diff options
| author | John Ogness <john.ogness@linutronix.de> | 2024-08-20 08:35:50 +0206 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2024-08-21 14:56:24 +0200 |
| commit | 8ba77712a7501ca941603d6d5ed650cd0d42cafb (patch) | |
| tree | 63a04026dcc0905f1ba7494ffcad606b95dd02f7 /kernel/printk | |
| parent | 70411bf8d22ab3d2f794f199d81d70b62d3a85fa (diff) | |
printk: nbcon: Flush new records on device_release()
There may be new records that were added while a driver was
holding the nbcon context for non-printing purposes. These
new records must be flushed by the nbcon_device_release()
context because no other context will do it.
If boot consoles are registered, the legacy loop is used
(either direct or per irq_work) to handle the flushing.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240820063001.36405-25-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/internal.h | 2 | ||||
| -rw-r--r-- | kernel/printk/nbcon.c | 20 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 2 |
3 files changed, 23 insertions, 1 deletions
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 84706c1c934b..7679e18f24b3 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -153,6 +153,8 @@ static inline bool console_is_usable(struct console *con, short flags) { return #endif /* CONFIG_PRINTK */ +extern bool have_boot_console; + extern struct printk_buffers printk_shared_pbufs; /** diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c index d09c084c9af4..269aeed18064 100644 --- a/kernel/printk/nbcon.c +++ b/kernel/printk/nbcon.c @@ -1326,10 +1326,30 @@ EXPORT_SYMBOL_GPL(nbcon_device_try_acquire); void nbcon_device_release(struct console *con) { struct nbcon_context *ctxt = &ACCESS_PRIVATE(con, nbcon_device_ctxt); + int cookie; if (!nbcon_context_exit_unsafe(ctxt)) return; nbcon_context_release(ctxt); + + /* + * This context must flush any new records added while the console + * was locked. The console_srcu_read_lock must be taken to ensure + * the console is usable throughout flushing. + */ + cookie = console_srcu_read_lock(); + if (console_is_usable(con, console_srcu_read_flags(con)) && + prb_read_valid(prb, nbcon_seq_read(con), NULL)) { + if (!have_boot_console) { + __nbcon_atomic_flush_pending_con(con, prb_next_reserve_seq(prb)); + } else if (!is_printk_legacy_deferred()) { + if (console_trylock()) + console_unlock(); + } else { + printk_trigger_flush(); + } + } + console_srcu_read_unlock(cookie); } EXPORT_SYMBOL_GPL(nbcon_device_release); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f08bf5e82fc7..7c9f8f6e1738 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -469,7 +469,7 @@ static DEFINE_MUTEX(syslog_lock); * the console lock. This is because boot consoles and nbcon consoles may * have mapped the same hardware. */ -static bool have_boot_console; +bool have_boot_console; #ifdef CONFIG_PRINTK DECLARE_WAIT_QUEUE_HEAD(log_wait); |