X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=0d232589a9233b3f170810baf22a6af599e1dd06;hb=dd5656e59ca7b25fb60a22f9079905ed0da5ed0c;hp=2251be80cd22644bc82773ffb1cd59c6661dbc7e;hpb=025510cd20f4c35c3958bea133d96c9bd7c6ef9e;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/printk.c b/kernel/printk.c index 2251be8..0d23258 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -11,7 +11,7 @@ * Ted Ts'o, 2/11/93. * Modified for sysctl support, 1/8/97, Chris Horn. * Fixed SMP synchronization, 08/08/99, Manfred Spraul - * manfreds@colorfullife.com + * manfred@colorfullife.com * Rewrote bits to get rid of console_lock * 01Mar01 Andrew Morton */ @@ -20,12 +20,13 @@ #include #include #include -#include #include #include +#include +#include #include +#include #include /* For in_interrupt() */ -#include #include #include #include @@ -34,6 +35,13 @@ #include +/* + * Architectures can override it: + */ +void __attribute__((weak)) early_printk(const char *fmt, ...) +{ +} + #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) /* printk's without a loglevel use this.. */ @@ -52,10 +60,8 @@ int console_printk[4] = { DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ }; -EXPORT_SYMBOL(console_printk); - /* - * Low lever drivers may need that to know if they can schedule in + * Low level drivers may need that to know if they can schedule in * their unblank() callback or not. So let's export it. */ int oops_in_progress; @@ -67,6 +73,7 @@ EXPORT_SYMBOL(oops_in_progress); * driver system. */ static DECLARE_MUTEX(console_sem); +static DECLARE_MUTEX(secondary_console_sem); struct console *console_drivers; /* * This is used for debugging the mess that is the VT code by @@ -76,7 +83,7 @@ struct console *console_drivers; * path in the console code where we end up in places I want * locked without the console sempahore held */ -static int console_locked; +static int console_locked, console_suspended; /* * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars @@ -85,16 +92,16 @@ static int console_locked; */ static DEFINE_SPINLOCK(logbuf_lock); -#define LOG_BUF_MASK (log_buf_len-1) +#define LOG_BUF_MASK (log_buf_len-1) #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK]) /* * The indices into log_buf are not constrained to log_buf_len - they * must be masked before subscripting */ -static unsigned long log_start; /* Index into log_buf: next char to be read by syslog() */ -static unsigned long con_start; /* Index into log_buf: next char to be sent to consoles */ -static unsigned long log_end; /* Index into log_buf: most-recently-written-char + 1 */ +static unsigned log_start; /* Index into log_buf: next char to be read by syslog() */ +static unsigned con_start; /* Index into log_buf: next char to be sent to consoles */ +static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */ /* * Array of consoles built from command line options (console=) @@ -120,55 +127,17 @@ static int console_may_schedule; static char __log_buf[__LOG_BUF_LEN]; static char *log_buf = __log_buf; static int log_buf_len = __LOG_BUF_LEN; -static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */ - -/* - * Setup a list of consoles. Called from init/main.c - */ -static int __init console_setup(char *str) -{ - char name[sizeof(console_cmdline[0].name)]; - char *s, *options; - int idx; - - /* - * Decode str into name, index, options. - */ - if (str[0] >= '0' && str[0] <= '9') { - strcpy(name, "ttyS"); - strncpy(name + 4, str, sizeof(name) - 5); - } else - strncpy(name, str, sizeof(name) - 1); - name[sizeof(name) - 1] = 0; - if ((options = strchr(str, ',')) != NULL) - *(options++) = 0; -#ifdef __sparc__ - if (!strcmp(str, "ttya")) - strcpy(name, "ttyS0"); - if (!strcmp(str, "ttyb")) - strcpy(name, "ttyS1"); -#endif - for (s = name; *s; s++) - if ((*s >= '0' && *s <= '9') || *s == ',') - break; - idx = simple_strtoul(s, NULL, 10); - *s = 0; - - add_preferred_console(name, idx, options); - return 1; -} - -__setup("console=", console_setup); +static unsigned logged_chars; /* Number of chars produced since