diff options
| author | John Ogness <john.ogness@linutronix.de> | 2024-09-04 14:11:24 +0206 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2024-09-04 15:56:32 +0200 |
| commit | fb9fabf3d86216961d1103ecbc33e98d5f6c48f5 (patch) | |
| tree | 055350c243e9ec4761c8171fbcd50e7353b2fddc /kernel/printk | |
| parent | 6cb58cfebb293286f5ce8f6fba3e29122308e9e0 (diff) | |
printk: nbcon: Init @nbcon_seq to highest possible
When initializing an nbcon console, have nbcon_alloc() set
@nbcon_seq to the highest possible sequence number. For all
practical purposes, this will guarantee that the console
will have nothing to print until later when @nbcon_seq is
set to the proper initial printing value.
This will be particularly important once kthread printing is
introduced because nbcon_alloc() can create/start the kthread
before the desired initial sequence number is known.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240904120536.115780-6-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/nbcon.c | 8 | ||||
| -rw-r--r-- | kernel/printk/printk_ringbuffer.h | 2 |
2 files changed, 9 insertions, 1 deletions
diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c index 88db24f9a8de..bc684ff5028a 100644 --- a/kernel/printk/nbcon.c +++ b/kernel/printk/nbcon.c @@ -1397,7 +1397,13 @@ bool nbcon_alloc(struct console *con) struct nbcon_state state = { }; nbcon_state_set(con, &state); - atomic_long_set(&ACCESS_PRIVATE(con, nbcon_seq), 0); + + /* + * Initialize @nbcon_seq to the highest possible sequence number so + * that practically speaking it will have nothing to print until a + * desired initial sequence number has been set via nbcon_seq_force(). + */ + atomic_long_set(&ACCESS_PRIVATE(con, nbcon_seq), ULSEQ_MAX(prb)); if (con->flags & CON_BOOT) { /* diff --git a/kernel/printk/printk_ringbuffer.h b/kernel/printk/printk_ringbuffer.h index 8de6c495cf2b..4ef81349d9fb 100644 --- a/kernel/printk/printk_ringbuffer.h +++ b/kernel/printk/printk_ringbuffer.h @@ -404,10 +404,12 @@ u64 prb_next_reserve_seq(struct printk_ringbuffer *rb); #define __u64seq_to_ulseq(u64seq) (u64seq) #define __ulseq_to_u64seq(rb, ulseq) (ulseq) +#define ULSEQ_MAX(rb) (-1) #else /* CONFIG_64BIT */ #define __u64seq_to_ulseq(u64seq) ((u32)u64seq) +#define ULSEQ_MAX(rb) __u64seq_to_ulseq(prb_first_seq(rb) + 0x80000000UL) static inline u64 __ulseq_to_u64seq(struct printk_ringbuffer *rb, u32 ulseq) { |