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Message-Id: <1406037717-9670-2-git-send-email-elder@linaro.org>
Date: Tue, 22 Jul 2014 09:01:56 -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 v2 1/2] printk: kill LOG_CONT
The LOG_CONT and LOG_NEWLINE flags are mutually exclusive, i.e.,
the presence of LOG_NEWLINE implies the absense of LOG_CONT, and
vice-versa. As a result, wherever LOG_CONT is used, we can
equivalently substitute !LOG_NEWLINE; and we can use LOG_NEWLINE
wherever !LOG_CONT is used.
Switch to using LOG_NEWLINE only, and get rid of LOG_CONT. Make
some refinements on a nearby block of comments.
Signed-off-by: Alex Elder <elder@...aro.org>
---
kernel/printk/printk.c | 42 +++++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 21 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 6848e7d..49c9238 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -211,7 +211,6 @@ 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 */
- LOG_CONT = 8, /* text is a fragment of a continuation line */
};
struct printk_log {
@@ -613,22 +612,25 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
do_div(ts_usec, 1000);
/*
- * If we couldn't merge continuation line fragments during the print,
- * export the stored flags to allow an optional external merge of the
- * records. Merging the records isn't always necessarily correct, like
- * when we hit a race during printing. In most cases though, it produces
- * better readable output. 'c' in the record flags mark the first
- * fragment of a line, '+' the following.
+ * Sometimes it's necessary to flush an incomplete record to the log.
+ * When this happens, consecutive records should be merged to produce
+ * a logically complete message.
+ *
+ * Indicate this to user space with a flag character. A 'c' indicates
+ * the first of a series of incomplete log records. A '+' indicates
+ * a record that should be merged with one or more earlier records.
+ * And a '-' indicates a "normal" self-contained single record.
*/
- if ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))
+ if (!(user->prev & LOG_NEWLINE) && !(msg->flags & LOG_PREFIX))
cont = '+';
- else if (msg->flags & LOG_CONT)
+ else if (!(msg->flags & LOG_NEWLINE))
cont = 'c';
else
cont = '-';
/* Insert a newline if the previous line was not terminated properly */
- insert_newline = (user->prev & LOG_CONT) && (msg->flags & LOG_PREFIX);
+ insert_newline = !(user->prev & LOG_NEWLINE) &&
+ (msg->flags & LOG_PREFIX);
len = sprintf(user->buf, "%s%u,%llu,%llu,%c;",
insert_newline ? "\n" : "",
(msg->facility << 3) | msg->level,
@@ -1007,13 +1009,13 @@ static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev,
bool newline = true;
size_t len = 0;
- if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))
+ if (!(prev & LOG_NEWLINE) && !(msg->flags & LOG_PREFIX))
prefix = false;
- if (msg->flags & LOG_CONT)
+ if (!(msg->flags & LOG_NEWLINE))
newline = false;
- if ((prev & LOG_CONT) && (msg->flags & LOG_PREFIX) && len < size) {
+ if (!(prev & LOG_NEWLINE) && (msg->flags & LOG_PREFIX) && len < size) {
if (buf)
buf[len++] = '\n';
else
@@ -1081,7 +1083,7 @@ static int syslog_print(char __user *buf, int size)
*/
syslog_seq = log_first_seq;
syslog_idx = log_first_idx;
- syslog_prev &= LOG_NEWLINE|LOG_CONT;
+ syslog_prev &= LOG_NEWLINE;
syslog_partial = 0;
}
if (syslog_seq == log_next_seq) {
@@ -1210,7 +1212,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
*/
seq = log_first_seq;
idx = log_first_idx;
- prev &= LOG_NEWLINE|LOG_CONT;
+ prev &= LOG_NEWLINE;
}
}
}
@@ -1319,7 +1321,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
*/
syslog_seq = log_first_seq;
syslog_idx = log_first_idx;
- syslog_prev &= LOG_NEWLINE|LOG_CONT;
+ syslog_prev &= LOG_NEWLINE;
syslog_partial = 0;
}
if (from_file) {
@@ -1534,7 +1536,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len)
if (cont.len + len > sizeof(cont.buf)) {
/* the line gets too long, split it up in separate records */
- cont_flush(LOG_CONT);
+ cont_flush(0);
return false;
}
@@ -1552,7 +1554,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len)
cont.len += len;
if (cont.len > (sizeof(cont.buf) * 80) / 100)
- cont_flush(LOG_CONT);
+ cont_flush(0);
return true;
}
@@ -1665,8 +1667,6 @@ asmlinkage int vprintk_emit(int facility, int level,
if (text_len && text[text_len-1] == '\n') {
text_len--;
lflags = LOG_NEWLINE;
- } else {
- lflags = LOG_CONT;
}
/* strip kernel syslog prefix and extract log level or control flags */
@@ -2167,7 +2167,7 @@ again:
if (console_seq < log_first_seq) {
len = sprintf(text,
"%s** %u printk messages dropped **\n",
- (console_prev & LOG_CONT) ? "\n" : "",
+ (console_prev & LOG_NEWLINE) ? "" : "\n",
(unsigned)(log_first_seq - console_seq));
/* Messages are gone, move to first one. */
console_seq = log_first_seq;
--
1.9.1
--
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