last read+clear operation */ static int __init log_buf_len_setup(char *str) { - unsigned long size = memparse(str, &str); + unsigned size = memparse(str, &str); unsigned long flags; if (size) size = roundup_pow_of_two(size); if (size > log_buf_len) { - unsigned long start, dest_idx, offset; + unsigned start, dest_idx, offset; char *new_log_buf; new_log_buf = alloc_bootmem(size); @@ -201,6 +170,113 @@ out: __setup("log_buf_len=", log_buf_len_setup); +#ifdef CONFIG_BOOT_PRINTK_DELAY + +static unsigned int boot_delay; /* msecs delay after each printk during bootup */ +static unsigned long long printk_delay_msec; /* per msec, based on boot_delay */ + +static int __init boot_delay_setup(char *str) +{ + unsigned long lpj; + unsigned long long loops_per_msec; + + lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ + loops_per_msec = (unsigned long long)lpj / 1000 * HZ; + + get_option(&str, &boot_delay); + if (boot_delay > 10 * 1000) + boot_delay = 0; + + printk_delay_msec = loops_per_msec; + printk(KERN_DEBUG "boot_delay: %u, preset_lpj: %ld, lpj: %lu, " + "HZ: %d, printk_delay_msec: %llu\n", + boot_delay, preset_lpj, lpj, HZ, printk_delay_msec); + return 1; +} +__setup("boot_delay=", boot_delay_setup); + +static void boot_delay_msec(void) +{ + unsigned long long k; + unsigned long timeout; + + if (boot_delay == 0 || system_state != SYSTEM_BOOTING) + return; + + k = (unsigned long long)printk_delay_msec * boot_delay; + + timeout = jiffies + msecs_to_jiffies(boot_delay); + while (k) { + k--; + cpu_relax(); + /* + * use (volatile) jiffies to prevent + * compiler reduction; loop termination via jiffies + * is secondary and may or may not happen. + */ + if (time_after(jiffies, timeout)) + break; + touch_nmi_watchdog(); + } +} +#else +static inline void boot_delay_msec(void) +{ +} +#endif + +/* + * Return the number of unread characters in the log buffer. + */ +int log_buf_get_len(void) +{ + return logged_chars; +} + +/* + * Copy a range of characters from the log buffer. + */ +int log_buf_copy(char *dest, int idx, int len) +{ + int ret, max; + bool took_lock = false; + + if (!oops_in_progress) { + spin_lock_irq(&logbuf_lock); + took_lock = true; + } + + max = log_buf_get_len(); + if (idx < 0 || idx >= max) { + ret = -1; + } else { + if (len > max) + len = max; + ret = len; + idx += (log_end - max); + while (len-- > 0) + dest[len] = LOG_BUF(idx + len); + } + + if (took_lock) + spin_unlock_irq(&logbuf_lock); + + return ret; +} + +/* + * Extract a single character from the log buffer. + */ +int log_buf_read(int idx) +{ + char ret; + + if (log_buf_copy(&ret, idx, 1) == 1) + return ret; + else + return -1; +} + /* * Commands to do_syslog: * @@ -218,7 +294,7 @@ __setup("log_buf_len=", log_buf_len_setup); */ int do_syslog(int type, char __user *buf, int len) { - unsigned long i, j, limit, count; + unsigned i, j, limit, count; int do_clear = 0; char c; int error = 0; @@ -359,23 +435,37 @@ asmlinkage long sys_syslog(int type, char __user *buf, int len) /* * Call the console drivers on a range of log_buf */ -static void __call_console_drivers(unsigned long start, unsigned long end) +static void __call_console_drivers(unsigned start, unsigned end) { struct console *con; for (con = console_drivers; con; con = con->next) { - if ((con->flags & CON_ENABLED) && con->write) + if ((con->flags & CON_ENABLED) && con->write && + (cpu_online(smp_processor_id()) || + (con->flags & CON_ANYTIME))) con->write(con, &LOG_BUF(start), end - start); } } +static int __read_mostly ignore_loglevel; + +static int __init ignore_loglevel_setup(char *str) +{ + ignore_loglevel = 1; + printk(KERN_INFO "debug: ignoring loglevel setting.