu, Dec 18, 2025 at 12:43:26PM -0500, Steven Rostedt wrote:
On Thu, 18 Dec 2025 12:33:49 -0500 Steven Rostedt [off-list ref] wrote:quoted
On Wed, 17 Dec 2025 22:59:33 -0500 Yury Norov [off-list ref] wrote:quoted
I deem to drop trace_printk.h from kernel.h - it is more aligned with the idea of unloading the header. The original motivation to keep trace_printk.h in kernel.h was just because a similar printk.h is living there. But after all, this is a purely debugging header, so no need for almost every C file to bear debugging stuff.It is a big deal for debugging stuff. A lot of developers debug their code with trace_printk(), and do the "shotgun approach", where they cut and paste trace_printk()s all over their code in several files. Having to now add: #include <linux/trace_printk.h> whenever a trace_printk() is added is going to be a big PITA and slow down all debugging efforts.I don't actually remember why I had __trace_puts() pass in the size. I could change it to:
This is the best approach. I'll schedule it for v4. Would you like me to take it as-is, or you'd send a patch?
quoted hunk ↗ jump to hunk
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 5b46924fdff5..d5a939b8c391 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h@@ -331,10 +331,10 @@ int __trace_printk(unsigned long ip, const char *fmt, ...); if (__builtin_constant_p(str)) \ __trace_bputs(_THIS_IP_, trace_printk_fmt); \ else \ - __trace_puts(_THIS_IP_, str, strlen(str)); \ + __trace_puts(_THIS_IP_, str); \ }) extern int __trace_bputs(unsigned long ip, const char *str); -extern int __trace_puts(unsigned long ip, const char *str, int size); +extern int __trace_puts(unsigned long ip, const char *str); extern void trace_dump_stack(int skip);diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e575956ef9b5..686741edb803 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c@@ -1178,11 +1178,10 @@ EXPORT_SYMBOL_GPL(__trace_array_puts); * __trace_puts - write a constant string into the trace buffer. * @ip: The address of the caller * @str: The constant string to write - * @size: The size of the string. */ -int __trace_puts(unsigned long ip, const char *str, int size) +int __trace_puts(unsigned long ip, const char *str) { - return __trace_array_puts(printk_trace, ip, str, size); + return __trace_array_puts(printk_trace, ip, str, strlen(str)); } EXPORT_SYMBOL_GPL(__trace_puts);@@ -1201,7 +1200,7 @@ int __trace_bputs(unsigned long ip, const char *str) int size = sizeof(struct bputs_entry); if (!printk_binsafe(tr)) - return __trace_puts(ip, str, strlen(str)); + return __trace_puts(ip, str); if (!(tr->trace_flags & TRACE_ITER(PRINTK))) return 0;diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index b6d42fe06115..de4e6713b84e 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h@@ -2116,7 +2116,7 @@ extern void tracing_log_err(struct trace_array *tr, * about performance). The internal_trace_puts() is for such * a purpose. */ -#define internal_trace_puts(str) __trace_puts(_THIS_IP_, str, strlen(str)) +#define internal_trace_puts(str) __trace_puts(_THIS_IP_, str) #undef FTRACE_ENTRY #define FTRACE_ENTRY(call, struct_name, id, tstruct, print) \Which removes the strlen() altogether. -- Steve