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-rw-r--r--kernel/printk.c105
1 files changed, 61 insertions, 44 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 915a8be10b5f..32462d2b364a 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1264,13 +1264,13 @@ asmlinkage int vprintk_emit(int facility, int level,
const char *fmt, va_list args)
{
static int recursion_bug;
- static char buf[LOG_LINE_MAX];
- static size_t buflen;
- static int buflevel;
+ static char cont_buf[LOG_LINE_MAX];
+ static size_t cont_len;
+ static int cont_level;
+ static struct task_struct *cont_task;
static char textbuf[LOG_LINE_MAX];
- static struct task_struct *cont;
char *text = textbuf;
- size_t textlen;
+ size_t text_len;
unsigned long flags;
int this_cpu;
bool newline = false;
@@ -1320,15 +1320,15 @@ asmlinkage int vprintk_emit(int facility, int level,
* The printf needs to come first; we need the syslog
* prefix which might be passed-in as a parameter.
*/
- textlen = vscnprintf(text, sizeof(textbuf), fmt, args);
+ text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
/* mark and strip a trailing newline */
- if (textlen && text[textlen-1] == '\n') {
- textlen--;
+ if (text_len && text[text_len-1] == '\n') {
+ text_len--;
newline = true;
}
- /* strip syslog prefix and extract log level or flags */
+ /* strip syslog prefix and extract log level or control flags */
if (text[0] == '<' && text[1] && text[2] == '>') {
switch (text[1]) {
case '0' ... '7':
@@ -1338,49 +1338,67 @@ asmlinkage int vprintk_emit(int facility, int level,
prefix = true;
case 'c': /* KERN_CONT */
text += 3;
- textlen -= 3;
+ text_len -= 3;
}
}
- if (buflen && (prefix || dict || cont != current)) {
- /* flush existing buffer */
- log_store(facility, buflevel, NULL, 0, buf, buflen);
- printed_len += buflen;
- buflen = 0;
- }
+ if (level == -1)
+ level = default_message_loglevel;
- if (buflen == 0) {
- /* remember level for first message in the buffer */
- if (level == -1)
- buflevel = default_message_loglevel;
- else
- buflevel = level;
+ if (dict) {
+ prefix = true;
+ newline = true;
}
- if (buflen || !newline) {
- /* append to existing buffer, or buffer until next message */
- if (buflen + textlen > sizeof(buf))
- textlen = sizeof(buf) - buflen;
- memcpy(buf + buflen, text, textlen);
- buflen += textlen;
- }
+ if (!newline) {
+ if (cont_len && (prefix || cont_task != current)) {
+ /*
+ * Flush earlier buffer, which is either from a
+ * different thread, or when we got a new prefix.
+ */
+ log_store(facility, cont_level, NULL, 0, cont_buf, cont_len);
+ cont_len = 0;
+ }
- if (newline) {
- /* end of line; flush buffer */
- if (buflen) {
- log_store(facility, buflevel,
- dict, dictlen, buf, buflen);
- printed_len += buflen;
- buflen = 0;
- } else {
- log_store(facility, buflevel,
- dict, dictlen, text, textlen);
- printed_len += textlen;
+ if (!cont_len) {
+ cont_level = level;
+ cont_task = current;
}
- cont = NULL;
+
+ /* buffer or append to earlier buffer from the same thread */
+ if (cont_len + text_len > sizeof(cont_buf))
+ text_len = sizeof(cont_buf) - cont_len;
+ memcpy(cont_buf + cont_len, text, text_len);
+ cont_len += text_len;
} else {
- /* remember thread which filled the buffer */
- cont = current;
+ if (cont_len && cont_task == current) {
+ if (prefix) {
+ /*
+ * New prefix from the same thread; flush. We
+ * either got no earlier newline, or we race
+ * with an interrupt.
+ */
+ log_store(facility, cont_level,
+ NULL, 0, cont_buf, cont_len);
+ cont_len = 0;
+ }
+
+ /* append to the earlier buffer and flush */
+ if (cont_len + text_len > sizeof(cont_buf))
+ text_len = sizeof(cont_buf) - cont_len;
+ memcpy(cont_buf + cont_len, text, text_len);
+ cont_len += text_len;
+ log_store(facility, cont_level,
+ NULL, 0, cont_buf, cont_len);
+ cont_len = 0;
+ cont_task = NULL;
+ printed_len = cont_len;
+ } else {
+ /* ordinary single and terminated line */
+ log_store(facility, level,
+ dict, dictlen, text, text_len);
+ printed_len = text_len;
+ }
}
/*
@@ -1470,7 +1488,6 @@ EXPORT_SYMBOL(printk);
#define LOG_LINE_MAX 0
static struct log *log_from_idx(u32 idx) { return NULL; }
static u32 log_next(u32 idx) { return 0; }
-static char *log_text(const struct log *msg) { return NULL; }
static void call_console_drivers(int level, const char *text, size_t len) {}
static size_t msg_print_text(const struct log *msg, bool syslog,
char *buf, size_t size) { return 0; }