[PATCH printk 0/3] Introduce sync mode

[John Ogness]

Hi,

As proposed in an LKML thread [0], here is a series to introduce a
new console feature to use synchronous printing. The feature is
activated using the keyword "sync" in the console= command line
argument. For example:

   console=ttyS0,115200,sync

Sync mode is only available for nbcon consoles that provide a
safe write_atomic() callback. Specifying it for other consoles
will have no effect other than a log entry that sync mode is not
supported.

Patch 3/3 shamelessly copied an implementation from Chris Down
to parse and update the console options. (Chris's version of 
find_and_remove_console_option() is here [1]). I slightly extended
the function to support valueless-options.

At some point we may want to add a sysfs interface to toggle sync
mode.

John Ogness

[0] https://lore.kernel.org/lkml/87v7aruub1.fsf@xxxxxxxxxxxxxxxxxxxxx
[1] https://lore.kernel.org/lkml/77aa59337507e067f3a4ad7e15375893612bcfa3.1763492585.git.chris@xxxxxxxxxxxxxx

John Ogness (3):
  printk: Introduce console sync mode
  proc: Add console sync support for /proc/consoles
  printk: Support setting console sync mode via console=

 Documentation/admin-guide/serial-console.rst |   8 ++
 fs/proc/consoles.c                           |   1 +
 include/linux/console.h                      |   2 +
 kernel/printk/console_cmdline.h              |   1 +
 kernel/printk/internal.h                     |   2 +
 kernel/printk/nbcon.c                        |  42 ++++++--
 kernel/printk/printk.c                       | 104 +++++++++++++++++++
 7 files changed, 154 insertions(+), 6 deletions(-)


base-commit: 080d60fffa8e0d285871cde8395438006a9b5b0c
-- 
2.47.3