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Message-Id: <1405619953-5475-5-git-send-email-elder@linaro.org>
Date: Thu, 17 Jul 2014 12:59:12 -0500
From: Alex Elder <elder@...aro.org>
To: akpm@...ux-foundation.org
Cc: kay@...y.org, pmladek@...e.cz, bp@...e.de, john.stultz@...aro.org,
jack@...e.cz, linux-kernel@...r.kernel.org
Subject: [PATCH 4/5] printk: kill LOG_PREFIX
The only place that uses LOG_PREFIX is log_store(), and that
now strips it from the flags field before recording it in a log
buffer.
Switch to passing a Boolean flag to log_store() to indicate whether
this record should force a new record--that is, complete the
previous one--and eliminate the LOG_PREFIX flag altogether. Update
a few comments as well.
Signed-off-by: Alex Elder <elder@...aro.org>
---
kernel/printk/printk.c | 60 ++++++++++++++++++++++++++------------------------
1 file changed, 31 insertions(+), 29 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index df38b5e..bfc2581 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -210,7 +210,6 @@ static int console_may_schedule;
enum log_flags {
LOG_NOCONS = 1, /* already flushed, do not print to console */
LOG_NEWLINE = 2, /* text ended with a newline */
- LOG_PREFIX = 4, /* text started with a prefix */
};
struct printk_log {
@@ -397,7 +396,7 @@ static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len,
}
/* insert record into the buffer, discard old ones, update heads */
-static int log_store(int facility, int level,
+static int log_store(int facility, int level, bool force_new,
enum log_flags flags, u64 ts_nsec,
const char *dict, u16 dict_len,
const char *text, u16 text_len)
@@ -432,11 +431,8 @@ static int log_store(int facility, int level,
* If we're forcing a new log record, update the flags for
* the previous one to mark it complete.
*/
- if (flags & LOG_PREFIX) {
- if (log_last_msg)
- log_last_msg->flags |= LOG_NEWLINE;
- flags &= ~LOG_PREFIX;
- }
+ if (force_new && log_last_msg)
+ log_last_msg->flags |= LOG_NEWLINE;
msg = (struct printk_log *)(log_buf + log_next_idx);
memcpy(log_text(msg), text, text_len);
@@ -1493,7 +1489,7 @@ static struct cont {
u64 ts_nsec; /* time of first print */
u8 level; /* log level of first message */
u8 facility; /* log level of first message */
- enum log_flags flags; /* prefix, newline flags */
+ enum log_flags flags; /* nocons, newline flags */
bool flushed:1; /* buffer sealed and committed */
} cont;
@@ -1510,7 +1506,7 @@ static void cont_flush(enum log_flags flags)
* console; wait for the console to pick up the rest of the
* line. LOG_NOCONS suppresses a duplicated output.
*/
- log_store(cont.facility, cont.level, flags | LOG_NOCONS,
+ log_store(cont.facility, cont.level, false, flags | LOG_NOCONS,
cont.ts_nsec, NULL, 0, cont.buf, cont.len);
cont.flags = flags;
cont.flushed = true;
@@ -1519,7 +1515,7 @@ static void cont_flush(enum log_flags flags)
* If no fragment of this line ever reached the console,
* just submit it to the store and free the buffer.
*/
- log_store(cont.facility, cont.level, flags, 0,
+ log_store(cont.facility, cont.level, false, flags, 0,
NULL, 0, cont.buf, cont.len);
cont.len = 0;
}
@@ -1596,6 +1592,7 @@ asmlinkage int vprintk_emit(int facility, int level,
int this_cpu;
int printed_len = 0;
bool in_sched = false;
+ bool force_new = false;
/* cpu currently holding logbuf_lock in this function */
static volatile unsigned int logbuf_cpu = UINT_MAX;
@@ -1640,7 +1637,7 @@ asmlinkage int vprintk_emit(int facility, int level,
recursion_bug = 0;
text_len = strlen(recursion_msg);
/* emit KERN_CRIT message */
- printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
+ printed_len += log_store(0, 2, true, LOG_NEWLINE, 0,
NULL, 0, recursion_msg, text_len);
}
@@ -1676,7 +1673,7 @@ asmlinkage int vprintk_emit(int facility, int level,
if (level == -1)
level = kern_level - '0';
case 'd': /* KERN_DEFAULT */
- lflags |= LOG_PREFIX;
+ force_new = true;
}
/*
* No need to check length here because vscnprintf
@@ -1691,36 +1688,40 @@ asmlinkage int vprintk_emit(int facility, int level,
if (level == -1)
level = default_message_loglevel;
- if (dict)
- lflags = LOG_PREFIX|LOG_NEWLINE;
+ if (dict) {
+ force_new = true;
+ lflags = LOG_NEWLINE;
+ }
if (!(lflags & LOG_NEWLINE)) {
/*
- * Flush the conflicting buffer. An earlier newline was missing,
- * or another task also prints continuation lines.
+ * We're recording an incomplete record. We'll add it to the
+ * "cont" buffer if possible, but if it contains data written
+ * by somebody else we need to flush that to the log first.
*/
- if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
+ if (cont.len && (force_new || cont.owner != current))
cont_flush(LOG_NEWLINE);
- /* buffer line if possible, otherwise store it right away */
+ /* If we're unable to buffer it, store it immediately */
if (cont_add(facility, level, text, text_len))
printed_len += text_len;
else
- printed_len += log_store(facility, level, lflags, 0,
- NULL, 0, text, text_len);
+ printed_len += log_store(facility, level, force_new,
+ lflags, 0, NULL, 0,
+ text, text_len);
} else {
bool stored = false;
/*
- * If an earlier newline was missing and it was the same task,
- * either merge it with the current buffer and flush, or if
- * there was a race with interrupts (prefix == true) then just
- * flush it out and store this line separately.
- * If the preceding printk was from a different task and missed
- * a newline, flush and append the newline.
+ * This record is complete (it should be formatted with a
+ * newline), so we'll be writing it to the log. If there
+ * are any incomplete records buffered we will need to
+ * flush those to the log first. If possible, we'll add
+ * this record to the buffer first. If there's nothing
+ * buffered, just write this record to the log.
*/
if (cont.len) {
- if (cont.owner == current && !(lflags & LOG_PREFIX))
+ if (cont.owner == current && !force_new)
stored = cont_add(facility, level, text,
text_len);
cont_flush(LOG_NEWLINE);
@@ -1729,8 +1730,9 @@ asmlinkage int vprintk_emit(int facility, int level,
if (stored)
printed_len += text_len;
else
- printed_len += log_store(facility, level, lflags, 0,
- dict, dictlen, text, text_len);
+ printed_len += log_store(facility, level, force_new,
+ lflags, 0, dict, dictlen,
+ text, text_len);
}
logbuf_cpu = UINT_MAX;
--
1.9.1
--
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