[PATCH printk v2 03/12] printk: get caller_id/timestamp after migration disable

John Ogness
2022-04-05T22:39:24Z

Currently the local CPU timestamp and caller_id for the record are
collected while migration is enabled. Since this information is
CPU-specific, it should be collected with migration disabled.

Migration is disabled immediately after collecting this information
anyway, so just move the information collection to after the
migration disabling.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
---
kernel/printk/printk.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 13a1eebe72af..9774a3f6bafb 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2041,7 +2041,7 @@ static inline void printk_delay(void)
static inline u32 printk_caller_id(void)
{
return in_task() ? task_pid_nr(current) :
- 0x80000000 + raw_smp_processor_id();
+ 0x80000000 + smp_processor_id();
}

/**
@@ -2123,7 +2123,6 @@ int vprintk_store(int facility, int level,
const struct dev_printk_info *dev_info,
const char *fmt, va_list args)
{
- const u32 caller_id = printk_caller_id();
struct prb_reserved_entry e;
enum printk_info_flags flags = 0;
struct printk_record r;
@@ -2133,10 +2132,14 @@ int vprintk_store(int facility, int level,
u8 *recursion_ptr;
u16 reserve_size;
va_list args2;
+ u32 caller_id;
u16 text_len;
int ret = 0;
u64 ts_nsec;

+ if (!printk_enter_irqsave(recursion_ptr, irqflags))
+ return 0;
+
/*
* Since the duration of printk() can vary depending on the message
* and state of the ringbuffer, grab the timestamp now so that it is
@@ -2145,8 +2148,7 @@ int vprintk_store(int facility, int level,
*/
ts_nsec = local_clock();

- if (!printk_enter_irqsave(recursion_ptr, irqflags))
- return 0;
+ caller_id = printk_caller_id();

/*
* The sprintf needs to come first since the syslog prefix might be
--
2.30.2