Add some clarity to the printk subsystem by restructuring the code a bit. Move the kmsg variables and functions to a separate code file.
Signed-off-by: Joe Perches <[email protected]> --- kernel/printk/Makefile | 1 + kernel/printk/kmsg.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++ kernel/printk/printk.c | 107 --------------------------------------------- 3 files changed, 115 insertions(+), 107 deletions(-) create mode 100644 kernel/printk/kmsg.c diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile index 28b7129..396e085 100644 --- a/kernel/printk/Makefile +++ b/kernel/printk/Makefile @@ -1,3 +1,4 @@ obj-y += printk.o obj-y += log_buf.o obj-y += console.o +obj-y += kmsg.o diff --git a/kernel/printk/kmsg.c b/kernel/printk/kmsg.c new file mode 100644 index 0000000..ce64242 --- /dev/null +++ b/kernel/printk/kmsg.c @@ -0,0 +1,114 @@ +#include <linux/kernel.h> +#include <linux/nmi.h> +#include <linux/module.h> +#include <linux/kmsg_dump.h> + +#include "log_buf.h" + +static bool always_kmsg_dump; +module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); + +static DEFINE_SPINLOCK(dump_list_lock); +static LIST_HEAD(dump_list); + +/** + * kmsg_dump_register - register a kernel log dumper. + * @dumper: pointer to the kmsg_dumper structure + * + * Adds a kernel log dumper to the system. The dump callback in the + * structure will be called when the kernel oopses or panics and must be + * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. + */ +int kmsg_dump_register(struct kmsg_dumper *dumper) +{ + unsigned long flags; + int err = -EBUSY; + + /* The dump callback needs to be set */ + if (!dumper->dump) + return -EINVAL; + + spin_lock_irqsave(&dump_list_lock, flags); + /* Don't allow registering multiple times */ + if (!dumper->registered) { + dumper->registered = 1; + list_add_tail_rcu(&dumper->list, &dump_list); + err = 0; + } + spin_unlock_irqrestore(&dump_list_lock, flags); + + return err; +} +EXPORT_SYMBOL_GPL(kmsg_dump_register); + +/** + * kmsg_dump_unregister - unregister a kmsg dumper. + * @dumper: pointer to the kmsg_dumper structure + * + * Removes a dump device from the system. Returns zero on success and + * %-EINVAL otherwise. + */ +int kmsg_dump_unregister(struct kmsg_dumper *dumper) +{ + unsigned long flags; + int err = -EINVAL; + + spin_lock_irqsave(&dump_list_lock, flags); + if (dumper->registered) { + dumper->registered = 0; + list_del_rcu(&dumper->list); + err = 0; + } + spin_unlock_irqrestore(&dump_list_lock, flags); + synchronize_rcu(); + + return err; +} +EXPORT_SYMBOL_GPL(kmsg_dump_unregister); + +/** + * kmsg_dump - dump kernel log to kernel message dumpers. + * @reason: the reason (oops, panic etc) for dumping + * + * Iterate through each of the dump devices and call the oops/panic + * callbacks with the log buffer. + */ +void kmsg_dump(enum kmsg_dump_reason reason) +{ + unsigned long end; + unsigned chars; + struct kmsg_dumper *dumper; + const char *s1, *s2; + unsigned long l1, l2; + unsigned long flags; + + if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) + return; + + /* Theoretically, the log could move on after we do this, but + there's not a lot we can do about that. The new messages + will overwrite the start of what we dump. */ + raw_spin_lock_irqsave(&logbuf_lock, flags); + end = log_end & LOG_BUF_MASK; + chars = logged_chars; + raw_spin_unlock_irqrestore(&logbuf_lock, flags); + + if (chars > end) { + s1 = log_buf + log_buf_len - chars + end; + l1 = chars - end; + + s2 = log_buf; + l2 = end; + } else { + s1 = ""; + l1 = 0; + + s2 = log_buf + end - chars; + l2 = chars; + } + + rcu_read_lock(); + list_for_each_entry_rcu(dumper, &dump_list, list) + dumper->dump(dumper, reason, s1, l1, s2, l2); + rcu_read_unlock(); +} diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 3281441..aff4563 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -288,9 +288,6 @@ static bool printk_time = 0; #endif module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); -static bool always_kmsg_dump; -module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); - /** * printk - print a kernel message * @fmt: format string @@ -623,108 +620,4 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies, } EXPORT_SYMBOL(printk_timed_ratelimit); -static DEFINE_SPINLOCK(dump_list_lock); -static LIST_HEAD(dump_list); - -/** - * kmsg_dump_register - register a kernel log dumper. - * @dumper: pointer to the kmsg_dumper structure - * - * Adds a kernel log dumper to the system. The dump callback in the - * structure will be called when the kernel oopses or panics and must be - * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. - */ -int kmsg_dump_register(struct kmsg_dumper *dumper) -{ - unsigned long flags; - int err = -EBUSY; - - /* The dump callback needs to be set */ - if (!dumper->dump) - return -EINVAL; - - spin_lock_irqsave(&dump_list_lock, flags); - /* Don't allow registering multiple times */ - if (!dumper->registered) { - dumper->registered = 1; - list_add_tail_rcu(&dumper->list, &dump_list); - err = 0; - } - spin_unlock_irqrestore(&dump_list_lock, flags); - - return err; -} -EXPORT_SYMBOL_GPL(kmsg_dump_register); - -/** - * kmsg_dump_unregister - unregister a kmsg dumper. - * @dumper: pointer to the kmsg_dumper structure - * - * Removes a dump device from the system. Returns zero on success and - * %-EINVAL otherwise. - */ -int kmsg_dump_unregister(struct kmsg_dumper *dumper) -{ - unsigned long flags; - int err = -EINVAL; - - spin_lock_irqsave(&dump_list_lock, flags); - if (dumper->registered) { - dumper->registered = 0; - list_del_rcu(&dumper->list); - err = 0; - } - spin_unlock_irqrestore(&dump_list_lock, flags); - synchronize_rcu(); - - return err; -} -EXPORT_SYMBOL_GPL(kmsg_dump_unregister); - -/** - * kmsg_dump - dump kernel log to kernel message dumpers. - * @reason: the reason (oops, panic etc) for dumping - * - * Iterate through each of the dump devices and call the oops/panic - * callbacks with the log buffer. - */ -void kmsg_dump(enum kmsg_dump_reason reason) -{ - unsigned long end; - unsigned chars; - struct kmsg_dumper *dumper; - const char *s1, *s2; - unsigned long l1, l2; - unsigned long flags; - - if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) - return; - - /* Theoretically, the log could move on after we do this, but - there's not a lot we can do about that. The new messages - will overwrite the start of what we dump. */ - raw_spin_lock_irqsave(&logbuf_lock, flags); - end = log_end & LOG_BUF_MASK; - chars = logged_chars; - raw_spin_unlock_irqrestore(&logbuf_lock, flags); - - if (chars > end) { - s1 = log_buf + log_buf_len - chars + end; - l1 = chars - end; - - s2 = log_buf; - l2 = end; - } else { - s1 = ""; - l1 = 0; - - s2 = log_buf + end - chars; - l2 = chars; - } - - rcu_read_lock(); - list_for_each_entry_rcu(dumper, &dump_list, list) - dumper->dump(dumper, reason, s1, l1, s2, l2); - rcu_read_unlock(); -} #endif -- 1.7.8.111.gad25c.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
