Instead of buffering continuous line parts before storing the full line into the ringbuffer, store each part as its own record.
Signed-off-by: John Ogness <[email protected]> --- kernel/printk/printk.c | 114 ++++------------------------------------- 1 file changed, 11 insertions(+), 103 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index fec71229169e..c4274c867771 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -495,9 +495,14 @@ static void truncate_msg(u16 *text_len, u16 *trunc_msg_len) *trunc_msg_len = 0; } +static inline u32 printk_caller_id(void) +{ + return in_task() ? task_pid_nr(current) : + 0x80000000 + raw_smp_processor_id(); +} + /* insert record into the buffer, discard old ones, update heads */ -static int log_store(u32 caller_id, int facility, int level, - enum log_flags flags, u64 ts_nsec, +static int log_store(int facility, int level, enum log_flags flags, const char *dict, u16 dict_len, const char *text, u16 text_len) { @@ -525,11 +530,8 @@ static int log_store(u32 caller_id, int facility, int level, r.info->facility = facility; r.info->level = level & 7; r.info->flags = flags & 0x1f; - if (ts_nsec > 0) - r.info->ts_nsec = ts_nsec; - else - r.info->ts_nsec = local_clock(); - r.info->caller_id = caller_id; + r.info->ts_nsec = local_clock(); + r.info->caller_id = printk_caller_id(); /* insert message */ prb_commit(&e); @@ -1874,100 +1876,6 @@ static inline void printk_delay(void) } } -static inline u32 printk_caller_id(void) -{ - return in_task() ? task_pid_nr(current) : - 0x80000000 + raw_smp_processor_id(); -} - -/* - * Continuation lines are buffered, and not committed to the record buffer - * until the line is complete, or a race forces it. The line fragments - * though, are printed immediately to the consoles to ensure everything has - * reached the console in case of a kernel crash. - */ -static struct cont { - char buf[LOG_LINE_MAX]; - size_t len; /* length == 0 means unused buffer */ - u32 caller_id; /* printk_caller_id() of first print */ - u64 ts_nsec; /* time of first print */ - u8 level; /* log level of first message */ - u8 facility; /* log facility of first message */ - enum log_flags flags; /* prefix, newline flags */ -} cont; - -static void cont_flush(void) -{ - if (cont.len == 0) - return; - - log_store(cont.caller_id, cont.facility, cont.level, cont.flags, - cont.ts_nsec, NULL, 0, cont.buf, cont.len); - cont.len = 0; -} - -static bool cont_add(u32 caller_id, int facility, int level, - enum log_flags flags, const char *text, size_t len) -{ - /* If the line gets too long, split it up in separate records. */ - if (cont.len + len > sizeof(cont.buf)) { - cont_flush(); - return false; - } - - if (!cont.len) { - cont.facility = facility; - cont.level = level; - cont.caller_id = caller_id; - cont.ts_nsec = local_clock(); - cont.flags = flags; - } - - memcpy(cont.buf + cont.len, text, len); - cont.len += len; - - // The original flags come from the first line, - // but later continuations can add a newline. - if (flags & LOG_NEWLINE) { - cont.flags |= LOG_NEWLINE; - cont_flush(); - } - - return true; -} - -static size_t log_output(int facility, int level, enum log_flags lflags, const char *dict, size_t dictlen, char *text, size_t text_len) -{ - const u32 caller_id = printk_caller_id(); - - /* - * If an earlier line was buffered, and we're a continuation - * write from the same context, try to add it to the buffer. - */ - if (cont.len) { - if (cont.caller_id == caller_id && (lflags & LOG_CONT)) { - if (cont_add(caller_id, facility, level, lflags, text, text_len)) - return text_len; - } - /* Otherwise, make sure it's flushed */ - cont_flush(); - } - - /* Skip empty continuation lines that couldn't be added - they just flush */ - if (!text_len && (lflags & LOG_CONT)) - return 0; - - /* If it doesn't end in a newline, try to buffer the current line */ - if (!(lflags & LOG_NEWLINE)) { - if (cont_add(caller_id, facility, level, lflags, text, text_len)) - return text_len; - } - - /* Store it in the record log */ - return log_store(caller_id, facility, level, lflags, 0, - dict, dictlen, text, text_len); -} - /* Must be called under logbuf_lock. */ int vprintk_store(int facility, int level, const char *dict, size_t dictlen, @@ -2015,8 +1923,8 @@ int vprintk_store(int facility, int level, if (dict) lflags |= LOG_NEWLINE; - return log_output(facility, level, lflags, - dict, dictlen, text, text_len); + return log_store(facility, level, lflags, dict, dictlen, + text, text_len); } asmlinkage int vprintk_emit(int facility, int level, -- 2.20.1