\n"); + + return 0; +} + +early_param("ignore_loglevel", ignore_loglevel_setup); + /* * Write out chars from start to end - 1 inclusive */ -static void _call_console_drivers(unsigned long start, - unsigned long end, int msg_log_level) +static void _call_console_drivers(unsigned start, + unsigned end, int msg_log_level) { - if (msg_log_level < console_loglevel && + if ((msg_log_level < console_loglevel || ignore_loglevel) && console_drivers && start != end) { if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) { /* wrapped write */ @@ -393,13 +483,12 @@ static void _call_console_drivers(unsigned long start, * log_buf[start] to log_buf[end - 1]. * The console_sem must be held. */ -static void call_console_drivers(unsigned long start, unsigned long end) +static void call_console_drivers(unsigned start, unsigned end) { - unsigned long cur_index, start_print; + unsigned cur_index, start_print; static int msg_level = -1; - if (((long)(start - end)) > 0) - BUG(); + BUG_ON(((int)(start - end)) > 0); cur_index = start; start_print = start; @@ -475,27 +564,28 @@ static int printk_time = 1; #else static int printk_time = 0; #endif +module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); -static int __init printk_time_setup(char *str) +/* Check if we have any console registered that can be called early in boot. */ +static int have_callable_console(void) { - if (*str) - return 0; - printk_time = 1; - return 1; -} + struct console *con; -__setup("time", printk_time_setup); + for (con = console_drivers; con; con = con->next) + if (con->flags & CON_ANYTIME) + return 1; -__attribute__((weak)) unsigned long long printk_clock(void) -{ - return sched_clock(); + return 0; } /** * printk - print a kernel message * @fmt: format string * - * This is printk. It can be called from any context. We want it to work. + * This is printk(). It can be called from any context. We want it to work. + * Be aware of the fact that if oops_in_progress is not set, we might try to + * wake klogd up which could deadlock on runqueue lock if printk() is called + * from scheduler code. * * We try to grab the console_sem. If we succeed, it's easy - we log the output and * call the console drivers. If we fail to get the semaphore we place the output @@ -526,26 +616,104 @@ asmlinkage int printk(const char *fmt, ...) /* cpu currently holding logbuf_lock */ static volatile unsigned int printk_cpu = UINT_MAX; +/* + * Can we actually use the console at this time on this cpu? + * + * Console drivers may assume that per-cpu resources have + * been allocated. So unless they're explicitly marked as + * being able to cope (CON_ANYTIME) don't call them until + * this CPU is officially up. + */ +static inline int can_use_console(unsigned int cpu) +{ + return cpu_online(cpu) || have_callable_console(); +} + +/* + * Try to get console ownership to actually show the kernel + * messages from a 'printk'. Return true (and with the + * console_semaphore held, and 'console_locked' set) if it + * is successful, false otherwise. + * + * This gets called with the 'logbuf_lock' spinlock held and + * interrupts disabled. It should return with 'lockbuf_lock' + * released but interrupts still disabled. + */ +static int acquire_console_semaphore_for_printk(unsigned int cpu) +{ + int retval = 0; + + if (!try_acquire_console_sem()) { + retval = 1; + + /* + * If we can't use the console, we need to release + * the console semaphore by hand to avoid flushing + * the buffer. We need to hold the console semaphore + * in order to do this test safely. + */ + if (!can_use_console(cpu)) { + console_locked = 0; + up(&console_sem); + retval = 0; + } + } + printk_cpu = UINT_MAX; + spin_unlock(&logbuf_lock); + return retval; +} + +const char printk_recursion_bug_msg [] = + KERN_CRIT "BUG: recent printk recursion!\n"; +static int printk_recursion_bug; + asmlinkage int vprintk(const char *fmt, va_list args) { + static int log_level_unknown = 1; + static char printk_buf[1024]; + unsigned long flags; - int printed_len; + int printed_len = 0; + int this_cpu; char *p; - static char printk_buf[1024]; - static int log_level_unknown = 1; + + boot_delay_msec(); preempt_disable(); - if (unlikely(oops_in_progress) && printk_cpu == smp_processor_id()) - /* If a crash is occurring during printk() on this CPU, - * make sure we can't deadlock */ + /* This stops the holder of console_sem just where we want him */ + raw_local_irq_save(flags); + this_cpu = smp_processor_id(); + + /* + * Ouch, printk recursed into itself! + */ + if (unlikely(printk_cpu == this_cpu)) { + /* + * If a crash is occurring during printk() on this CPU, + * then try to get the crash message out but make sure + * we can't deadlock. Otherwise just return to avoid the + * recursion and return - but flag the recursion so that + * it can be printed at the next appropriate moment: + */ + if (!oops_in_progress) { + printk_recursion_bug = 1; + goto out_restore_irqs; + } zap_locks(); + } - /* This stops the holder of console_sem just where we want him */ - spin_lock_irqsave(&logbuf_lock, flags); - printk_cpu = smp_processor_id(); + lockdep_off(); + spin_lock(&logbuf_lock); + printk_cpu = this_cpu; + if (printk_recursion_bug) { + printk_recursion_bug = 0; + strcpy(printk_buf, printk_recursion_bug_msg); + printed_len = sizeof(printk_recursion_bug_msg); + } /* Emit the output into the temporary buffer */ - printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args); + printed_len += vscnprintf(printk_buf + printed_len, + sizeof(printk_buf) - printed_len, fmt, args); /* * Copy the output into log_buf. If the caller didn't provide @@ -574,7 +742,7 @@ asmlinkage int vprintk(const char *fmt, va_list args) loglev_char = default_message_loglevel + '0'; } - t = printk_clock(); + t = cpu_clock(printk_cpu); nanosec_rem = do_div(t, 1000000000); tlen = sprintf(tbuf, "<%c>[%5lu.%06lu] ", @@ -604,37 +772,23 @@ asmlinkage int vprintk(const char *fmt, va_list args) log_level_unknown = 1; } - if (!cpu_online(smp_processor_id())) { - /* - * Some console drivers may assume that per-cpu resources have - * been allocated. So don't allow them to be called by this - * CPU until it is officially up. We shouldn't be calling into - * random console drivers on a CPU which doesn't exist yet.. - */ - printk_cpu = UINT_MAX; - spin_unlock_irqrestore(&logbuf_lock, flags); - goto out; - } - if (!down_trylock(&console_sem)) { - console_locked = 1; - /* - * We own the drivers. We can drop the spinlock and let - * release_console_sem() print the text - */ - printk_cpu = UINT_MAX; - spin_unlock_irqrestore(&logbuf_lock, flags); - console_may_schedule = 0; + /* + * Try to acquire and then immediately release the + * console semaphore. The release will do all the + * actual magic (print out buffers, wake up klogd, + * etc). + * + * The acquire_console_semaphore_for_printk() function + * will release 'logbuf_lock' regardless of whether it + * actually gets the semaphore or not. + */ + if (acquire_console_semaphore_for_printk(this_cpu)) release_console_sem(); - } else { - /* - * Someone else owns the drivers. We drop the spinlock, which - * allows the semaphore holder to proceed and to call the - * console drivers with the output which we just produced. - */ - printk_cpu = UINT_MAX; - spin_unlock_irqrestore(&logbuf_lock, flags); - } -out: + + lockdep_on(); +out_restore_irqs: + raw_local_irq_restore(flags); + preempt_enable(); return printed_len; } @@ -645,19 +799,52 @@ EXPORT_SYMBOL(vprintk); asmlinkage long sys_syslog(int type, char __user *buf, int len) { - return 0; + return -ENOSYS; } -int do_syslog(int type, char __user *buf, int len) +static void call_console_drivers(unsigned start, unsigned end) { - return 0; } -static void call_console_drivers(unsigned long start, unsigned long end) +#endif + +/* + * Set up a list of consoles. Called from init/main.c + */ +static int __init console_setup(char *str) { -} + char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ + char *s, *options; + int idx; + /* + * Decode str into name, index, options. + */ + if (str[0] >= '0' && str[0] <= '9') { + strcpy(buf, "ttyS"); + strncpy(buf + 4, str, sizeof(buf) - 5); + } else { + strncpy(buf, str, sizeof(buf) - 1); + } + buf[sizeof(buf) - 1] = 0; + if ((options = strchr(str, ',')) != NULL) + *(options++) = 0; +#ifdef __sparc__ + if (!strcmp(str, "ttya")) + strcpy(buf, "ttyS0"); + if (!strcmp(str, "ttyb")) + strcpy(buf, "ttyS1"); #endif + for (s = buf; *s; s++) + if ((*s >= '0' && *s <= '9') || *s == ',') + break; + idx = simple_strtoul(s, NULL, 10); + *s = 0; + + add_preferred_console(buf, idx, options); + return 1; +} +__setup("console=", console_setup); /** * add_preferred_console - add a device to the list of preferred consoles. @@ -672,7 +859,7 @@ static void call_console_drivers(unsigned long start, unsigned long end) * commonly to provide a default console (ie from PROM variables) when * the user has not supplied one. */ -int __init add_preferred_console(char *name, int idx, char *options) +int add_preferred_console(char *name, int idx, char *options) { struct console_cmdline *c; int i; @@ -681,7 +868,7 @@ int __init add_preferred_console(char *name, int idx, char *options) * See if this tty is not yet registered, and * if we have a slot free. */ - for(i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) + for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) if (strcmp(console_cmdline[i].name, name) == 0 && console_cmdline[i].index == idx) { selected_console = i; @@ -698,6 +885,57 @@ int __init add_preferred_console(char *name, int idx, char *options) return 0; } +int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) +{ + struct console_cmdline *c; + int i; + + for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) + if (strcmp(console_cmdline[i].name, name) == 0 && + console_cmdline[i].index == idx) { + c = &console_cmdline[i]; + memcpy(c->name, name_new, sizeof(c->name)); + c->name[sizeof(c->name) - 1] = 0; + c->options = options; + c->index = idx_new; + return i; + } + /* not found */ + return -1; +} + +int console_suspend_enabled = 1; +EXPORT_SYMBOL(console_suspend_enabled); + +static int __init console_suspend_disable(char *str) +{ + console_suspend_enabled = 0; + return 1; +} +__setup("no_console_suspend", console_suspend_disable); + +/** + * suspend_console - suspend the console subsystem + * + * This disables printk() while we go into suspend states + */ +void suspend_console(void) +{ + if (!console_suspend_enabled) + return; + printk("Suspending console(s)\n"); + acquire_console_sem(); + console_suspended = 1; +} + +void resume_console(void) +{ + if (!console_suspend_enabled) + return; + console_suspended = 0; + release_console_sem(); +} + /** * acquire_console_sem - lock the console system for exclusive use. * @@ -708,8 +946,11 @@ int __init add_preferred_console(char *name, int idx, char *options) */ void acquire_console_sem(void) { - if (in_interrupt()) - BUG(); + BUG_ON(in_interrupt()); + if (console_suspended) { + down(&secondary_console_sem); + return; + } down(&console_sem); console_locked = 1; console_may_schedule = 1; @@ -730,7 +971,12 @@ int is_console_locked(void) { return console_locked; } -EXPORT_SYMBOL(is_console_locked); + +void wake_up_klogd(void) +{ + if (!oops_in_progress && waitqueue_active(&log_wait)) + wake_up_interruptible(&log_wait); +} /** * release_console_sem - unlock the console system @@ -749,8 +995,15 @@ EXPORT_SYMBOL(is_console_locked); void release_console_sem(void) { unsigned long flags; - unsigned long _con_start, _log_end; - unsigned long wake_klogd = 0; + unsigned _con_start, _log_end; + unsigned wake_klogd = 0; + + if (console_suspended) { + up(&secondary_console_sem); + return; + } + + console_may_schedule = 0; for ( ; ; ) { spin_lock_irqsave(&logbuf_lock, flags); @@ -765,11 +1018,10 @@ void release_console_sem(void) local_irq_restore(flags); } console_locked = 0; - console_may_schedule = 0; up(&console_sem); spin_unlock_irqrestore(&logbuf_lock, flags); - if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait)) - wake_up_interruptible(&log_wait); + if (wake_klogd) + wake_up_klogd(); } EXPORT_SYMBOL(release_console_sem); @@ -868,10 +1120,21 @@ void register_console(struct console *console) { int i; unsigned long flags; + struct console *bootconsole = NULL; + + if (console_drivers) { + if (console->flags & CON_BOOT) + return; + if (console_drivers->flags & CON_BOOT) + bootconsole = console_drivers; + } - if (preferred_console < 0) + if (preferred_console < 0 || bootconsole || !console_drivers) preferred_console = selected_console; + if (console->early_setup) + console->early_setup(); + /* * See if we want to use this console driver. If we * didn't select a console we take the first one @@ -915,9 +1178,15 @@ void register_console(struct console *console) if (!