[PATCH 3/3] sysrq: add commentary on why we use the console loglevel over using KERN_EMERG

Andy Whitcroft
2009-01-07T21:50:14Z

Add an explanitory comment as to why we modify the kernel console
loglevel rather than simply moving sysrq messages to KERN_EMERG level.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
---
drivers/char/sysrq.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index d41b9f6..33a9351 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -473,6 +473,12 @@ void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
unsigned long flags;

spin_lock_irqsave(&sysrq_key_table_lock, flags);
+ /*
+ * Raise the apparent loglevel to maximum so that the sysrq header
+ * is shown to provide the user with positive feedback. We do not
+ * simply emit this at KERN_EMERG as that would change message
+ * routing in the consumers of /proc/kmsg.
+ */
orig_log_level = console_loglevel;
console_loglevel = 7;
printk(KERN_INFO "SysRq : ");
--
1.6.0.4.911.gc990