diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 09:01:36 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 09:01:36 -0800 |
commit | 98d0052d0d9dcd5323833482712b5799ed0bbb0b (patch) | |
tree | e055e679d2aebf8b11d82b010775d96794295106 /drivers/net | |
parent | 73fa58dca80293320f5cfeb06f5b2daeb8d97bd5 (diff) | |
parent | 6b2b0d839acaa84f05a77184370f793752e786e9 (diff) |
Merge tag 'printk-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- Add NMI-safe SRCU reader API. It uses atomic_inc() instead of
this_cpu_inc() on strong load-store architectures.
- Introduce new console_list_lock to synchronize a manipulation of the
list of registered consoles and their flags.
This is a first step in removing the big-kernel-lock-like behavior of
console_lock(). This semaphore still serializes console->write()
calbacks against:
- each other. It primary prevents potential races between early
and proper console drivers using the same device.
- suspend()/resume() callbacks and init() operations in some
drivers.
- various other operations in the tty/vt and framebufer
susbsystems. It is likely that console_lock() serializes even
operations that are not directly conflicting with the
console->write() callbacks here. This is the most complicated
big-kernel-lock aspect of the console_lock() that will be hard
to untangle.
- Introduce new console_srcu lock that is used to safely iterate and
access the registered console drivers under SRCU read lock.
This is a prerequisite for introducing atomic console drivers and
console kthreads. It will reduce the complexity of serialization
against normal consoles and console_lock(). Also it should remove the
risk of deadlock during critical situations, like Oops or panic, when
only atomic consoles are registered.
- Check whether the console is registered instead of enabled on many
locations. It was a historical leftover.
- Cleanly force a preferred console in xenfb code instead of a dirty
hack.
- A lot of code and comment clean ups and improvements.
* tag 'printk-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (47 commits)
printk: htmldocs: add missing description
tty: serial: sh-sci: use setup() callback for early console
printk: relieve console_lock of list synchronization duties
tty: serial: kgdboc: use console_list_lock to trap exit
tty: serial: kgdboc: synchronize tty_find_polling_driver() and register_console()
tty: serial: kgdboc: use console_list_lock for list traversal
tty: serial: kgdboc: use srcu console list iterator
proc: consoles: use console_list_lock for list iteration
tty: tty_io: use console_list_lock for list synchronization
printk, xen: fbfront: create/use safe function for forcing preferred
netconsole: avoid CON_ENABLED misuse to track registration
usb: early: xhci-dbc: use console_is_registered()
tty: serial: xilinx_uartps: use console_is_registered()
tty: serial: samsung_tty: use console_is_registered()
tty: serial: pic32_uart: use console_is_registered()
tty: serial: earlycon: use console_is_registered()
tty: hvc: use console_is_registered()
efi: earlycon: use console_is_registered()
tty: nfcon: use console_is_registered()
serial_core: replace uart_console_enabled() with uart_console_registered()
...
Diffstat (limited to 'drivers/net')
-rw-r--r-- | drivers/net/netconsole.c | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index bdff9ac5056d..4f4f79532c6c 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -332,10 +332,8 @@ static ssize_t enabled_store(struct config_item *item, } if (enabled) { /* true */ - if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) { - netconsole_ext.flags |= CON_ENABLED; + if (nt->extended && !console_is_registered(&netconsole_ext)) register_console(&netconsole_ext); - } /* * Skip netpoll_parse_options() -- all the attributes are @@ -869,7 +867,7 @@ static void write_msg(struct console *con, const char *msg, unsigned int len) static struct console netconsole_ext = { .name = "netcon_ext", - .flags = CON_EXTENDED, /* starts disabled, registered on first use */ + .flags = CON_ENABLED | CON_EXTENDED, .write = write_ext_msg, }; @@ -883,6 +881,7 @@ static int __init init_netconsole(void) { int err; struct netconsole_target *nt, *tmp; + bool extended = false; unsigned long flags; char *target_config; char *input = config; @@ -895,11 +894,12 @@ static int __init init_netconsole(void) goto fail; } /* Dump existing printks when we register */ - if (nt->extended) - netconsole_ext.flags |= CON_PRINTBUFFER | - CON_ENABLED; - else + if (nt->extended) { + extended = true; + netconsole_ext.flags |= CON_PRINTBUFFER; + } else { netconsole.flags |= CON_PRINTBUFFER; + } spin_lock_irqsave(&target_list_lock, flags); list_add(&nt->list, &target_list); @@ -915,7 +915,7 @@ static int __init init_netconsole(void) if (err) goto undonotifier; - if (netconsole_ext.flags & CON_ENABLED) + if (extended) register_console(&netconsole_ext); register_console(&netconsole); pr_info("network logging started\n"); @@ -945,7 +945,8 @@ static void __exit cleanup_netconsole(void) { struct netconsole_target *nt, *tmp; - unregister_console(&netconsole_ext); + if (console_is_registered(&netconsole_ext)) + unregister_console(&netconsole_ext); unregister_console(&netconsole); dynamic_netconsole_exit(); unregister_netdevice_notifier(&netconsole_netdev_notifier); |