(console->flags & CON_ENABLED)) return; - if (console_drivers && (console_drivers->flags & CON_BOOT)) { - unregister_console(console_drivers); + if (bootconsole && (console->flags & CON_CONSDEV)) { + printk(KERN_INFO "console handover: boot [%s%d] -> real [%s%d]\n", + bootconsole->name, bootconsole->index, + console->name, console->index); + unregister_console(bootconsole); console->flags &= ~CON_PRINTBUFFER; + } else { + printk(KERN_INFO "console [%s%d] enabled\n", + console->name, console->index); } /* @@ -967,16 +1236,11 @@ int unregister_console(struct console *console) } } - /* If last console is removed, we re-enable picking the first - * one that gets registered. Without that, pmac early boot console - * would prevent fbcon from taking over. - * + /* * If this isn't the last console and it has CON_CONSDEV set, we * need to set it on the next preferred console. */ - if (console_drivers == NULL) - preferred_console = selected_console; - else if (console->flags & CON_CONSDEV) + if (console_drivers != NULL && console->flags & CON_CONSDEV) console_drivers->flags |= CON_CONSDEV; release_console_sem(); @@ -984,6 +1248,19 @@ int unregister_console(struct console *console) } EXPORT_SYMBOL(unregister_console); +static int __init disable_boot_consoles(void) +{ + if (console_drivers != NULL) { + if (console_drivers->flags & CON_BOOT) { + printk(KERN_INFO "turn off boot console %s%d\n", + console_drivers->name, console_drivers->index); + return unregister_console(console_drivers); + } + } + return 0; +} +late_initcall(disable_boot_consoles); + /** * tty_write_message - write a message to a certain tty, not just the console. * @tty: the destination tty_struct @@ -995,11 +1272,12 @@ EXPORT_SYMBOL(unregister_console); */ void tty_write_message(struct tty_struct *tty, char *msg) { - if (tty && tty->driver->write) - tty->driver->write(tty, msg, strlen(msg)); + if (tty && tty->ops->write) + tty->ops->write(tty, msg, strlen(msg)); return; } +#if defined CONFIG_PRINTK /* * printk rate limiting, lifted from the networking subsystem. * @@ -1009,31 +1287,7 @@ void tty_write_message(struct tty_struct *tty, char *msg) */ int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst) { - static DEFINE_SPINLOCK(ratelimit_lock); - static unsigned long toks = 10 * 5 * HZ; - static unsigned long last_msg; - static int missed; - unsigned long flags; - unsigned long now = jiffies; - - spin_lock_irqsave(&ratelimit_lock, flags); - toks += now - last_msg; - last_msg = now; - if (toks > (ratelimit_burst * ratelimit_jiffies)) - toks = ratelimit_burst * ratelimit_jiffies; - if (toks >= ratelimit_jiffies) { - int lost = missed; - - missed = 0; - toks -= ratelimit_jiffies; - spin_unlock_irqrestore(&ratelimit_lock, flags); - if (lost) - printk(KERN_WARNING "printk: %d messages suppressed.\n", lost); - return 1; - } - missed++; - spin_unlock_irqrestore(&ratelimit_lock, flags); - return 0; + return __ratelimit(ratelimit_jiffies, ratelimit_burst); } EXPORT_SYMBOL(__printk_ratelimit); @@ -1049,3 +1303,24 @@ int printk_ratelimit(void) printk_ratelimit_burst); } EXPORT_SYMBOL(printk_ratelimit); + +/** + * printk_timed_ratelimit - caller-controlled printk ratelimiting + * @caller_jiffies: pointer to caller's state + * @interval_msecs: minimum interval between prints + * + * printk_timed_ratelimit() returns true if more than @interval_msecs + * milliseconds have elapsed since the last time printk_timed_ratelimit() + * returned true. + */ +bool printk_timed_ratelimit(unsigned long *caller_jiffies, + unsigned int interval_msecs) +{ + if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) { + *caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs); + return true; + } + return false; +} +EXPORT_SYMBOL(printk_timed_ratelimit); +#endif