diff options
| author | John Ogness <john.ogness@linutronix.de> | 2024-08-20 08:35:39 +0206 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2024-08-21 14:56:23 +0200 |
| commit | adf6f37d142e14896115929f3892bbc0a86e25bf (patch) | |
| tree | f9698bf96f2e0ae470cc8e822780517a6d9d08c9 /include/linux/console.h | |
| parent | dc219d8d858d95549543aa7a41b6e64a0da9e406 (diff) | |
nbcon: Add API to acquire context for non-printing operations
Provide functions nbcon_device_try_acquire() and
nbcon_device_release() which will try to acquire the nbcon
console ownership with NBCON_PRIO_NORMAL and mark it unsafe for
handover/takeover.
These functions are to be used together with the device-specific
locking when performing non-printing activities on the console
device. They will allow synchronization against the
atomic_write() callback which will be serialized, for higher
priority contexts, only by acquiring the console context
ownership.
Pitfalls:
The API requires to be called in a context with migration
disabled because it uses per-CPU variables internally.
The context is set unsafe for a takeover all the time. It
guarantees full serialization against any atomic_write() caller
except for the final flush in panic() which might try an unsafe
takeover.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240820063001.36405-14-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'include/linux/console.h')
| -rw-r--r-- | include/linux/console.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/console.h b/include/linux/console.h index aafe3121b74e..3706f944de46 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -322,6 +322,7 @@ struct nbcon_write_context { * * @nbcon_state: State for nbcon consoles * @nbcon_seq: Sequence number of the next record for nbcon to print + * @nbcon_device_ctxt: Context available for non-printing operations * @pbufs: Pointer to nbcon private buffer */ struct console { @@ -417,6 +418,7 @@ struct console { atomic_t __private nbcon_state; atomic_long_t __private nbcon_seq; + struct nbcon_context __private nbcon_device_ctxt; struct printk_buffers *pbufs; }; |